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Old 11-08-2013, 02:55 AM
Left Coast Left Coast is offline
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Join Date: Aug 2005
Location: Oregon
Posts: 314
Mrs. Coast's New Ride

This is going to be a long post, I'm afraid, but hopefully a good story will be the result. Mrs. Coast has driven her somewhat ugly but reliable '83 240D with manual transmission as a commuter for several years now, but a chronic knee problem has lately caused her to favor the '72 coupe with automatic transmission for daily driving. The coupe is beautiful, much more fun to drive, and always was her true love. Sadly, the fuel economy from a 250C is horrendous, and the High School parking lot where she must leave the car all day is not a safe place for a well loved classic with a perfect body. So we recently embarked upon the quest to find a decent (but not too nice) diesel for her every day use.

After some searching, it boiled down to a choice between a non-turbo 2.5 190D (with a sad interior and very bad steering and brakes) and a clean '84 300D (with recent major brake work, a new front end, an AC that blows cold, and a host of other problems). Since neither of us cares much for the tighter quarters of the W201, a low-ball offer was tendered on the 300D and promptly accepted. So now I have the pleasure of bringing back another neglected 300D to respectability. At 290K, it still looks and feels pretty good.

At the starting point: some off the line hesitation, a little smoke, a big enough vacuum leak to make the brake pedal pretty hard and cause semi-functioning door and fuel door locks, a little trouble with the 3-4 shift, and an oily mess under the hood. A really scary looking Lovecraft type setup gave some pause, but the PO was clearly not the type to be messing with grease. He confirmed that he'd never run VO. He thought he'd need the "conversion" to run biodiesel, and evidently some sleaze ball who is probably now in jail was happy to take his $700 to install this useless equipment.

First order of business was to give the engine compartment a good pressure washing, followed up by a good scrub down with strong caustic cleaner and a thorough rinse. After a good cleaning, I can confirm that there is indeed an engine under the hood, and everything looks to be hooked up. Next up: yanking out the Lovecraft type junk and restoration of the fuel system to the original configuration. Nothing but diesel fuel in the big glass water separator filter. That's a relief. PO's records indicated that the last valve adjustment was performed at 270K, so might as well go there next. All valves were tight, but not too bad. Chain rail looks OK, and chain checks out good enough to leave it for now. Hot or cold, there is not enough blowby to make the cap move at all, and there is zero engine rock. Oil pressure went to 2 bar at idle after a 50 mile run. The oil cooler hoses are a year old and genuine MB.

So far I'm liking what I see, except for that smoke and hesitation. So out come the injectors. At that point, a compression test seems like a good idea. Results are encouraging, with readings between 420 and 430 in all of the holes. The injectors look like the originals to me, though that turns out to be not exactly the case. Several days later, Mark (aka Greazzer in these pages) informs me, in gentlemanly terms, that they are among the worst he has seen. I receive the rebuilds several days after that. I'm not even sure that these are the same injector bodies, but they sure look good. (For anyone that needs injector service, it would be a mistake not to send them to this guy. He is prompt, communicative, and very reasonable. He's one of that disappearing breed of craftsmen that maintains standards and will do whatever it takes to get the job done right.)

In the down time, I've found a bad vacuum actuator behind the heater box, and a couple of other leaky ones in impossible places. These are going to be a challenge to sort out without taking out the dash. Fuel door actuator is toast. With the green vacuum line for the ACC system isolated and a couple of tees plugging off the fuel door lines, the vacuum reservoir holds well, and the door locks will cycle a half dozen times on the reserve. I'd rather have had a couple of bad door locks, but that's the way it goes sometimes.

Today I found time to install the newly rebuilt injectors, The engine fired up while I was still bleeding hard lines. I clumsily managed to snap the plastic tee off the brake booster line, so now I have something to spend the PNP credit that's been in my wallet for six months on. Between the new injectors and dealing with a few worn linkage parts, the hesitation off idle is virtually gone and the pedal feels a lot better. Still a little smoke at the tailpipe, and I noticed that some air is showing up in the line between the lift pump and the fuel filter stand, so there's more to be done there.

I'll change the transmission filter and fluid next week, and then investigate the vacuum modulator situation. Shifts are smooth, maybe a little late. The biggest concern is a downshift from 4 to 3 when I let off the pedal. This will be a bigger concern if it still occurs after I'm satisfied that everything is right in the fuel delivery department.

I suppose that we will end up with a little more into this car than we would have if I'd just picked up one of the plentiful old Volvo's that can be found on every block in Portland. That would have been the farthest that the Mrs. would have gone as a compromise, and she would not have been happy. She is the real MB enthusiast in the family, and she doesn't want to drive anything but a W115 or a W123. I've long understood that my function in life is to give her whatever her heart desires. I'll post more as this project progresses, which will happen as time allows over the coming weeks.
'79 240D
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