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Friday, April 25, 2014

Doug's Domain

Doug Vetter, ATP/CFI

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August 4, 2004

Oil Service, discussions about tranny / diff fluid flushes, possible catalytic converter problem, and Big Brother at BMW

Just another oil service this month. What can I say...I drive the hell out of this thing. The machine also rolled over 100000 miles a week or so ago. All things considered, the car is performing well (and no surprise...it seems at times like I've replaced everything that can be replaced...knock on wood).

I've noticed a slight rubbing / pulsing vibration when turning to the right occasionally, particularly in the morning. I watched my mechanic give the front end a good inspection while the car was up on the lift for the oil service and he said everything is in good shape. I asked whether it could be bearings, and his general thought was "no" simply because these cars don't have problems with bearings as long as the dust seals don't fail. That leaves the most likely case of tires, but they looked good to both of us. They're wearing evenly.

We spoke briefly about flushing the tranny and differential fluid. Turns out the tranny uses common ATF fluid, which is pretty cheap, while the diff uses a more costly synthetic fluid. He said that when he drains tranny fluid it's usually dirty, while the diff fluid looks clear, so my general take on this is unless you're towing something (with a BMW? Yea, I know), you probably should replace the ATF fluid at every other inspection II (every 60K miles) or just do it at 120K miles as BMW recommends on some of their tranny's, and do the diff fluid every 120K miles, if that.

The tranny has a filter, but it's never changed. Automatic transmissions also have a lot of critical seals and valves that can go bad. Unfortunately, when that happens, you're looking at a new tranny. They used to quote labor to repair transmissions in the field but they simply don't do that anymore. And, with the cost of labor and related warranty support issues, who can blame them. It's very likely cheaper and easier just to replace it. Note that I didn't say cheap...I said cheapER. I was late to the appointment and in a rush that day, so I didn't want to wait for the fluids. I told him that we'd do that and a quick test drive of that front end vibration (if it persisted) at the next appointment.

Being the cool guy he is, my mechanic offered to pull the codes from the OBD (no charge) just to make sure everything was running okay, and I watched him as he did it. Turns out that the emissions control subsystem reported two occurrences (the most recent occurring roughly 15 hours ago) of "low catalytic converter efficiency" on cylinders 1-3. I'm not sure exactly how the computer determines this, but I imagine it compares the output of the oxygen sensors on either side of the cats and flags an error if they disagree. This means either one of the cats is on its way out, or maybe one of the oxygen sensors is going bad -- I don't know which.

This should only be of concern before I go for inspection in September of 2005, so I figure I'll burn that bridge when I come to it. I don't know whether I'll even have the car by then (hey, anything can happen), and if it continues to be a rare, intermittent issue that doesn't detrimentally affect performance, I can always make a quick stop by the shop to clear the codes before I go to the DMV. After all, I don't know whether the DMV's computer will flag a single occurrence of this condition as a "major fault". The car's own computer doesn't seem to think it's that big a deal, because it didn't flag the check engine light (and it will only do this if the number of faults exceeds a given threshold). And I'll be damned if I'm going to drop probably almost 2G's with labor just to appease this EcoNazi state.

I also mentioned that I once noticed when in manual mode (A/M switch in "M" position), the shift from 1st to 2nd took a bit longer than I remember. My mechanic and I then discussed the shift adaptation program -- the tranny learns how you drive and adapts the length of the shift to suit that driving style. This means if you drive casually, it will shift smoothly (i.e. take longer to shift), while if you punch it all the time and depress the downshift trigger frequently, it will tend to shift more quickly, and thus more abruptly. He offered to clear the adaptation memory so the tranny would start learning from that point on. I tried to duplicate the condition again after I left the shop, but was unable to do so. I don't know if clearing the memory had any effect, but it was kinda cool to see him use the diagnostic computer to do that.

One interesting thing I learned about the diagnostic computers that BMW dealers use to analyze faults is that they're linked to BMW headquarters. When your car goes in for service the computer dumps the entire memory (not just the parameters the dealer can see or change) and sends it to BMW for analysis. This allows them to track faults and issue service bulletins for "hot" items. Yea, it's a bit "big brother", but that's technology for ya.

Parts $37, Labor, $38, Total $88. Mileage: 100984.

