This past week, I’ve spent a lot of time researching solutions to some problems we were having with Andrea’s car. After the seller tried fixing the vacuum issues affecting the turbo, he disconnected the vacuum line to the turbo wastegate actuator, created a mini vacuum on that line, and plugged it so the turbo actuator was partially closed. He checked the max boost by flooring it in several gears, and the max boost displayed as 15psi. I guess this is at the top end of what is “safe” for the turbo.
Afterwards, everytime the car shifted, it made a loud noise (clunk) and shifted hard. Some intense reading at mercedesshop.com and a few days later, I decided to fix the shifting by diagnosing the vacuum lines going to the transmission. Using a MityVac, I found that the vacuum line going from the vacuum pump to the valves for the turbo/EGT were leaking like crazy, so little or no vacuum was reaching the transmission. I solved this by plugging the line that was leaking. Since that particular line was for the turbo/EGT and the seller plugged the line to the turbo, the line was useless anyway.
With the line plugged, the shifting got much smoother. In fact, the shifting became too soft! Whenever it shifted into higher gears, it would rev a little before dropping rpms. After some more reading, I fixed this new problem by adjusting the vacuum control valve(VCV). The MityVac showed that the transmission was getting approximately 12″ of vacuum and when I revved the engine by pulling on the throttle linkage, it would drop to 5″ or so. I untighted two 10mm bolts on the VCV, turned it clockwise, and retightened. I’m not entirely sure what the twisting of the VCV does, but I’m glad it worked.
Eventually I’ll post a pictures of what I modified and adjusted and update this post.
We filled up Andrea’s car. 391.7 miles and 14.457 gallons = 27.1 mpg. I think the next fill up should give us the true mpgs of her car; this time, I filled up the car until I could see the fuel in the filler tube. Go diesel!
Last night, I changed the oil in Andrea’s car. The seller said that it had about 1000 miles left on it, but I’m glad I didn’t wait. When I checked the dipstick, I noticed the oil was super thick.
I like to use an oil extractor to change the oil on my VW Golf because it’s quick and mess free, but for Andrea’s car, it took me an hour to extract the oil. The oil was just too thick! Earlier in the day, we drove around trying to find a local store that sold an oil extractor that held more than 7L, but no luck. The extractor I currently have only holds 4L; this meant I had to stop half way to empty the extractor and continue. When I stopped half way, the tube accidentally splattered some oil on the wall. So much for mess free!
Over the next free weeks, I’m going to search for an extractor that can hold enough oil for all the cars. These are the most likely candidates:
Pela Pro 14 (14L)
Motive Power Extractor (10 Qt)
MityVac 7400 Fluid Evacuator (7.3L)
I’m leaning towards the first one, since it holds more and looks like it uses a sealed/solid container. I can’t tell from the pictures of the Motive or MityVac products if they also have a solid bottom piece.
Today I stopped by the seller’s house to have him look over the vacuum system, since I found a plugged line while trying to diagnose the power loss. On my drive over, I noticed that the kickdown switch was under the pedal, and needed to be pressed past the point when you think you have the pedal floored. Once I did that, it downshifted fine and had plenty of power.
While at his house, he replaced two vacuum valves and one black vacuum thingy, and fixed some of the vacuum hose connections. It turned out that one of the vacuum lines had a BB in it (from a BB gun?), and some cables weren’t even connected to anything. He mentioned something about Crazy Rays and getting parts there for later, so he can replace the remaining black vacuum thingy. He definitely knows his stuff! Crazy Ray’s looks like an awesome place to get parts for an old car.
He took the leaking injector out and took it apart. One of the metal mating surfaces had a burr or gouge in it, so he filed it down and sanded it and put it back together. After test driving some more, it ended up leaking again, so he found another spare injector and just used the top portion of the spare with the bottom casing of the leaking one. After installing it a second time, the leak was fixed! He showed the injector to me and explained that the nozzles looked like they were new so I can probably hold off on buying new injectors.
The turbo seems like it’s working now and the fuel leak has been fixed, so tomorrow Andrea will be driving it to work!
Here are some photos of the engine bay. One of the injectors seems to have a fuel leak (left to right, top to bottom, seen in the third, fourth, and fifth pic below). Tomorrow I’ll try checking some more references to see what I can do about it. If I need to replace the injector, it’ll cost about $50. The fuel leak is probably related to the power loss, so after I diagnose and fix the vacuum leak and the fuel leak, it should be good to go!
For the little that I’ve test driven this car (Andrea test drove it), I’ve noticed that the car has no power, either from the transmission not down shifting properly, or the turbo providing no boost. There could be several reasons for this, but I suspect the top reason is vacuum related. Below are two images of something I discovered after inspecting obvious vacuum fittings. The junction near the screw on fuel filter has a line that is plugged with a wooden dowel! That means anything downstream from that tube isn’t getting any vacuum. So far the only symptom has been the lack of power and the shifting issue. I spoke with the seller and he’s going to help diagnose the problem on Monday.
Meet Andrea’s new car:
The car is a 1993 Mercedes-Benz 300D 2.5 with 188K miles! The mileage might seem high to most people, but after driving my 2005 VW Golf TDI for 95K miles with zero problems, and after researching the Mercedes diesel engines, I don’t think Andrea will have to worry about the engine failing. Just do a quick search on craigslist and see how many old 1980s/1990s 300Ds are for sale and you’ll see that most are in the 200K+ mile range. It is an old car though, so I’m sure eventually it will have electrical/mechanical issues. For now, it seems great though. Mechanically, everything that I’ve tested is working. When the time comes for repairs, hopefully they’ll be minor enough that I could tackle them. I think the only two things I won’t attempt to do on the car are transmission and engine related.
Andrea has been driving to UMBC on opposite days that I’ve gone, so we’ve been driving to work separately on four of the five work days of the week. Previously, we were splitting the cost of diesel for my car, since we drive everywhere together and my car is super efficient compared to her Oldsmobile Aurora. Because of this, we were saving a lot of money. Now that we drive separately, Andrea has been paying to fill up her Oldsmobile and has been getting really crappy mileage (~18 mpg?). This “new” Mercedes should get her around 30, which should save her a considerable amount of money in the long term.
Go diesels! I hope I hope I hope nothing major happens in the next year or two. That would be super.
In the immediate future, the car will need: new tires, new mirror control switch, and a pillar trim piece. Maybe I’ll also need to check the timing chain, but I need to read more about how to measure the chain stretch.
From what I’ve been reading, there’s no such thing as a cheap Mercedes. We’ll see if that’s true.
