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Friday, July 25, 2014

Doug's Domain

Doug Vetter, ATP/CFI

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Friday, January 5, 2007

Body Shop Progress

Like most families, mine gathers to pig out on New Years Day (literally...we had ham AND turkey!) As luck would have it, the body shop I chose to do the work on the E36 (same one I used last year for the second deer hit) happens to be within about 20 minutes of my uncle's place and a BMW dealer. Since my brother and I were headed to the same place that day he offered to help me drop the car off at the shop so they could start the work necessary to repair the sidewipe damage first thing in the morning.

The shop is about 45 minutes away from my home and I normally wouldn't have been able to get up there to see the work in progress but my brother happened to be in the area yesterday and managed to take a few snaps I thought you might want to see. Like I've said before, body work is a messy business, which explains why I put the OE wheels back on the car. I think that makes a total of five (5) swaps of these wheels over the last month or so, but who's counting, right?

I decided to repaint only the driver's door and blend into the front and rear quarter panels, as well as replace the skirt and both side view mirror covers. The right side mirror cover was not involved in the incident, but it was never prepped properly by the original shop so its paint had started to flake off. Since it's a no-brainer to paint it while he has the paint mixed for this job, I decided to spring for it now. The right side door will, unfortunately, retain the blemishes of the first paint job, but repainting it would have cost another $1500 and that's money I'll need for more critical work (see below).

The last shop to work on the driver's door didn't take the time to remove the door handle trim, so they masked around it -- or I should say, they attempted to mask around it. Two corners were clearly painted over and it always irritated me that they didn't take the time to do the job right. This shop's owner knows me well enough that during the initial quote he assumed I'd want the trim removed and just asked if I wanted to replace it with a new piece. The trim's rubber gasket had a few cracks in it (a common problem on these cars as they age), so since it only cost $12 and would save me the hassle of doing it myself later I told him to go ahead with it.

Removal of this trim piece on the coupe requires removal of the door panel, since a small piece of metal blocks access to the "slider" release mechanism through the edge of the door, so I removed the door panel before dropping the car off at the shop. Normally, I'd let the shop take care of this, but I had to remove the door panel anyway to fix a few things. The annoying thing is that as careful as I tried to be, the upper door panel retainer pieces broke free from the door panel again so I have to reaffix them OR replace the door panel. And while I'd welcome the cosmetic enhancement of a new door panel (mine has more than a few scuffs on it), I'm not sure I am prepared to stomach the $500 bill for the new part.

Hopefully the vehicle will be ready for pickup sometime next week so I can get started on other work, like the Check Engine light diagnosis.

Check Engine Again

The day before I brought the car in the check engine light illuminated again and all I could think was "oh well, here we go again". The problem has clearly grown worse, so I probably do need new catalytic converters, but I'm planning to approach the solution slowly so I don't spend money needlessly.

I know all four oxygen sensors are original, and at 140K miles they should be replaced, however I don't want to bother installing oxygen sensors in the mid-section if I'm just going to pull it down later.. The first step, therefore, will be to replace the pre-cat sensors located in the headers. The connectors for those sensors are located under the engine covers and I'm planning to have the covers off to do other engine work, so I plan to do the oxygen sensors at that time.

There is no particularly inexpensive aftermarket alternative for the OE oxygen sensors so I'll likely pay around $150 each, or $300 now and $300 when I do the mid-section (which is $1500 in itself).

Saturday, January 13, 2007

Car Returns from Body Shop

Wednesday afternoon, or seven business days since I dropped the car off at the body shop, the owner called to let me know the car was done. My brother offered to make the 45 minute run to the shop late that night. Of course, the pickup wasn't without its snags.

First of all, I arrived to find the car filthy. Even in near pitch black conditions I could see dust over everything and a lot of fine scratches in the clear surrounding the repaired area. I assumed the car wasn't washed because after several weeks of well-above-average temperatures we had a 24 hour cold snap and it was near freezing the entire day. I also figured that some Menzerna finishing polish and my Porter Cable orbital polisher would be enough to remove the fine scratches, so I considered this a non-issue.

