Saturday, February 2, 2008

Oil Service and Inspection

The car has been running beautifully the last couple of months so I haven't needed to do much to it, but this weekend I realized I was within a hundred miles of a scheduled oil service. I decided to do it early simply because I was presented with a sunny day and temperatures in the 40's. Well...that and the realization that we could be knee deep in snow by next weekend in spite of the fact I hedged against that possibility with the installation of snow tires this season.

This time around the INSPECTION indicator illuminated so since I've assumed responsibility for the inspection process and progressive maintenance schedule I felt the vehicle deserved some additional attention. I normally conduct a weekly inspection of the engine bay just to check for obvious problems (leaks, belt tension, fluids, etc.) but it's not every day I am able to get under the car and look around. These days I'm most concerned about the front end since all the parts have 100K or more on them, but amazingly the car doesn't seem to want anything. It drives almost perfectly and I'm hesitant to just throw money at the car for no good reason, particularly because I'm in no short supply of things that demand the attention of my wallet these days.

On the other hand, suspension parts are kind of tricky as they tend to wear so slowly that it's difficult to recognize how much ride quality has deteriorated unless new parts are installed. Given this and the fact that BMW puts a 100K life limit on the struts I have plans to do some suspension rework this year, but as a result of this inspection I don't think I'm under any time pressure to do it. All other things being equal, I suppose I'll wait until I can do the work in short sleeves.

The oil service went as expected and I took another sample that came back clean (ignore the comment about the engine being 2.5L...it is, in fact, a 2.8L M52). Blackstone doesn't apparently read the data I send in). Although I expect the engine will continue to run smoothly with no major work until at least 200K, at 155K miles I believe I have finally entered the "region of reversed command" as we pilots say. No matter how well I treat the thing, metals wear, seals dry out, and gaskets blow out. Anything is possible at this point. In my opinion 150K is a lot to expect of any engine, BMW or not. This M52 owes me nothing.

Dunlop Winter Sport M3 Review

After 2000 miles and a minor bout with the white stuff recently I figured I'd provide a review of the Winter Sport M3.

• Snow / Sleet: The deepest snow I've hit so far is about 2" with a lot of sleet and freezing rain mixed in. In those conditions the tires won't let you violate the laws of physics more than any other tire, but I can honestly say that the car is more sure-footed clad with the Winter Sport M3. Steering is very "quiet" and doesn't yank the wheel around when changing lanes in snowy conditions, while the rear also feels "planted" or far more predictable -- even when I turn ASC off, give it a bit of throttle and drift around the corners.
• Normal Grip: During normal cold weather, both dry and wet conditions, the tire inspires more than the Pilot Sport A/S. No surprise, really. The benefits of a snow tire are not limited to the deep tread pattern. The rubber is specially designed to remain soft and grippy when it's cold, and the result is a tire that feels almost like a pencil eraser...even when it's below freezing.
• Wet: The deep grooves in the Dunlop's tread no doubt contribute to the tire's hydroplaning resistance. I drove home in a cold, torrential rain the other night with deep puddles everywhere and the tires just went right through them without yanking the wheel out of my hands. This is probably the best rain tire I've found.
• Dry: Dry performance is quite predictable, though precision is somewhat lacking. I can't say whether this lack of precision is due to the tire or the simple fact that I've been spoiled by running 18" high performance low profile tires, but I am amazed that I haven't lost more by going back to the small tire, wheel, and a winter tire to boot. That's a win in my book.
• Noise: As far as noise is concerned, they are very quiet in dry conditions. They are a bit noisier in wet conditions but their superior grip and hydroplaning resistance more than make up for that.
• Quality: While cleaning the wheels this weekend I noticed that the tires were made in Germany. Perhaps that explains why they balanced with such low road force numbers. This may also explain why BMW actually certified the Winter Sport M2 (the M3's predecessor) for use on their cars. In short, the Winter Sport tires seem to do well on BMWs.
• Treadwear: It's too early to tell how good the treadwear is, but the tires still look brand new. I imagine I'll get at least two seasons (about 5 months each) out of them before reaching the first tread wear indicator which indicates "less than optimal snow performance".

