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Monday, June 24, 2024

Doug's Domain

Doug Vetter, ATP/CFI

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Saturday, March 24, 2018

Third Oil Service

Since the vehicle spent the better part of two months in the body shop this winter I had to delay the third oil service a bit. However, with the car back in my possession and temperatures hovering in the upper 50s I was able to tackle this process about a month ago (February 26) with 995 miles on the clock since the last oil service and 1557 miles since the overhaul.

The oil turned out to be darker or more opaque than last time, which is to be expected. While I did see some fine metallic particles in the drain pan this time around the amount was far less than the last two oil services, and that's really good news, as it shows -- at a high level, anyway -- that wear associated with break-in has diminished. I expect perhaps one or two more oil changes will be needed to completely flush out all the wear metals from the system.

(Image: Third oil service analysis)

After the oil drained for a good 30 seconds I took an oil sample and sent it to Blackstone. I had just recently ordered a new batch of containers from them and these came with a prepaid USPS shipping label. While this meant I did not have to pay the extra $5 or so I have typically paid for priority mail, there is no free lunch, as Blackstone raised the cost of their samples again to $28, no doubt as required to cover the cost of shipping.

I expected the delivery to take about a week and figured I'd see the report a few days after that but unfortunately it took nearly a month. Based on a long history with Blackstone I'm sure this was not their fault. Most likely, the package wallowed in the USPS delivery network for a bulk of that time. I may use the "free shipping" method one more time to see if this was a fluke, and if not I will have to recommend Blackstone provide a reduced sample cost for those who want to pay for their own (expedited) shipping method.

I originally assumed that the shiny metal I saw during the earlier oil changes was aluminum. Based on this report, however, I'm fairly confident it was iron. This is something of a relief, since I was concerned that the cam trays or pistons themselves might have been to blame. This bodes well for the future of the engine and the top end in particular. However, I'm not out of the woods yet.

All of the wear metal sample quantities need to multiplied by roughly 5 to normalize the data with respect to my unit averages. This means the already high 29 PPM iron turns into a whopping 145 PPM and the 4 PPM aluminum turns into a more respectable (but still high) 20 PPM. The upside is lead, one of the two wear metals that started this whole overhaul train running, is now so low as to be "in the noise", so to speak. If I normalize the lead number I arrive at a mere 5 PPM, which is 20-25% of the original, pre-overhaul value. I think it's safe to say that the bearings are in good shape and have suffered very little if any wear during the break-in process. Strangely, copper is also somewhat high (8 PPM, 40 PPM normalized). Copper is usually a component in bearing metals or bushings. Given the low lead value it is unlikely to be coming from the main or rod bearings, so that leaves the rod bushings as the most likely source.

Based on these results I expect to do an oil service and sample again in 1000 miles. If the numbers look a lot better (as I expect they will) then I may increase the interval to 2000 miles, but given how little I'm driving the vehicle of late I may wind up doing it based on calendar time regardless.

Driver's Door Lock Linkage Failure

Just after the new year I was summoned to jury duty for the first time in my life and forced to travel a couple days to the county court to sit in jury selection. On the first day I was ultimately selected for an automobile accident case where one guy rammed into the back of another car, causing the other driver to sustain back injuries. As the case was described I became interested in hearing the testimony of the expert witnesses. Ultimately, however, on the second day I was dismissed from the case because I revealed during the jury selection process I had been in a car accident when I was 15 and was the beneficiary of a related settlement.

Since I had been forced to travel in poor weather on the first day the car became filthy. That meant I couldn't put the cover on the vehicle to protect it from the freezing rain forecast that evening. Predictably, the next morning I walked out the door to find the vehicle doing a decent impression of an ice cube. I pulled the driver side door handle up once, breaking the ice covering it, and that caused the vehicle to wake up and the lock heater to turn on. I gave the heater thirty seconds to work and then inserted the key into the lock. The good news is the lock cylinder accepted my key and turned freely at that point. The bad news is that as the key turned I heard the sound of something snapping and then dropping down into the bottom of the door, at which point the key spun 360 degrees while the vehicle remained locked.

I ultimately walked to the back of the vehicle, inserted my key into the trunk lock and managed to turn that to electrically unlock the vehicle. I briefly questioned my decision 20 years ago to avoid paying $500 for the alarm system that enabled keyless entry but dispensed with that thought process once I realized the vehicle was open. I was able to fire up the engine, get all of the defrosters working, and slowly drive away as the remainder of the vehicle thawed out.

It didn't take me long to surmise what had likely happened. While the vast majority of the door lock components are made from metal as they should be, the last time I took the door apart I noticed BMW stupidly decided to use a small plastic bushing of sorts to connect an operating rod between the lock cylinder and door lock mechanism. My assumption at this point was that the bushing simply snapped due to the cold or possibly because it had trapped some moisture that froze overnight and it could not move / rotate freely.

I have not been able to find the part in the ETK so it may be provided only as part of the door pull / lock assembly. If that's the case I may need to have an equivalent part machined out of delrin or something, because I sure as hell will do everything possible to avoid paying BMW's ransom for a new door pull assembly to replace a part worth at most 50 cents. My hope is that the fragments of the bushing are still in the bottom of the door and will be in sufficiently good shape (i.e. in as few pieces as possible) to serve as a prototype for a new, more robust part.

Next Up

The next maintenance task will involve swapping my winter tires for summer rubber. After that I'll take apart the driver's door and come up with a solution to fix the lock mechanism. Stay tuned.