August 26, 2004

New Steering Rack Required

I realize this year the car has been treating me pretty well and I've gotten away with minimal maintenance, so it didn't really surprise me when those strange front-end noises I mentioned in the August 4th update started to get worse. This morning it was particularly obvious, and so I made the decision to drop by the dealer to see if my mechanic could enlighten me about it.

Now I had additional data to give him -- specifically that it did it only when the car was cold, in more locations than one (so it wasn't a characteristic of the road surface), and most recently, with the windows down, I had started to hear a bit of the classic power steering pump "growl" that occurs when fluid is low or the pump is on the way out.

The first thing he asked me is "did you check the fluid level?". Ah, no. I assumed that because power steering fluid (ATF, actually) isn't consumed, and we didn't find any leaks while the car was on the lift, the level was fine. Bad assumption. He unscrewed the cap of the reservoir, (which is below and to the right of the oil filter canister near the front of the engine) and said "well, that's part of the problem". I looked in and saw a white ring partially submerged in oil. "You're not supposed to see that when the fluid is filled to the proper level".

Of course, now I knew why I was hearing the pump growl -- the fluid was too low, but the question now was why? It had to be leaking somewhere. My mechanic instinctively bent down in front of the car, reached under the front end and began to "sssssh" me. I thought for a second he was doing his impression of Dr. Evil (let me tell you a little story about a man named SSSH!) but he asked me to be quiet so he could push on the steering rack tierod end boots. They made a strange mechanical gurgling sound, to which my mechanic proclaimed "bad rack".

"The seals have gone bad and fluid is collecting in the boots, which explains the low fluid level." "How long have you been experiencing the symptoms?", he asked. "Oh, about a month". "Okay ", he replied, "it's obviously not a bad leak, because if it were, the boots would have blown up like balloons, or split and you'd been leaking fluid everywhere. Since neither has happened, you can safely drive it. I'll just top the fluid, and we can get the parts ordered. We don't normally k/ppep racks in stock...outside of cars that have been in accidents, it's very rare to replace one." Lucky me.

The damage (drumroll, please)...about $1100, including an alignment. The rack is $600, and the remainder of the charge is miscellaneous parts and labor. The rack will be here in two days, but I couldn't get on the schedule until the second week in September. My mechanic is on vacation next week anyway, and all other things being equal, I prefer him to work on the car. Guess we'll wait and see if it gets worse before we have a chance to replace it.

On the drive to work, I yet again began to question the wisdom of keeping a BMW long-term, but in the grand scheme of things, this isn't that bad. Yes, the repair will cost big dollars, but with the newest 3-series equivalent to my car going for about $48K, in reality this translates into about two monthly payments. When I consider the opportunity costs of having to drop $25K on a down payment, combined with a sizeable monthly payment for 4 years, I think I'll take the occasional unexpected maintenance tab.

Update 8.15.04 - New Floor Mats and Wheel Centers

Several years ago I looked into replacing the driver's floor mat because it didn't look so hot, but I decided against it when I learned that I couldn't buy just one mat -- I had to buy the whole set for $125. This week I finally broke down and ordered a new set simply because the driver's mat backing had started to rip and the quarter-turn fastener receptacles bound to the mat weren't holding anymore. The new mats look great, and eliminate the quarter-turn fasteners in favor of a Velcro arrangement, which produces a lot cleaner installation. I definitely recommend buying the BMW cloth mats when it's time.

While asking the parts guys about the cloth mats, I asked about rubber mats. One of the guys said that while BMW doesn't make rubber mats for the E36, the ones designed for the E46 fit pretty well. He added that he had tried the well-known aftermarket brand specially designed for the BMW in his own E36 and found they didn't fit as well as the BMW mats. I asked if I could test fit them before I bought them, he agreed, and...what can I say...for $47 I couldn't pass them up. Right now they're serving as trunk liners (a function they serve very well...they prevent my flight case from thrashing about in the trunk when I turn aggressively) but they'll soon be put into use to protect the carpet when the weather turns crummy this fall. This effort alone should significantly extend the life of the cloth mats, so I figure the rubber mats are worth the extra dollars.

While washing the car recently I noticed the clear laminate on the face of the BMW logo wheel centers peeling away. I also noticed the centers didn't fit particularly well in the rims anymore, perhaps because the rubber lip around the outside edge of the centers had dried out. The parts department was training a new guy, and he initially told me the centers were something like $38 a piece. After they broke out the smelling salts, the guy corrected himself... "oh, sorry, those are $3.75 each". Ah, that's better. Sold X 4!