Overall rating: 9 out of 10. Definitely recommended.

Ten Years

This month the E36 is ten years old and I must admit that in what little idle time I've had lately I've been playing out "what if" scenarios.

What if the car got blasted in an accident? What if another deer attempted to mate with the car in a hormonally charged stupor of rutting season? Would I repair it? Answer: Probably not given that BMW will bring the 1 series to our shores in a few short months. There is just too much potential in the 135i to ignore it and there is a definite point at which putting money into an old car makes absolutely no sense for a daily driver because it's like driving without insurance. No insurance company will give me 15K of collision coverage on a car worth 5K...even if it takes a "mere" 10K to repair it. That's why they'll total an old car as easily as look at it with even the smallest of damage estimates.

What would I do if the engine blew up or I was forced to do some other major engine work? There is a new kit on the market that makes it almost a no-brainer to drop a LSx V8 crate engine in the car. Sounds like a crazy idea, I know, but the videos of this car are enough to make me giddy. On the other hand, it would be a lot easier (as well as more respectful to the BMW marque) to simply rebuild the M52 with forged internals and slap a twin screw supercharger on it. I guess it would all depend on how adventurous I felt at the time. I don't think I could go for any solution that would take the car off the road permanently courtesy of the frickin' smog nazis, but both options are doable as far as emissions are concerned if one lives anywhere but the Republik of Kalifornia.

A third and far more likely scenario begs to ask "What if I simply could no longer ignore the lure of the little 135i hotrod"? I refuse to own more than two "daily drivers", so in this case I would have to relegate the E36 to track duty or sell it. The problem, of course, with turning it into a track car is that it would at the very least involve swapping out most of the suspension for M3 parts and swapping the auto for a 6 speed. That's 10K easy, and assumes that I'd want to destroy the value inherent in an all-original BMW like this one. The problem with simply trading it for something new is that it would rob me of the fun I have and the knowledge I gain by fixing stuff that breaks on an old car. I mean, anybody can write a check for a car every month. Where the hell is the fun in that?

The day may come sooner than I'd like that I'll have to make a hard decision about my baby. For now, though, I'll celebrate the fact that the car I took a huge chance on ten years ago is still with me, eager to take me anywhere I want to go in style and performance that rivals many of its far younger brethren.

Mileage: 155471, Parts: $64, Parts Saved: $10, Labor Saved: $85

Saturday, April 5, 2008

Summer Rubber

As the calendar turned to April and the threat of winter weather here in New Jersey diminished I felt it was time to return to summer rubber. This would have been a simple 15 minute tire swap but I had some other plans (see below).

The one thing I noticed in doing the tire swap is that the winter wheels came off the hubs very easily thanks to the anti-seize compound I put on the hub last time. Since the 18" CSL reps are machined to fit a bit tighter to the hub I made it a point to clean off the old compound before I applied a new coat. Guess I'll wait and see next fall if this will make my life easier. I expect it to.

Naturally, I used my air impact wrench to remove the lug bolts and that made very quick work of that task. When it came time to reinstall the bolts I started all five by hand and then used my air ratchet with a 3/8" to 1/2" adapter and the same 17 mm socket to get all the bolts within a few turns of final torque. Worked like a charm and saved me a couple minutes each wheel. I recommend this technique if you have the tools.

But whatever you do, don't use an impact wrench to tighten the lug bolts. That seems like a good idea and a real time saver...right up to the point that you bust a knuckle or two trying to use the OE tire iron to break the bolts free to swap on a spare out in the middle of nowhere. Always torque your lug bolts using a torque wrench.

