Greetings all,

I am sharing some info as well as requesting some as well. I always felt I had a severe case of blowby because the air filter seemed to be saturated with oil. Through a little observation and common sense, I hope, I seemed to find leakage. I noticed after running the engine, on a 1980 300 TD station wagon for about five minutes or so that a thin line of oil or spit marks would appear in the vacuum tube coming from the pump. Upon removing the insert from the air filter housing I noticed that there was a steady oil dripping as well as only a oil fumes coming from the tube, and a lot less air pressure. Seems that some part of my pump has failed and has been sending oil to the air filter housing. Now for the question. I have an engine number 61791212059104 and I ordered a diaphragm repair kit from parts shop no. 0005864143 just wondering with all the choices they give if this is the correct repair part or is there something else that causes oil to bleed by the pump?


Thanks,

Charles

It sounds as if your common sense paid off. The diaphram kit should fix the problem.

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Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
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Charles, I rebuilt my vacuum pump and it is very easy, but one word of caution, you don't need a manual, but you have to make sure you slowly remove the covers from each end and make sure you take careful notes on the position of the diaphragms. If you don't have a manual and you have a diaphragm unexpectedly pop out when the cover comes off, you will have to ask for help regarding "up or down".

Greetings Super Turtle,

Your name of course seems to describe my car. Slow up hills and slow to accelerate. Hopefully I can find enough things to fix that will cure some of those problems. Hard to know what to expect out of it performance wise to judge if I am wasting my time or working in the right direction.

As far as the vacuum pump is concerned, don't know if your is the same or not but mine has a bell shaped housing screwed to the block, then on the end it has another smaller bell screwed to the first one, where it seems the diaphragm is located, I hope. After the first two bell housings that are screwed together there seems to be a rectangular plate on the end that is screwed to the smaller bell. Any idea whats behind it? Is it something else I should be replacing or is it a check valve of some sort?


Thanks,

Charles

Super Turtle is a nickname for an SD.

Well, you either have the single diaphragm, double diaphragm, or piston vacuum pump. Do you know which pump it is?

The repair kit for the single diaphragm pump which is the pump I think you are describing should have both a new diaphragm, and valves. I believe under the little rectangular plate you will find the valves under some springs, once again watch which way they are facing when you open up everything.

Then undo the smaller bell, and you should find the diaphragm.

Just matchmark all the stuff you take off, to reassemble it correctly.

The double diaphragm pump is the same except it has the same set up on both sides of the pump.

The hardest part was removing it from the engine, because I had trouble accessing some of the allen head bolts.


[Edited by '79 Super Turtle on 03-14-2001 at 11:33 PM]

Just following this discussion and have a question. My '85 300CD with 138k miles has a bit of oil in the air cleaner housing. Nothing on the element itself but a little bit around bottom where it sits and on the internal metal parts of the air cleaner housing.

My car starts great down to 17 degrees F (as cold as it got here this winter) and uses about one half quart per oil change. I use synthetic oil.

There is a bit of leakage at top of engine where rubber hose connects valve cover to air cleaner.

Anyone know what might cause this? I understand "blowby" is caused by worn rings but my compression seens good.

Thanks,

Nic in SC

In my opinion, your car sounds completely normal. I have yet to hear of a diesel that does not have a small amount of oil in the air cleaner.

Super Turtle,

Thanks, thats reassuring. I appreciate quality mechanical systems and try to stay ahead of problems.

Nic

Greetings Nic,

I thought all my oil in the air cleaner was coming from blowby as well, but couldn't quite believe that it would start up so easy and still leave oil in the air filter housing in qty. I simply pulled the vacuum pump fitting out of the filter housing lid and put one of my boys old white socks rubbered banded around the hose and plugged the lid hole I created and checked the white sock when I got to work. It was dripping with oil, so I knew then that my vacuum pump was pumping the oil out of the engine and into my filter housing. This is a technical procedure and requires special tools like the sock and rubber band. If you can't find them locally I can get them for you. If you just have a small amount of oil in the housing, as you say only using 1/2 a quart between oil changes, your engine must be new.


Charles

Greetings Super Turtle,

From the design alone it appears to be a single diaphragm pump unless there is a dual action that they have, but can't image how the air would leave the engine side of the diaphragm to do any good. Just looking at the housing it appears that the small bell contains the diaphragm and the rectangular cover on the end must cover up probably reed valves to control direction of air. Think that's right? Can't image having to replace them as well but for sure the leaking diaphragm.

Any other input? Do you have this in your manual? Hopefully my cd will arrive any day now and clear alot of what is left out of the Haynes, Chilton, and other Chilton manuals. Do these diesels seem slow to accelerate or is it just my imagination?

Charles

I just looked at my daughter's engine to verify, but the vac. pump on it has no connection with the air cleaner. It just draws vacuum on the brake booster and accessories. Yours must not be an '81.

Please report back with the results of this repair.

I have the double diaphragm pump, you cannot see the second rectangular plate which covers the second diaphragm and valves because it is opposite to the top cover. I believe you may have the double charles only because you say you have a line going to the air cleaner. I have a hard plastic line which I believe is a vent line going to the air cleaner, a hard line the same size (black)going to the brake booster, and a small gray line that feeds everything else which is pushed on with a piece of rubber tubing.
3 hoses total.


The single diaphragm is quite rounded and it only has two rigid elbow vacuum lines coming off of it. Both are the same size, and attached with nuts, there is no feed line to the air cleaner. 2 hoses total.

The piston vacuum pump has one hose.

All of these pumps were on W123's

What bother's me Charles is, have you checked the two vacuum lines for oil? It is possible you have a leak at the injection pump or transmission which is sucking oil into your vacuum pump.

Please check these hoses for oil and report back, it can spread very quickly through every vacuum hose, and you will have to replace many components.

Greetings All,

I only have two lines coming off the vacuum pump. One goes to the brake booster and the other to the air filter housing. The hoses are both swedge fitted to the pump, one black to the booster, one clear going to the filter housing. The clear one use to have quite a bit of air puffing out of it, that has now turned to a bluish puff of oily smelling air, and the volume has dropped. I would have to assume from that, the diaphragm has gone bad. the one going to the brake booster would be hard to get off as it is also swedge fitted to it's nipple. I guess it's possible to be sucking oil from the injection pump, but how could you tell for sure if either one could ingest oil into the vacuum system?

Charles

So it sounds like you must have the single for sure. Larry might have the piston vacuum pump with one line. Just pull off some of the vacuum hoses especially the one on top of the Injection pump going to the vacuum control module and see if you see any oil at all.

You can easily undo the brake vacuum line, and you will have to when you take your pump off anyway.

So is the diaphragm responsible for keeping oil out, or for creating vaccum in an oil free environment? Mine had a rip in it which resulted in a loss of vacuum, not oil in the pump. I belive the pump has a seal on it somewhere between the bearing that spins around and the flange it mounts to on the front of the engine.

Good Morning Guys,

You guys are way ahead of me here...but I infer from the discussion that there are variations re: tubes to air cleaner depending on engine type. My car ('85 CDT) has one black rubber hose going from top of valve cover to top of air cleaner. I don't think my vacuum pump is connected to the air cleaner.

What purpose does this hose serve? It seems to dump into a small canister within the air cleaner housing itself. None of the fittings are air tight.

My engine is original but always well taken care of and gently driven. I know from following various discussions that many (most?) diesels use a good bit of oil. My consumption is low by comparison and I assume that is not a bad thing.

Nic