82 240D lots of oil at breather tube - PeachParts Mercedes-Benz Forum

briandownunda · #1 10-02-2008, 06:34 AM

Hi,

I just purchased a very nice 1982 240D with 160k orig. well documented/maintained miles from the original owner. The owner told me that a few months ago the vehicle started using huge amounts of oil (around 1 quart every 100 miles) and started idling very roughly all at the same time.

I see that quite a bit of oil is coming out of the breather tube at the valve cover.....any ideas on what might be causing that ?

The car seems to run fine at higher RPMs ~1300 and up, but at lower RPMs runs very roughly and will stall if I don't feather the accelerator. The car also seems to startup up just fine, so long as I play with the accelerator.

It seems strange to me that the high oil consumption started all of the sudden, I would think that a worn out engine would gradually consume more and more oil. Any ideas or suggestions would be really appreciated. BTW I recently purchased a diesel compression tester and plan to give the old lady a test soon.

Thanks in advance,

Brian

rs899 · #2 10-02-2008, 06:54 AM

Broken ring? Doesn't sound good. You might be able to pull the prechambers and see what is going on but that's a lot of oil to use so suddenly.

You can check compression - that might give you a clue, but may not be conclusive by itself.

#3 10-02-2008, 06:55 AM

Check for oil in the exhaust. You can also remove the exhaust manifold and look for wet exhaust ports, that will tell you which cylinder is burning the oil.

briandownunda · #4 10-02-2008, 03:03 PM

I hope this isn't broken rings :-(...hopefully the compression test will get me closer figuring this out.

Is there a way to tell if there is oil in the exhaust w/o removing the exhaust manifold ?

Thanks,

Brian

Diesel911 · #5 10-02-2008, 04:16 PM

Before you do a compression test you might want to adjust the valves so you know the valves are closing completely and when they are supposed to.
While the Valve Cover is off look over the valve train and see if anything is not normal.
Also check the Camshaft Timing which can also give you some idea of what is going on with the timing chain.
In the left of this split pic is the Camshaft Drive Gear aligned to the Camshaft Bearing tower. On the right is A pic of my Crankshaft Damper degree marks. In my case showing my Camshaft Timing is about 2 degrees late (past Top Dead Center); indicating normal wear/stretch on my Timing Chain and Timing Chain drive and that I have not jumped a tooth.

kerry · #6 10-02-2008, 04:57 PM

If this engine has an early model vacuum pump, it could also be sucking oil into the intake via a ruptured vacuum pump diaphragm. This could be detected by removing the vent line which goes to the aircleaner while the engine is running to see if oil is passing thru it.

briandownunda · #7 10-03-2008, 06:16 AM

How would I know whether oil passing thru the breather tube is from blow by or from the vaccum pump ? Does anyone know if the 1982 240D has the old style vacuum pump ? Is there a way to identify which pump I have &, if so, whether it is leaking ?

Based on the history of the car (I have every receipt for the meticulous servicing the car has had), I am wondering if a broken ring is a probable issue at 160k ?

One more thing, I know there is a problem with the right rear door lock and truck lock vacuum as neither work.....the others seem to work on the up swing but not on the down swing I think.

Thanks,

Brian

rs899 · #8 10-03-2008, 08:44 AM

You have the new pump. I have never heard of those failing at such low mileages, nor are there any reports of bad rings. But stuff happens.....

briandownunda · #9 10-06-2008, 06:49 AM

Can someone tell me how to tell if my vacuum pump is bad ? 3 of my door locks will go down when I push the driver's side lock down (the right rear and trunk do not), however, none of the locks come back up when I pull up on the drivers side lock. Not sure if that is any indication of a pump failure.

If lots of oil is coming thru the exhaust, should I see oil dripping out of the tail pipe ?

One more thing, from a previous post, I am told that I have the "new vacuum pump". If that pump fails, will it cause excessive oil consumption or does this only happen with the old pump ?

Thanks !

Brian

coonerboy · #10 10-06-2008, 07:41 AM

Disconnect the large vacuum line going from the pump to the brake booster. If you have oil in this line I would suspect your vacuum pump is bad. You could also check the amount of vacuum you are getting with a vacuum gauge.

Is there smoke coming from the tailpipe when its running. There are only 2 choices here. Its either burning the oil or its leaking it.

dieselnutnj · #11 10-07-2008, 07:44 AM

a quick check to see if your problem is excessive blowby is to loosen the oil cap on the valve cover while the engine is running. IF you have a ring issue which I highly doubt the cap will blow off, if it just bobbles around then you need to look elsewhere. The newer style pump does not "vent" into the intake system like the older one. Carefully check all the parts in the PCV system on the engine. I'll look later on my spare engine and let you know what to look for.

briandownunda · #12 10-07-2008, 11:12 AM

I did the cap check & the ring blew right off :-( Does that mean for certain that I have ring problems ? If so, is it possible that one or more are stuck ?

I still plan to do the compression check when time permits.

Thanks,

Brian

Bajaman · #13 10-07-2008, 12:23 PM

Certainly doesn't sound good. The compression test or better yet a leak down test will tell you if the rings are shot for sure. That much blowby will certainly carry oil with it into the intake.

moon161 · #14 10-07-2008, 01:12 PM

There should be a cyclone air-oil separator at the front of the air cleaner. If there is, make sure it's not plugged, and drains properly. It's fed by the breather, exhausts to the manifold, drains to the crankcase. If by chance compression is gone and you junk the engine, lemme know, I'll buy the separator.

briandownunda · #15 10-07-2008, 02:59 PM

could that "cyclone air separator" being clogged up cause the oil filler cap to do that as well, or can only blow-by do that ?