Brake Fluid Flush

Although the brake fluid flush wasn't technically due until June I figured I'd take care of it myself while the wheels were off. This was my first time working with the critical brake hydraulics so long before I opened a single bleeder screw I did a ton of research on the usual BMW forums, bought the right tools, and confirmed the best practices with my technician. As a result, the flush went exactly as expected and only took me about 45 minutes.

Modern BMWs require DOT 4 brake fluid. Although any DOT 4 fluid will work for a street car, I picked up some good quality ATE TYP200 gold fluid from Steve at Ultimate Garage for the simple reason that his facilities are here in New Jersey and knew I could ship via ground to keep the cost down and yet get it delivered next day -- and that's exactly what happened.

This was also the first time I used all four jack stands to keep the car level during the flushing process. I jacked the front first with the rear wheels chocked and the parking brake applied, got the stands under the front stable, and then carefully jacked the rear before throwing the second set of stands under the rear jack points. This gave me the confidence I'll need to do transmission fluid flushes, among other work that necessitates all four corners up in the air.

Cost Analysis

The typical cost for this service at a BMW dealer is almost $200, so I saved about $170 in labor doing the job myself.

As far as tools and equipment are concerned, I bought the "Black Label" Motive Pressure Bleeder for about $60. I already had the 7mm and 9mm box end wrenches required to open the front and rear bleeder screws, respectively, so no direct costs there. The collection bottle was made from a spare water bottle and copper wire (no shortage around here since I'm an electrician), and some 1/4" I.D hose from Home Depot that cost less than $5. So the "real" savings is only about $90 this time around, but the effective savings will ultimately improve in future years as I take over yet another job I previously left to the dealer techs.

Mileage: 158457, Tools: $60, Parts: $20, Labor Saved: $170

Sunday, April 20, 2008

Valve Train Noise

As the odometer has crept over 159000 miles I've noticed slightly more valve train noise in the morning after start. It sounds like classic tappet noise and only a couple tappets appear to be making noise. It is nothing obvious or distracting -- just more noticeable until the car warms up...then it purrs like a kitten. Nothing I can really do about this as I understand it is normal for an engine of this age.

OBC Lamp Replacement

This week the bulb that backlights the clock LCD in the OBC failed. Rather than bug my technician for something so trivial I decided to pull out the OBC and fix it myself. In fact, it took me more time to adjust the camera to take the pictures for this log than it did to actually replace the bulb.

Last time I had a bulb failure in the OBC my technician took care of it while I was in the shop getting some other work done. Normally, technicians just replace all the bulbs because their labor is expensive relative to the parts and it's better from a customer relations perspective to replace all the bulbs rather than fix one bulb and force the customer return several times to replace the other bulbs as they fail, but since my labor is "free" and the bulbs cost almost $3 a piece, I felt there was no point in throwing $12 at a $3 problem.

Access to the latching mechanism is provided by a hole in the top of the tray beneath the OBC. To release the OBC I stuck my index finger in the hole and then pushed directly upward. At the same time, I managed to get my middle finger slightly behind the OBC while I used a screwdriver to carefully pull the top of the glasses tray down an 1/8" or so to help unlock the unit. With about 10 seconds of fiddling the OBC popped loose.

The bulbs are the same 1/4 turn type used on the back of the speedo / tach gauge cluster and required only a small screwdriver to remove and reinstall. The four OBC bulb sockets are highlighted in the photo with arrows. Mission accomplished.

Exterior Trim Restoration Experiment

Although I've been forced to replace the exterior side mouldings on this car more than once, the trim on the front and rear bumpers is original...and it shows. The plastic is faded and generally looks like crap even if I hit it with some 303 Aerospace Protectant. Replacement mouldings for the front and rear bumpers aren't terribly expensive, but I have other things on which to spend $200, so I decided to try an experiment before I ordered new trim.