The shop owner noticed the Check Engine light and asked me if I wanted him to clear it using his diagnostic system, and I agreed, because I figured it would save me a trip to see my tech. Afer I turned the key and the warning lights in the gauge cluster went out I found the Check Engine light dark as expected, but I was surprised to find the airbag warning light glowing bright red in its place. I assume the warning was tripped because the shop may have had to disconnect the airbag to get the door panel insulation out of the way while R&R'ing the door handle trim.

Why, exactly, the shop's analyzer wasn't able to clear this code is beyond me, but it's true to say that unless you have a BMW OEM analyzer like the GT1 at your disposal, you're working with a reverse-engineered solution, and they never work exactly as expected. Fortunately, in this case the airbag warning is merely an indication that the system has been tampered with and does not mean that the system is disabled as a whole. Even with the airbag warning light illuminated, any airbags still connected and in good working order will fire if commanded. I had planned to take the car to my tech the following morning to clear the Check Engine light anyway, so I this really didn't change anything. I accepted the car.

My brother had brought his '01 E39 530 out for the trip, so when traffic permitted, we took the cars into their element. After nearly 45 minutes of driving on all types of roads, from local country twisties to high speed straights on the interstate, I came away convinced that the car drove better than it had in years. The results of the swaybar service weren't the product of my imagination after all.

Get by with a little help from the BMW GT1 Analyzer

When I arrived at my dealer the following morning, I found my technician working to repair the top of a new Imola Red MZ4 roadster -- the same model roadster I flogged at Spartanburg last year. Apparently it's top refused to lock properly and had blown open at speed. Not exactly a problem I'd care to have in a $50K+ car but these things happen in the first few years of a new model (which explains why I buy at the end of the model run, but that's neither here nor there).

While I waited for him to finish, I peered over his shoulder and watched in amazement as the GT1 diagnostics analyzer displayed the state of the top in real time as it went through its motions. I mean, damn. EVERYTHING on these cars is monitored by the computers, and those computers talk to the GT1 with a verbosity that makes aftermarket analyzers look like children's toys. There's no way in hell you'd get that kind of information from any aftermarket analyzer, simply because BMW considers anything beyond the standard OBD II interface proprietary.

"How much is a GT1?", I queried. He lamented, "about eleven grand, but you don't want this one...BMW is coming out with a new tablet system in about 18 months.", as if to imply that I could justify buying one. I mean, I do have a hand in maintaining three BMWs now, but something tells me I'd have to service a lot more to justify that cost. Maybe if I wind up opening a BMW / Porsche shop (that is to say, after I buy a Porsche) I can justify all the cool toys. :-)

In any case, I explained the fault light situation to my tech and he told me to bring the car around to the bay so he could clear the fault codes for me. About five minutes later, we disconnected the GT1 and the job was done. The gauge cluster was refreshingly free of warning indicators and I was quickly on my way to work. Sure beat having to go through the normal channels to have this minor issue cleared up. Have I said lately that my tech is a cool guy?

Working by the Warmth of a Kerosene Heater

That night, I decided to get the car back into form quickly and tackle several tasks:

(Image: Comparison of old and new E36 microfilter)I raced home as I watched the outside air temperature gauge creep toward the freezing mark because I knew that I needed to wash the car before I did anything else. After I finished flirting with frostbite, I pulled the car into the garage, fired up a kerosene heater I keep around for such occasions and got to work.

While polishing the vehicle I soon realized that some of the surface dust wasn't just dirt. It was overspray. And there was a LOT of it. In fact, while the finishing polish successfully removed the surface grit and fine scratches, some overspray remained. I attributed that to the fact that I was using a very fine finish polish and not a more aggressive cutting polish as normally specified for the task. This would do for now, I reasoned, so I applied some Menzerna FMJ to protect the finish and then took care of the other tasks. I finished around 11PM and slept the sleep of the victorious.

Microfilter Replacement

As the owner of any recent BMW should be aware, the cars come with a fine particulate interior air filter. These filters are fine enough that they need to be replaced on a regular basis. For the E36, BMW recommends every 15K miles, and that has proven to be a rational interval in my experience.

I originally planned to replace the microfilter during the holiday break, but soon realized it made little sense to do that and then contaminate the filter with body shop dust which smells like...well...a body shop, so I postponed the task -- until this morning.

