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The220D 07-30-2008 11:43 AM

HELP NEEDED - Smoking like crazy, shaking, and more. Is this the end?
I've been slowly bringing a 1970 220D back to life for the last year or so. New hoses, new rear brakes, new battery, and more. Changed the glow plugs and both fuel filters this past weekend when she wouldn't start on Thursday.

After replacing the glow plugs and changing both fuel filters, the car was running beautifully. Drove it to work Monday without incident, and then again on Tuesday. It ran better than it has since I rescued it a year ago.

Ran an errand Tuesday afternoon and filled it up at the Exxon station. Added some Diesel Kleen to the tank too. Drove home that evening. Went out about an hour after I got home to drive downtown to a social event. Car started fine, but it began smoking within 5 minutes of my starting the trip downtown. The brakes also felt strange – like the power brakes weren’t working or something. About 5-10 minutes into the trip I stopped at an intersection. The car began running very rough, idling higher than usual, with a ton of gray smoke billowing out. I turned the car off and checked under the engine. Couldn’t spot anything amiss. Checked the oil – level was fine. Started her up again and drove the rest of the way downtown. She smoked the whole way (not as profusely as when I had to stop, but much worse than it ever has).

Started her up again this morning. Brakes still feel like they are working, but without the power brake system kicking in. Very hard brake pedal, etc. I’m at a total loss as to what’s going on with this.

Drove her about 10 minutes when she suddenly started billowing gray smoke again. It totally engulfed the car. High, rough idle, car shaking, sounded like it was knocking/pinging. I tried to shut the car off by pushing in the starter nob and taking the key out, but it literally did not turn off. I pulled the nob back out maybe 10 seconds later when the light turned green and drove off. Much less smoking and it runs smoother once I get it into 3rd gear and up to 30 miles an hour or so. Brakes still not right either.

What the heck is going on? Is this just a tank of bad gas (diesel) screwing up my engine, or is the problem much more serious?

bgkast 07-30-2008 12:00 PM

It sounds like it is the end......of your vacuum pump.

When it begins leaking it will pump oil vapor into the intake manifold which would cause the car to smoke and run roughly, and make your brakes not work. Try hooking up a vacuum gauge to the main line coming off the pump. You should get in excess of 20" (I think, can somebody confirm this).

Re-build the pump before you drive it any more. I have heard of them dumping their guts into the timing chain, which will totally ruin your day.

DieselClack 07-30-2008 12:17 PM

Yep, Your vacuum pump is on it's way out and I would not even run the engine anymore until you either rebuild it or replace it! These things have been known to puke their parts into your motor and this would be the end of your motor!:eek: The timing chain will break when pieces of metal are tossed into it and your pistons will hit the valves in the head while your motor is turning, a really expensive fix if your head is not totally destroyed!:eek:

Your vacuum pump is dumping oil into the intake and since this wasn't designed to burn, your smoking like a coal train!:D Fix this now, today or ASAP without running the car or it's off to Mercedes Benz heaven unless you have a lot of money!!!!:eek:;)

nhdoc 07-30-2008 12:35 PM


The220D 07-30-2008 02:19 PM

Thanks for the diagnosis advice. Just checked the price of a new one - $650! Ouch.

bgkast suggested that I rebuild it. Is that doable by a newby? I also saw repait kits sold on fastlane. Should I try one of those, or just replace the sucker?

nhdoc 07-30-2008 02:24 PM

It can be rebuilt using the rebuild kits. Before you commit to anything confirm it is the should be able to see oil in the line which goes from the vacuum pump to the intake manifold. Disconnect it and inspect it. If so then you have a tear in the diaphram and need to rebuild it. 99% sure this is your problem but it is always best to confirm before ordering parts.

The220D 07-30-2008 05:36 PM

I'll check the line to make sure. If it is the vacuum pump, do I need an assembly plate if I want to try to repair the pump myself? See:

nhdoc 07-30-2008 05:49 PM

The manual you cite is for the W123 chassis...I think the earlier pumps are different. I can't find any mention of them however in my shop manual for the OM616 or W115 chassis. Others who have experience with both might chime in? I remember reading the diaphram can be replaced without removing the pump from the car.

DieselClack 07-30-2008 06:49 PM

Remove the vacuum pump completely and inspect it. You cannot always find how badly it is worn out without looking at the roller bearing where it contacts the pump plate!;)

Try https://www.***************/index.html This site is one of the best for replacement parts and one of the lowest priced if you can't find your parts here.

Here is a good price on the entire pump if you want to do your repair this way. I bought a vacuum pump from here and then rebuilt my old one when I had time so I have a replacement ready to go! (I have 7 Mercedes Benz's!:D)https://www.***************/search/product.aspx?sid=34kzmm45lt1ccdqqcaudfoep&makeid=800016@Mercedes&modelid=1192812@220D&year=1970&cid= 18@Electrical%20%26%20Vacuum&gid=5172@Vacuum%20Pump

kerry 07-30-2008 06:53 PM

Diaphragm can be replaced with most of the pump on the block if your pump is similar to the one on the early 617na engines. It's a one hour job.

The220D 07-30-2008 10:35 PM


Originally Posted by nhdoc (Post 1925629)
The manual you cite is for the W123 chassis...I think the earlier pumps are different. I can't find any mention of them however in my shop manual for the OM616 or W115 chassis. Others who have experience with both might chime in? I remember reading the diaphram can be replaced without removing the pump from the car.

You're right - thanks for pointing out that I was relying on a manual for a totally different car! Ack. My brain is fried.

Can't seem to find an online manual for the 115, so I may have to give it a go w/o any directions. Probably not a great idea, but my options are limited.

arkie 07-30-2008 11:06 PM

The higher idle and smoke is because it is pulling oil out of the engine and using it for fuel! You are at risk of a runaway diesel - I wouldn't even start it up again until you have fixed the pump.

Lycoming-8 07-31-2008 12:19 AM

Did this repair job on the old '68 many years ago. Seems like the instructions that came with the repair kit were quite helpful. Previous comments about the ease of the job are pretty much true. Seem to remember something about optimum positioning of the pump cycle can help with installation of the diaphram. Did mine wiht th emajority of the pump still attached to the block.

bgkast 07-31-2008 03:12 AM

Does the early vac pump have a vent line that runs to the air cleaner, or does it just vent into the crank case?

The220D 07-31-2008 05:19 PM

1970 220D vacuum pump repair advice needed
It vents into the crank case (as best I can tell).

I disconnected the line (clearish plastic) going from the vacuum pump up to the crank case. It was coated with oil inside. Didn't pour out or anything, but it dripped out and I had to clean the threads of the connections which were coated with oil.

Based on the responses to my post, it sounds like the vacuum pump needs to be repaired. I plan on ordering the repair kit (diaphram, etc.) and working on it this weekend.

My concern is whether I'll be able to pulll the top 1/2 of the vacuum pump off to work on it. The pump is mounted on the front of the engine, below the fuel filter, with the radiator and fan directly in front of it. I think I can get in there with a long handle wratchet & use that to remove the screws, but how hard is it going to be to line the top of the pump up correctly when I'm reinstalling it, etc.?

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