I read about various black trim restoration kits and settled on the Leatherique Rubber Black restorer ($25). Rather than sacrifice a piece of trim currently installed on the car and commit myself to a long job I decided to use some of the old rubber side mouldings I'd saved. The directions on the bottle indicated that I should use a poly brush to avoid brush marks. That struck me as odd because most dyes would not be affected by this, but as I opened the bottle it became clear that this is more of a paint than a dye. Don't get me wrong...it may have dye in it, and as as far as paints go it's fairly thin, but it's not the watery consistency of Rit or similar dyes. Since I did not have a poly brush handy and really didn't want to make a special trip to the home center to get one just to sacrifice for this experiment I used the only thing I had -- a spare paint roller with a 1/4" nap.

I shook the product for 10-15 seconds before I opened the container and poured a bit of it on the end of the roller. I then smoothly and carefully applied the product over the length of the trim, and let it dry about 30 seconds before wiping off the excess and taking care to avoid the combination of pressure and direction of travel that would tend to produce any "brush marks". The result is shown in the picture. If it's not obvious, the old, faded trim is on the left and the newly "restored" trim is on the right. Judge for yourself.

I'm not convinced this trim restorer product is the best solution available, but the improvement is notable in spite of the fact that some brush marks are visible in the finish. The overall tonal quality of the trim is more uniform and given a shot of Aerospace Protectant I'm sure it would look like new. Of course, the trim on which I experimented has a smooth finish while the front and rear trim I endeavor to restore has a grainy texture that may not take to this process as well...that is unless I were to apply it with an airbrush or similar. The product directions (such as they are) do suggest spraying it to avoid brush marks. Fortunately, I have a need for an airbrush to touch up some rivets on the airplane following some airframe repair work so I may buy one and use it for a second experiment on the remaining trim piece. Something tells me I'll wind up ordering new trim in any case, but at least I can order it with a clear conscience knowing that I made a best effort to repair it.

Mileage: 159000, Parts: $30

Sunday, April 26, 2008

Rear Trim Restoration

Following last weekend's experiment I decided to apply the Leatherique Rubber Black trim restorer to the rear bumper trim. I started the process yesterday and did everything necessary to clean and prep the trim to remove any wax or protectant left over from last year's detailing sessions. I applied the product and feathered it out for a uniform appearance as I did last weekend. The textured trim actually took the product better than the side mouldings. I let it dry overnight and was completely satisfied with the results, right up to the point that the product started to come off on my hands while reinstalling the parts this morning.

This confirmed my suspicion that Rubber Black is, in fact, a paint and not a dye. That's not to say that there is no dye whatsoever in the product and that the trim isn't permanently darker at this point, but seriously -- if I wanted a surface covering to mask the problem rather than a dye to penetrate the trim material I would have bought a can of Krylon.

I managed to cover the blotchiness now apparent in the trim with some 303 Aerospace Protectant, and expect to purchase new trim parts eventually. I already had plans to do this so as long as I can get the vendor to give me a credit for the Rubber Black product I'll just chalk it up to experience and remind myself once again that there is no free lunch in this world. You want to repair faded trim? Buy new trim. You want to keep the trim looking new from that point on? Regularly apply a protectant with UV protection like 303 Aerospace Protectant. Simple as that.

Aux Cooling Fan Bearing Failure

Some time ago I realized that one of the reasons my A/C compressor was making a lot of noise was because the aux fan wasn't running. That turned out to be caused by the failure of the low-speed fan relay. I commented at the time that I was happy to save the cost of a new aux fan because the OE part is surprisingly expensive, even by BMW standards. Even with the aux fan repaired at the time I still noticed a bit of noise coming from the compressor but it was far less noticeable than before.

Today while doing my weekly under-the-hood inspection I decided to run the A/C for the first time this season. The compressor exhibited the typical low-level rumbling (marbles in a foam lined can) sound I have come to accept from this 10 year old unit, but what I did not expect to hear was a short scraping / grinding noise that seemed to reoccur every 30 seconds or so. I kneeled in front of the car, peered through the grill and watched the aux fan start up normally and then generate the noise as it shut down abruptly. I know that the fan is supposed to cycle as needed, but it's supposed to coast to a stop -- not grind to a halt in little more than one second. I removed the cover on the top of the radiator to gain access to the fan, grabbed one of the blades and gave it a tug. That clearly demonstrated the source of the noise -- bad bearings. The motor is shot and needs to be replaced before it gets too hot or before I use the A/C.