Rather than spew about that here, I figured I'd write up a DIY article on it. What I will say is that I'm glad this job doesn't have to be done but once every 15K miles, because it's a royal pain in the ass. I can also say that I'm glad that BMW fixed this abortion of a design in the E46 -- it's microfilter is simple to replace by comparison. Look for the article soon.

Mileage: 137890, Parts: $27, Labor Saved: $50

Sunday, January 21, 2007

Tensioner Pulley Bearing Failure

Last Monday I started the car to go to work and I heard a muffled rattling noise from the front of the vehicle. I can best describe it as the sound that might be produced by a couple ball bearings rattling around in a foam-lined can. The sound was intermittent, but occurred often enough to allow me to localize the source to somewhere around the oil filter cannister. The first thing that ran through my mind was bad bearings of some sort, but I couldn't tell exactly what was causing it. Since it was raining, I turned on the lights before I pulled out of my driveway and I noticed the sound became more pronounced and nearly continuous. At that point I figured the alternator bearings were on the way out.

The engine was running smoothly and there were no warning lights illuminated on the dash, but I figured I'd play it safe and drop by the dealer to see my tech. He agreed to leave his nice, warm shop and brave the weather with a smile to help me isolate the problem. It didn't take long for his tuned ear to suggest "sounds like a problem with one of the belt pulleys". He then grabbed a can of brake cleaner and a long (12" shank) screwdriver and asked me to start the car and turn on the headlights and the A/C. Once again that made the sound much more obvious and nearly continuous. He sprayed the cleaner on a few of the larger pullies but that didn't do anything, so he grabbed the screwdriver, carefully laid the tip on a few of the engine parts and put the handle to his ear, thus creating a crude but effective technician's stethoscope.

(Image: Closeup of failed tensioner pulley)As he carefully routed the tip of the screwdriver onto the main drive belt tensioner it began to vibrate in concert with the offensive sound. He handed the handle of the screwdriver over to me and I felt the screwdriver jumping up and down as the tensioner bucked from the change in bearing load. Sure enough, the main belt tensioner pulley bearings were on their way out.

I breathed a sigh of relief at the prospect of an easy (read: inexpensive) repair, particularly since I knew I'd get the replacement part for free under warranty. I'd replaced this very pulley during the cooling system overhaul last year. My tech said he was booked for the day so if I wanted him to do the work I'd need to bring it back to him, but I offered that I'd try to do it myself and call him with any questions.

Fast forward to Saturday. I brought the car into the garage, fired up the kerosene heater again, and got to work. About an hour later, I had the new pulley back on and had run up the engine. It's completely silent now. On a scale of 1 to infinity, this is a one-curse job (I only let out one curse due to crampt space in which I had to work), so it's a pretty reasonable task for the DIYer. This job is identical to that required to replace the belts, so I'll document that later in a DIY article.

When I took a closer look at the old bearing there wasn't any obvious damage to the bearing races like bluing of the metal due to heat stress. In fact, there were only a few differences of note:

How long could I have run the bearing before it failed? I really don't know, but since a failure of this bearing might cause the belt to come off, and that could cause some real damage to stuff like my brand-new radiator, I wasn't about to test that boundary. For what it's worth, the sound did become noticeably worse over the course of the week, so I imagine this is a task best taken care of in that timeframe.

More Tools

I went to Eppys again today to pick up some tools.

Lesson learned: never put your mirror tool in the same toolkit with other loose tools. Fortunatley, the old one was actually a magnet / mirror combo, so it will live on as a magnet tool. I decided to buy a dedicated mirror tool since it was slightly cheaper and that's the one I used to do the pulley repair.

I have to admit that I take most of what my 30 year BMW technician says as the gospel, but I was always a bit skeptical of the technique he taught me to R&R the engine driven fan. Somehow just tapping on the end of a wrench didn't seem like the right thing to do, so I bought a $32 generic tool designed to hold the water pump steady by grabbing the bolts that hold the pulley on. I never took it out of the original packaging as my technician's technique worked. I plan to return the tool. Summary: all you need to R&R the engine driven fan is a large 32mm wrench...and it doesn't even need to be a "thin" wrench.

In prep for the valve cover work, which requires a very light torque, I decided to spring for the smallest torque wrench SK offers. I recently saw the result of an improperly-installed valve cover gasket on my brother's 530. It's a long story -- and no, I didn't have anything to do with it aside from getting my tech to fix it the right way -- but it was a $275 job. If I do the valve cover gasket myself, that job will pay for the torque wrench and then some.

