1985 300D

[Amanitas]

So, a while back I purchased a 1985 300D. It was in pretty good shape overall mechanically... the engine and tranny were both sound. The owner of the car had picked it up from an engineer at Yale who did a WVO conversion... a homebrew version. It looked good though! The tank and lines were good, though not the way I would have done it. Oh well, it worked.

But, the guy I bought it from didn't take care of the WVO properly, so gunk got all in the lines. And, the purge cycle wasn't done properly so WVO got into the diesel tank. Over time, it stopped running right. I put it in the shop (since I don't have my own space and tools yet), and they cleaned out the lines and tank... but re-plumbed the feed and return lines wrong... I found out later they were done in reverse.

So, I sold the car to a group who was doing a special alternative fuel program at a local tech school for diesel mechanics. I figure, good car for them to work on and learn from.

I got an email the other day saying the program was over, and I was asked if I wanted to buy the car back. They apparently have it plumbed correctly now, and it's gone 1500 miles with no issued. So, I'm excited.

My questions to you all are:

1) What kinds of things should I inspect when I go take a look?
2) Do you know of any specific issues this car may have, overall?
3) How much of a following does the M-B diesel really have on here?

Thanks!

 

[The Warden]

Is it a CA emissions car?

A CA emissions car will have a trap oxidizer in the exhaust which can cause issues...however, the good news is, it's still covered under a recall, and if they find that the trap oxidizer caused damage to your turbo, they'll replace the turbo for you

Beyond that, really, you'll want to look for the usual things...pull the oil filler cap with the engine running and make sure there isn't excessive blowby (although some blowby is expected and normal), check for excessive play in the turbo shaft, etc. You'll also want to make sure that the cooling system is full...this is an issue that killed a fellow member's engine recently the best way to do it is to park the car so that the front end's as high as possible, and wait for the engine to cool down. Then, remove the small rubber hose that goes between the top of the radiator and the top of the expansion tank, at the expansion tank, and hold it up as high as possible. Then, squeeze the upper radiator hose and, before releasing, plug the end of the small hose with your thumb. While plugging the small hose, release the big hose...and remove your thumb from the small hose, squeeze again, plug, release, etc until coolant starts to come out of the little hose. This SHOULD get MOST of the air out of the system...what you're doing is displacing air and pulling coolant in from the expansion tank to replace the air. It's a PITA, but it's really the best way for a DIY to do it.

Otherwise, assuming the engine sounds happy and the tranny shifts okay, you should be good to go...you might check the condition of the tires, see how the suspension feels, and I would also take a lug wrench and see if the front wheel shifts any. If it shifts aft at all, the guide rod mounts are probably bad...not a huge deal to replace, but can be a pain. I would also do a valve adjustment and check the timing chain stretch, but that's probably best left until after you've gotten the car home. There are also various body drains to clean that, if neglected, can lead to water inside the cabin

FWIW I contend that '85 is the best model year for the 123...it has a 2.88 rear end instead of the 3.07 rear end used in earlier cars, which helps with freeway cruising and fuel economy. Also, various things (i.e. the tach pickup) were changed to a setup that's more bulletproof than the earlier cars.

Hope this helps...good luck and congrats on getting her back! There are a few people with M-B's who also own IDI's, although this forum doesn't see nearly as much traffic as the IDI board. Hopefully things can pick up

 

[Amanitas]

Is it a CA emissions car?

A CA emissions car will have a trap oxidizer in the exhaust which can cause issues...however, the good news is, it's still covered under a recall, and if they find that the trap oxidizer caused damage to your turbo, they'll replace the turbo for you

I don't think it is. I mean, I'm not in California? If that's what you mean? And, it has never been there... so... I don't know. How do I determine this specifically?

Coolant: Open... squeeze, plug, release... repeat as necessary. Got it. Sounds like fun on a Friday night!

If I remember correctly, the front end is pretty tight. I drove her for a few weeks before selling her before, and I don't think the guys did anything heavy to her since then, but it won't hurt to check.

I remembered one more thing: the top of the engine has some kind of vacuum operated linkage thing which supposedly does something I can't remember, but in this car it's removed anyway. It seems as if it was supposed to be there, but the previous owner eliminated it, just left the mounting brackets and some misc. things. I should get the book and figure out what it's called... instead of "that guy in that movie about that thing at the place over by that huge lake? You know?"

Ok, thanks!

 

[The Warden]

I don't think it is. I mean, I'm not in California? If that's what you mean? And, it has never been there... so... I don't know. How do I determine this specifically?

Coolant: Open... squeeze, plug, release... repeat as necessary. Got it. Sounds like fun on a Friday night!

If I remember correctly, the front end is pretty tight. I drove her for a few weeks before selling her before, and I don't think the guys did anything heavy to her since then, but it won't hurt to check.

I remembered one more thing: the top of the engine has some kind of vacuum operated linkage thing which supposedly does something I can't remember, but in this car it's removed anyway. It seems as if it was supposed to be there, but the previous owner eliminated it, just left the mounting brackets and some misc. things. I should get the book and figure out what it's called... instead of "that guy in that movie about that thing at the place over by that huge lake? You know?"

Ok, thanks!

Sorry for the delay in responding...

If the car's never been in CA, then it should be a federal-emissions car....but, CA emissions cars have popped up all over the place. The simplest way to tell is the air cleaner...if it's directly over the turbo, it's a federal car; if it's right behind the right headlight in front of the coolant reservoir, it's a CA car.

Do you have any pics of the engine? There's a vacuum device on top of the valve cover on many cars, but it was eliminated in '85. The device controlled the EGR valve and IIRC the tranny shift points based on throttle position...my overly-medicated mind's drawing a blank on exactly how, but these were controlled by different means on '85 cars. The pic I'm attaching shows what the valve cover looked like on a stock '85 (federal emissions) car.

Hope this helps a bit...good luck!