I spent a good half hour searching various BMW parts houses online to find the best price. The OE part from Tischer is $515 with their usual awesome discount -- a good price for the OE part but still excessive for what is basically a two speed fan. Bavarian Auto advertised an aftermarket equivalent (possibly OEM but I'm not sure) for $320. I decided that it was worth going with an aftermarket part to save $200 but I nevertheless continued searching for other prices.

That's when Google stumbled on well-known BMW specialty house Koala Motorsport. I didn't even know they sold individual BMW parts (Brett, owner of Koala, is more known in the industry for his differentials) but was pleasantly surprised to find greater savings there. Brett's price? $250 including shipping, or about half the price of the OE part. The thing that convinced me to buy from Brett? Unlike most BMW parts houses that just say something stupid like "BMW fan assembly" in the part description field, Koala's product description included a reasonably sized picture so I could compare my part to theirs and a comment that could only come from an experienced BMW technician like Brett: "This assembly includes the main mounting shroud, which becomes brittle with age and may not survive the fan replacement process". That simple statement (plus another that confirmed what the specific part number included) made the sale.

I should have the fan assembly later this week and expect to do the installation next weekend. I pulled the TIS description for this work and it appears that I'll need to remove the bumper cover to get at it. Should be an interesting project.

Mileage: 159260

Sunday, May 4, 2008

Aux Cooling Fan Replacement

As expected the aux fan arrived from Koala Motorsport this week. I was so busy this weekend with more pressing regular life matters I almost didn't get the time to install the part, but I managed to get the other work done ahead of time and install the new fan.

While the BMW TIS suggests you need to remove the bumper cover to remove the fan and frame assembly, that is incorrect. I just removed a few protective panels attached to the bottom of the bumper cover and six screws on the fan assembly itself and the fan assembly slid right out the bottom of the car.

I stopped by the dealer earlier this week to get a quote on the work. It turned out that if I knew nothing about my car and just walked into the dealer to get this done my wallet would be lighter by a whopping $805 rather than the $250 it cost me to buy an aftermarket part and do the job myself. Unlike most jobs where labor dominates the cost the vast majority of this repair is sunk in the cost of the part, which is a staggering $642. That's just crazy. I see no reason to buy the OE part when the aftermarket part looks and appears to function identically to it.

I took apart the old fan to figure out what failed. The rotor (rotating assembly) of the electric motor was in good shape, but the permanent magnets that surrounded the rotor were broken in several places. Moving the rotor back and forth caused the magnet fragments to move around and bunch up with each other. This caused a lot of friction in the rotating assembly and frankly I'm surprised the motor actually worked in this condition. Hello, garbage man? I have a ten year old aux fan for ya...

Now for the fun part - cost analysis. Retail price for the OE fan is $642. I paid $240 and change + shipping, or $252 total. This is a savings of almost $400. The quote at the dealer for this job was $805. $805 - $642 = $163 in labor I saved by doing this job myself. The total savings is obviously $805 - $252 or $553. Not a bad payday for a few hours of research and wrenching, don't you think? DIY. It's the thing to do. Seriously.

Mileage: 159633, Parts: $252, Parts Saved: $390, Labor Saved: $163

Saturday, May 17, 2008

Oil Service, Fuel Filter

This week the car passed 160K miles and that prompted a check of my maintenance schedule. That revealed the need for an oil service, a fuel filter change, and a coolant flush. I knew the oil service would be easy enough, but the fuel filter and coolant flush would be firsts for me as DIY procedures.