Mileage: 138450, Parts: $0 ($45 part covered under warranty), Labor Saved: $110, Tools: $210

Monday, January 22, 2007

Spoke Too Soon -- Replaced the Tensioner

Remember yesterday when I told you that the pulley was "completely silent"? Well, I was wrong. The next morning I came out to start the car, and ran inside to get something I forgot. By the time I came back out five minutes later the noise had returned and it was worse than it was previously -- it was now continuous even without any appreciable electrical load. I quickly decided that the real cause of the noise was the tensioner itself. Some brief surfing on bimmerforums and e46fanatics confirmed the correct diagnosis. The only problem? If you want the tensioner, BMW only sells it with the pulley, so I now have a spare pulley.

(Image: Failed accessory belt tensioner) I picked up the tensioner at my dealer this morning and installed it tonight. After the first run through on Saturday, I found this procedure to be old hat and had the job done in 30 minutes including some searching for proper torque specs. And speaking of specs, I'll relate the fact that the two tensioner mounting bolts are cad plated (the TIS calls these "yellow" bolts) M8x35 8.8 hardness and the generic torque spec of 24 Nm or 17 ft-lbs applies. To gain access to the top tensioner mounting bolt I had to remove the offset pulley which shares a mounting bolt with the alternator. That's zinc plated ("silver"), M10x150, 8.8 hardness and should be 40 Nm or 30 ft-lbs. I've gained enough experience to recognize approximate torque values when I loosen things and these specs jived with the force required to loosen them. As with everything from this site, however, use them at your own risk. If you snap a bolt, don't blame me.

The one thing I hate about this job, incidentally, is having to deal with the main drive belt. I feel like a monkey f*cking a football trying to get that thing routed correctly and the tensioner hauled back enough to get the belt over the tensioner pulley, but that's why I pay myself the big bucks. I saved about $150 in labor doing this myself.

Parts Order

I placed an order with Jason @ Tischer BMW today for the power steering system overhaul, the right side exterior door handle trim (to match the left side put on by the body shop) and some miscellaneous hardware. I wanted to order the tensioner from Jason to save some coin but felt I should replace that ASAP. Fortunately, my dealer had it in stock so I picked it up there. With "urgent" repairs there's really no choice. I wasn't about to save $20 and put some very expensive components at risk.

Mileage: 138550, Parts: $80, Labor Saved: $150

Wednesday, January 31, 2007

Emissions Woes

Last weekend I was on my way back from lunch when the Check Engine light illuminated again. I didn't need to connect the GT1 to know why. This car has had a long history of storing codes about the bank 2 (cylinders 4,5 and 6) catalyst efficiency, but it wasn't until last year that it started to trip the check engine light (CEL) on a steadily increasing basis. Last weekend's event was a mere three weeks from the last event, and I wasn't interested in dealing with the aggravation of running to my dealer and bugging my technician to clear the code every five minutes, so after my tech cleared the codes yet again Monday morning I committed myself to come up with a permanent solution for this problem -- a solution that would require a lot of research.

The post-1996 (OBD II) 328is exhaust system utilizes the tubular stainless steel headers and mid-section from the M3 to provide a dual exhaust configuration. Dual exhaust is great from a performance perspective because it lets the engine breathe, but it hurts the wallet when it comes time to replace emissions components because there's two of everything. Each pipe has an oxygen sensor positioned in the header that controls the fuel mixture, a catalytic converter that helps reduce harmful emissions, a second oxygen sensor to verify how well the catalyst is doing its job, and a resonator to reduce noise and tune the exhaust note. Only at the muffler are the exhaust gases recombined to reduce noise to conforming levels.

The catalyst efficiency code results when the second / downstream oxygen sensor reports the emissions are out of the acceptable range and thus the cat isn't doing its job. Failure of an oxygen sensor or its integral heater element triggers its own code, so I'm about 90% sure at this point that I need to replace the cats. They come as a unit with the mid-section, so I'm really looking at replacing a major exhaust component, the retail price for which is $2000. Fortunately, Jason at Tischer BMW quoted a far more reasonable price, but $1500 and change is a huge nut to crack.

