Saturday, July 14, 2007

It's been pretty quiet on the BMW front lately...and that's no surprise given the money I've thrown at the car in the last couple years. I expect the lull in scheduled maintenance to continue until the struts are due later this year. That's not to say I don't have a good share of cosmetic work still in the pipeline, but it's non-essential so it will get done when I have the time and money to spend on it.

Oil Service

The oil service indicator illuminated this week within a couple hundred miles of my estimated oil change interval, so I bought the supplies this week and changed the oil today after 4405 miles. Since Blackstone sent me a couple of sample kits shortly after my last analysis and I continue to save considerable money doing the work myself, I decided to do another oil sample. I found the oil in the drain pan pitch black as ever, but I should know the true state of the oil later in the week when the analysis results come in.

Carpet Cleaning

As surprising as it may sound, I've never cleaned my carpet. I have simply used floor mats to keep a bulk of the grunge off of them and used the vacuum on a regular basis. And truth be told, the carpets still look new. A few weeks ago, however, I discovered a Bissel carpet extraction machine in my brother's basement so I grabbed it to see if I could breathe some life into my old carpet.

I've become a fan of 303 Aerospace Protectant as a replacement for Armor All, so I bought a container of their concentrated carpet cleaning solution for this job. The recommended dilution is 10:1 but I diluted it to about 20:1 because extractor machines can cause foaming. I filled up the machine and within about 30 minutes had cleaned the entire carpet as well as my carpeted floor mats..

The general technique is to apply the solution with the extractor's wand, scrub it with a brush and then use the vacuum suction to pull the moisture back out of the carpet along with the dirt. However, under the best of circumstances, this process puts far more moisture into the carpet than it extracts, so I left the car out in direct sun on a hot day with the windows open.. When I came back a few hours later the carpets were perfectly dry as well as perceptably cleaner and fresher smelling -- so much so, in fact, that I've decided not to replace the carpet after all.

The extracted liquid was dark gray and disgusting enough that I felt the job was worth the effort, but I am planning to do this only on an as-needed basis rather than some set interval.

Mileage: 146440, Parts & Shipping: $65, Labor Saved: $80.

Friday, July 20, 2007

Oil Analysis Results

The oil analysis results pretty much speak for themselves. I'd like to get this engine to 250K before I retire it and if my only concern were simple wear metals I'd say this data indicates I have a shot at meeting that goal.

Of course, the whole point of starting oil analysis was to track fuel or coolant in the oil, which could indicate any number of problems that if left alone could cause catastrophic engine damage. The report again mentions the high viscosity of BMW oil, but as I've said earlier this is normal and expected as BMW 5W/30 is really closer to a 5W/40 by design.

When I get a few more samples under my belt, I plan to import this data into a spreadsheet I use for aircraft engines to track and graph the trends. I'll publish that spreadsheet if there's sufficient interest.

Faint Front Wheel Noises

A few times I've pulled out of the driveway recently I've noticed a very faint rhythmic growl coming from the front right corner of the vehicle when making gradual left turns at a relatively low speed (< 30MPH).. That could be a lot of things, but it's most likely the tire or the wheel bearing. Since the tires are only 6 months old and in pretty good shape, while the wheel bearings have almost 150K miles on them, I'm putting my money on the latter.

Replacement of the front wheel bearings costs about $500 a wheel at the dealer, so there's a lot of built-in motivation to do the work myself. The job is easily within the realm of a DIYer with my limited experience, but the task doesn't come without downsides. If everything goes as planned, I can do this job with little more than a breaker bar and a huge (46mm) socket. If things go awry, on the other hand, I'll need access to some specialized tools that are fairly pricey for the DIYer. Fortunately, I happen to know a cool technician that has offered to let me borrow whatever BMW tools I need.

Steering Wheel Noise

It's been faint for years, but now I have a pretty persistent, repeatable scraping noise coming from what appears to be the left side of the steering wheel. I've heard this can be the result of bearing wear in the steering column, but the sound happens at the same point in the arc as I turn the wheel. My technician hinted that this might be due to the wire spring (presumably in the slip ring component) that connects the airbag to the car's systems. Apparently, while the horn uses a circular contact and wiper arm / brush arrangement to maintain electrical contact when the wheel is turned, the airbag's wiring is more critical and is thus routed through a permanent connection in the form of a wire spring that winds up as the wheel is turned from the center position. As the tension in the spring increases, it can deflect and rub / scrape against something.

I believe the solution to the problem will be replacement of the slip ring. I believe you can order the slip ring assembly by itself, but I know that if you buy the wheel you get one by default. As I had plans to replace the wheel eventually due to some cosmetic damage to the leather (the result of nine+ years of normal and expected wear and tear), it makes sense to buy the wheel now. That, however, presents me with two options:

• Replace the four spoke wheel with another and keep my existing airbag. This is the cheapest solution because while the wheel is reasonably priced at slightly less than $300 with Tischer's discount, I have to buy the airbag locally (with a lower discount + tax, or a cost of $700) because BMW dealers won't ship airbags to end customers for some reason. If I go this route, the risk is that the new leather on the wheel and the "seasoned" surface of the airbag will be sufficiently different that it will look like crap. On the other hand, I have 700 reasons to take the chance and see how it goes. Worst case? I replace the airbag too, eventually.
• Replace the four spoke wheel with the 3 spoke wheel that came on this car in the 1999 model year as part of the M-Technic package. This is the same wheel that came on the 96+ M3 and, I believe, the Z3 models. It's a bit smaller in diameter, a bit thicker and, surprisingly, about $50 less expensive than the four spoke wheel. The snag is the airbag is not interchangeable with the four spoke so if I go this route I must replace the airbag at the same time.

While airbags have no specified life limit that I'm aware of, I recall reading that when airbags where first conceived they were designed to last 10 years. Since I'm almost at that point, it seems foolish not to upgrade it so it actually does what it should do in the event of a crash (you'd be surprised at the number of airbags that simply don't deploy for one reason or another). On the other hand, I absolutely hate the idea of spending $1K on a freakin' steering wheel and airbag, but something tells me the sting of that expense won't seem as bad if I consider it an "upgrade" as well as a "fix". I have yet to decide what to do, but you'll see the results here, I can assure you.

Mileage: 446600