After doing some research on the usual forums I realized that replacing the fuel filter would be a relatively simple process but I decided to wait on the coolant flush until I had received a clarification of one aspect of the procedure from a few other sources before tackling it. Better safe than sorry, especially when a $150 oxygen sensor is involved. Long story. I'll explain it when the time comes.

I expect to detail the fuel filter process in a DIY soon so I won't go into detail here but I will tell you that the way gasoline eats through polyisocyanurate insulation panels (you know, the stuff they put under residential siding and the very same panels I use to line the gravel driveway when I work outside under my car) is kind of cool. What's not cool is how the chemical reaction creates an evil goo that remains in molten form just long enough to find it's way into an unsuspecting DIY technician's hair.

Further, I learned that it is really hard to get the goo out of said technician's hair after the gasoline evaporates and the foam resolidifies unless one uses a solvent like, oh, say, gasoline applied to a blue shop towel to remove it. To borrow an old shampoo marketing slogan, "Gee, your hair smells like gasoline and polyisocyanurate foam". Oh well. If I get cancer, at least I'll know why. :-|

The labor rate at my dealer is now $110/hour so the labor savings from DIY oil services has risen as well. I now save about $90 in labor and $10 in parts doing this myself. The oil ran about $50 and the oil analysis remains about $20, so the basic cost for a DIY oil service and analysis at this point is $70 in parts.

The fuel filter was $30 and the labor to replace it at the dealer is $70. As usual the 7% sales tax largely offset the 10% CCA discount on the parts, so I saved $70 doing this myself.

Mileage: 160180, Parts: $100, Parts Saved: $10, Labor Saved: $160

Saturday, May 24, 2008

Fuel System Cleaner

As I mentioned in a prior blog entry BMW recently switched its recommended fuel system cleaner. I was told it had something to do with the change to ethanol based fuels but I don't know if that's true. What I do know is that the old stuff used to come in a small white translucent bottle like that depicted in my Fuel Pump DIY article and cost about $4. The new stuff comes in an opaque black bottle that looks suspiciously (read: exactly) like the one used for Techron sold in the aftermarket and costs $12.

I have long known that Techron sells for about $8 a bottle in the aftermarket so I felt I was getting a good deal buying BMW's fuel system cleaner for $4. Since that product is no longer available and I really didn't want to pay 50% more for what is very likely Techron relabled for BMW I decided to buy a bottle of Techron while at my local auto supply and drop it in the tank this week.

I still haven't figured out whether it makes sense to pay even $8 for what is largely Stoddard Solvent (a.k.a. mineral spirits, paint thinner, etc.), naphtha, and some xylene and benzene mixed in along with an almost insignificant amount of the proprietary detergent called Techron, but I suppose I'll figure it out when I have my fuel injectors flow balanced or pull the head off the engine.

This rebranding thing isn't new, incidentally. Auto manufacturers are in the business of building cars...not chemical engineering. What's new is that manufacturers aren't even bothering to rebrand certain parts. Case in point: while I was at the parts window I saw one of the techs fulfilling an order for the special 10W-60 oil required by the S54-equipped M3 and the only reference to BMW on the bottle was the part number in small letters on the back. The label looked like any other label you'd find on a bottle of Castrol sold in the aftermarket. The difference here being, of course, that you can't get this specific oil anywhere but a BMW dealer due to exclusivity agreements between Castrol and BMW.

Fuel Filter Inspection

Last week I set the fuel filter aside to drain and dry out because I knew I wanted to eventually cut it open to inspect the element. Today I used a metal bandsaw to cut off the ends of the filter and was pleasantly surprised to find the paper element completely clean and in one piece.

In fact it was so clean that if I knew for sure that the recommended replacement interval of 36K miles as specified in the TIS was based strictly on some statistical estimate of expected contamination I would gladly extend the interval to something more reasonable like 54K or 72K miles. However, since BMW tends to advocate less than proper maintenance these days I have to believe that the interval is based more on the integrity of the filter medium. For this reason and because the filters are relatively inexpensive and easy to replace I'll likely continue to use the 36K interval.