There is a small chance that I may not need to replace the cats, however. The cat efficiency warning can be triggered if the engine is running rich enough that the cats can't keep up. I was once told that oxygen sensors either work or they don't, but further research revealed that as oxygen sensors age they effectively report a leaner mixture than is actually occurring. Since the BMW DME relies on the output of the pre-cat oxygen sensor, my theory is that by replacing the pre-cat oxygen sensors I can get the mixture back to spec again and reduce the amount of combustion byproducts that are plugging up the cats and causing the decrease in efficiency. It may be too little, too late, but it's worth a try since they're already 38K miles past their recommended service interval and need to be replaced anyway.

Oxygen Sensor Supply Chain

(Image: New BMW oxygen sensor)So when I began to look for new oxygen sensors I checked realoem.com for a part number and price. It turns out that until a build date of 4/98 (shortly after my car was produced) all four oxygen sensors are the same: BMW part number 11781427884. This part has the notation "SIEMENS/L=990" in the description. Siemens, of course, is the manufacturer of the part and research revealed that L means the length of the lead. 990mm is 38 inches, or a bit over three feet, which is clearly the length needed to reach from the top of the engine, near the fuel rail where the pre-cat sensor plugs are, to the headers. The obvious downside to the BMW part was the price -- $195 on a somewhat outdated realoem price book (the actual price is closer to $225 now), so I went in search for aftermarket sensors. This was an educational experience, let me tell you.

The first thing I learned is that there are two types of oxygen sensors available in the aftermarket. The type required by the Bosch DME is the titania sensor. So, if you do decide to buy aftermarket sensors or are intent on trying to fit a universal sensor to this car (that practice is actually discouraged by many DIYers), no matter what you buy, you must make sure they're of this type. If you don't, at the very least the car will run like crap and you'll be out the cost of the sensor.

The second thing I learned is that while Siemens or Bosch are technically listed as the parts supplier on BMW's ETK, the sensors are actually made by NTK -- a Japanese company. This is no surprise, really. Siemens and Bosch are smart enough to realize that they can't build everything themselves and they source parts from other manufacturers just like BMW does. The problem comes in when you add one or more tiers of profit margin onto an otherwise reasonably priced sensor -- it gets expensive very quickly.

NTK actually makes the sensor (NTK part number 25013) and sells it for about $80 in the aftermarket (courtesy of bimmerparts.com). They also sell the sensor to Siemens and Bosch (Bosch part number 13844), who then turn around and retail it for about $110 under their respective names (courtesy of bavauto.com). BMW contracts with Bosch to provide the BMW OE part with their logo stamped on it, but as all automotive companies do, they tack on about 100% margin. This results in the $225 retail price that you or I would pay at the dealer's parts desk.

At this point I wondered if I could really trust the NTK sensor to be identical in function to the Siemens / OE sensor so I went in search of user feedback. Sure enough, I found several reports of the NTK 25013 parts failing prematurely. Now, I know full well that the supply chain works in such a way that the parts that meet OE specs are sold to the OE, while parts that don't necessarily meet that spec but are otherwise marketable are sold in the aftermarket, so it wouldn't surprise me that NTK plays this game as well. But since a failed pre-cat sensor causes the engine to run rough and can damage the cats, while failed post-cat sensors simply trip codes, I didn't want to take a chance here. I ultimately decided to buy the OE sensors from Tischer (at $155 each) and see if they were stamped with NTK as some people said they were. The sensors arrived today and I hastily opened the box to find my new sensor that had the familar BMW logo stamped on it...right next to those of Siemens and NTK.

So, I think it's safe to say at this point that NTK is the sensor OEM and Siemens just reboxes them for BMW, but I'm not 100% confident that they are the same exact sensor made to the same quality standards. If you want to save $60 a sensor, you're welcome to test that theory, but for me, I'll stick with the OE sensor for the pre-cat application so I don't give BMW any excuses to deny warranty coverage for the new cat when or if it's installed. I am, however, more than likely to go for the NTK or Bosch branded parts for the post-cat units. I'll be pissed if they fail prematurely, that's for sure, but at least I won't be pissed that they destroyed my $1600 mid-section or left me on the side of the road with a rough running engine.

Mileage: 138800