Oil Analysis

My last oil analysis showed up this week as well and fortunately there's nothing to report. Aside from the tester's comments it looked like a copy of the last analysis...which is exactly what I want to see. All of the wear metals are significantly below the statistical averages and no coolant or other contaminants were found. So the M52 appears to be holding up well passing 160K.

Coolant Flush Research

I've been trying to figure out how to (easily) do a coolant flush involving the block drain without removing the pre-cat O2 sensor that gets in the way of using a box wrench, so today I jacked up the front end to do some experimentation and figured out a few things:

• The coolant drain bolt size is 19mm, and the BMW TIS says the torque is 25 NM (18 ft-lbs)...or the same light torque as the oil drain bolt.
• A box end wrench (SK in this case) will not fit between the tip of the O2 sensor and the face of the bolt because there is only about 3-4 mm of clearance between the two components.
• A straight / standard open-end wrench is a bit unweildy for the work area. I asked Mike Miller of the BMWCCA's "Tech Talk" feature about this process and he suggested I use a stubby wrench. Today I confirmed that while a stubby wrench is not mandatory, it would certainly help.
• I managed to get a standard 19 mm open end wrench on the bolt, but at an uncomfortable angle that might trash the bolt if it doesn't want to come out easily. I may have to buy a crummy 19 mm open end wrench and sacrifice it with my vice to get the exact angle I need. Even then, it will be slow going since there isn't much room to swing a wrench of any kind (stubby or otherwise).
• I don't think the BMW dealer techs (yes, including mine) ever bothered to pull this bolt for a "coolant flush". Frankly, I think they all just drain the radiator, refill with the 50/50 mix and call it a day. At this point I can't say that I blame them, and I may wind up doing it the very same way. Only, if I do, I'll likely switch to an annual coolant flush interval to compensate for leaving a bulk of the old coolant in the block.
• As I took a moment to think while under the car staring at the coolant drain bolt and its juxtaposition to the O2 sensor I think I heard a German engineer laughing manically, but I could be wrong since it occurred at the end of a long day.

More to follow on this procedure when I get around to doing it.

Mileage: 160250, Parts: $8, Parts Saved: $4

Saturday, May 31, 2008

Aux Fan Revisited

Yesterday while running a few errands during lunch I decided to use the air conditioning for the first time this season. Since I knew I had just repaired the aux fan I decided to flick the snowflake button on and walk out in front of the car to make sure the fan was working. To my surprise I found it at a dead stop. Since turning on the air conditioning turns on the aux fan I knew this was a problem, and sure enough I also found the compressor making noise indicative of higher than normal pressure in the system. I turned off the air conditioning to reduce stress on the compressor and pondered the cause while I went about my business and carefully watched the temperature gauge.

While doing the aux fan replacement I noticed the electrical plug fit tightly into the receptacle and required a lot of force to press together. In fact, I had to use a channel-lox pliers to press them together sufficiently for the plastic spring clips to grab properly. I was acutely aware at the time that the connectors might separate so I put a ty-wrap around the spring clips to lock the assembly in place. My first instinct in the troubleshooting process was that this connection had come apart.

Unfortunately, once I got home, put the car up ramps and managed to remove the panels I found the electrical plug in exactly the same condition I'd left it. The first troubleshooting step was to pull the plug to test for power with the engine running and the air conditioning turned on. Under these conditions I found 14 volts DC on one of the terminals (the low-speed side). This meant that the low speed fan relay and the associated fuse were in good shape, so the problem lay with either the fan motor or the electrical plug / receptacle assembly. I turned off the engine to reconnect the plug and then started the engine again to retest it. Thankfully, the fan turned on as expected, which eliminated the fan as the culprit. This little revelation caused me to breathe a sigh of relief because I'd just saved myself from the hassle of cross shipping the fan with a new unit.

Concerned that the poor connection might be due to oxidation on the older contacts of the plug I went over to my brother's electrical van to pull out out a tube of anti-oxidation paste (a conductive dark gray goo that we use whenever mating dissimilar metals like copper and aluminum to prevent corrosion). I used one of my picks (the same ones I use to remove snap rings or the o-ring on the oil filter cannister) to put a very small amount into each female conductor terminal located in the electrical plug. I inserted the connector into the receptacle several times before seating it for good and put a ty-wrap around the spring clips to lock it in place. I tested the fan one last time before I reinstalled the protective panels and called it a day.

I expect to replace this connector assembly with a new waterproof unit but that will have to wait until my schedule permits finding an appropriate part. The only thing that may make it difficult to find is the fact that it must support a minimum of 20 Amps DC continuous running load.

If I had brought this to the dealer they would have charged me a diagnostic charge of around $100 plus the labor to actually fix it, which could have been another hour, or $110. The total process, including searching for the anti-oxidation paste took me about 45 minutes, so I'll just conservatively call it $100 labor saved.

Mileage: 160680; Labor Saved: $100

Saturday, June 07, 2008

Aux Fan Connectors Replaced

A couple days after I "repaired" the aux fan's electrical connection I noticed, once again, that the aux fan would not run with the air conditioning turned on. Knowing full well that much warmer weather was forecast for later in the week and the aux fan would be called provide airflow through the coolant radiator as well as the condenser I decided to fix the problem by replacing the faulty connectors. The problem was identifying the type of replacement connector assembly appropriate for the application.

The primary criteria was current capacity. The aux fan is connected via 14 gauge stranded wire. In 110V AC circuits that's good for about 15 amps, but in 12V DC circuits the same wire size is rated for anywhere from 30-40 amps depending on the length of the wire. This is consistent with the 30 amp fuse used in the aux fan circuit. Further complicating the solution was the need for a sealed connector. The front of the car is regularly battered with water with the addition of salt spray in the winter. Salt and water are enemies of any good electrical connection so I considered a sealed connector essential to the solution.

In my search I stumbled on several connector types including Weatherpak (commonly used on GM products and good for 20 amps), Metri-Pak 280 (good for 30 amps) and Deutsche DTP connectors (25 amp). I gravitated toward the Deutsche connectors primarily because I found they were optionally available with solid contacts rather than the cheaper die stamped equivalents.

The problem? Not only are the Deutche connectors about twice the price of the Weatherpak units (sold as kits including the connector shells and contacts, the plug and receptacle are each about $14), the crimping tools for the solid terminals are ridiculously priced at $300 or more. I managed to find one for $150, but that was still out of the question because I would likely never use it more than once. I asked one supplier advertisting custom fabrication if they would build a connector assembly for me with pigtails so I could splice the assembly into the wiring and avoid the tool purchase. The quote for the completed assembly came in at $72. Expensive for a single connector, but far more reasonable than the nearly $200 I'd pay for the tool and the necessary components.

Unfortunately, by the time I'd gathered this information it was late in the week and I had to use the car in 95+ degree heat today so I managed to splice in some simple crimp-on male/female terminals I had in my spare parts bin. I took a few pictures of the wiring before I cut off the connectors and then reassembled the connectors and checked continuity to make sure the connector was wired as I expected. The resulting fix isn't particularly pretty looking, and even with some electrical tape tightly wrapped around the terminals I would hardly consider the connections sealed, but it should be satisfactory for now.

Later that evening I went to my brother's engagement party at a winery in town. After I pulled into the parking lot I opened the door and walked around to the front of the car to find the fan running as expected. I then reached back into the car and turned off the air conditioning. This time the fan continued to run, no doubt due to the fact that the coolant temperature had exceeded the low-speed theshold as I drove around slowly with little air flowing over the radiator looking for the place. I shut the engine down at that point confident that I'd fixed the problem, but I resolved to replace the terminals with a proper sealed connector as soon as my schedule permits.

Mileage: 161150