1982 240D Oil consumption concern. - PeachParts Mercedes-Benz Forum

yoog · #1 01-14-2011, 04:11 PM

I have 1982 240D automatic. Recently got used engine(~160K miles) installed by a Mercedez only mechanic. The problem this replaced engine has is burning oil. If I drive in town (below 50 miles) it burns around a quat per 350 to 400 miles. When I drive on highway above 60mph, it burns like 2 qut per 60 miles or so. The mechanic changed oil recovery unit (sponge like part) but same result. Now he says that you might have to replace oil rings on piston, a major work. If this was the case then it should burn oil at all the time and not only at highr speed. Also driving on highway, car does not emit black smoke indicating highr oil consumption.

I am baffled. What is wrong with this replaced engine?

leathermang · #2 01-14-2011, 04:18 PM

First be sure you are not starting with the oil level above half way between the high and low marks.
Second be sure you have the correct color oil dip stick for your car.... that probably ought to be number one..
Check to correct any leaks it has... a new copper crush washer on the oil pan drain plug is a good place to start... and clean the engine.... and start putting used paper under the car to spot any leaks..
Be sure your valves are set correctly also.

Replacing oil rings is major major work...
did you have any claims by who you bought the engine from as to ' usability ' ?

What is an 'oil recovery unit ' ?

Does your engine smoke on ' start up' after sitting ? If so , you may get lots of improvement with simple and cheap valve stem seal replacement.

kerry · #3 01-14-2011, 04:31 PM

Black smoke is not an indication of oil being burned. Black smoke is unburned diesel fuel. Blue smoke or white smoke is oil burning.
Check your blowby. With the engine warm and idling, removing the oil fill cap and see how much pressure is being expelled. Take a video of it, post it on YouTube and put the link here where people can see it.
Consumption under the conditions you describe is often oil getting pushed from the crankcase to the intake manifold as a result of excessive blowby. If the engine that was put in your car sat for a long time, the problem may be resolvable without a rebuild.

thatguy · #4 01-14-2011, 05:38 PM

It may help your car a lot to replace the valve stem seals. If those start to go, your car can begin consuming some oil.

leathermang · #5 01-14-2011, 05:42 PM

Quote:

Originally Posted by thatguy

It may help your car a lot to replace the valve stem seals. If those start to go, your car can begin consuming some oil.

Good suggestion !!!

thatguy · #6 01-14-2011, 05:58 PM

Quote:

Originally Posted by leathermang

Good suggestion !!!

Ah I didn't see your post. I clicked "reply" and walked away from my computer for a while then came back and typed the same thing. Hey, it's such a good suggestion it's worth mentioning twice!

pawoSD · #7 01-14-2011, 06:01 PM

2qt per 60 miles would cause a steady stream of smoke, as at that rate....over 1/4 of the "Fuel" to the engine is oil!

I'd be checking for leaks, verifying proper oil level and proper dipstick as was mentioned above. Idling with consumption like that would emit a very foul exhaust and smoke, you'd be able to smell the oil burning.

leathermang · #8 01-14-2011, 06:30 PM

Thatguy... I really think it is a good suggestion.. cheap and seldom addressed even on 300 k mile plus engines...

pawoSD · #9 01-14-2011, 06:39 PM

Quote:

Originally Posted by leathermang

Thatguy... I really think it is a good suggestion.. cheap and seldom addressed even on 300 k mile plus engines...

Two of our 617's have between 307k and 315k on them and use no oil between 5k changes. The other engines have 170k and 235k....neither of them use any either.....

An engine burning that much has something very bad going on, not too likely that its valve stem seals. When those were in super bad shape on my gasser it only used about 1qt per 750 miles....and on a diesel there is no vacuum, so less gets drawn in in the first place.

2 qt per 60 miles (if accurate) is extremely severe.

If the engine really only has 160k on it, it was either heavily abused, or something else is wrong.

leathermang · #10 01-14-2011, 06:45 PM

Quote:

Originally Posted by pawoSD

...and on a diesel there is no vacuum, so less gets drawn in in the first place.

There is vacuum in a diesel.. just not the kind found in a gasser which can be used to run the brake booster, etc..

Anytime there is moving air... there is likely to be a low pressure draw from neighboring areas... and worn valve stem seals can let a lot of oil past the valve stems when worn... even though the typical first indicator is that upon sitting for a while there is noticeable smoke upon startup....

It is a little labor.. but one a careful DIY person can do..and they are cheap.. I think about $20 for the whole set... of course, if I went that deep I would put in new springs also ( cheap too )...

Diesel911 · #11 01-15-2011, 01:31 AM

Something Cheap and easy to try if you believe the rings might be sticky:
Marvel Mystery oil results sticky rings
Original thread also has + response
http://www.peachparts.com/shopforum/showthread.php?t=258757&highlight=Marvel

If the Oil was actually burning well inside of the Engine I might not smoke as much as you might think; because since the Oil has become Fuel you simply would not be giving it as much Pedal to go the same speed.

I would be curious and pull one or more of the Glow Plugs to see what type of Carbon build up is on them. If it has a shiny build up I would suspect Oil burning.

I believe it is 2 members who said that the little O-ring in the Fuel Supply/Lift Pump was bad and it caused Oil to be sucked into the Fuel Supply/Lift Pump and mix with the Fuel. I believe one of them said his Fuel had a pale Grayish color to it due to the black Oil mixing with the Fuel.

There has been more than one member who has said that replacing the Valve Stem Seals reduced the Oil Consumption.

It is common for an Engine to use more Oil when it is run at high speeds; but not the amounts listed by the OP.

Diesel911 · #12 01-15-2011, 01:53 AM

This is all I could find:
83 300 D oil in diesel fuel
http://www.peachparts.com/shopforum/showthread.php?t=261822

If Engine Oil did mix with the Fuel inside of the Fuel Supply/Lift Pump when it goes through the Injector it would get atomize and burn just like the Diesel Fuel; I believe without any abnormal smoke and most likely no abnormal Carbon deposits.

See post #12 for a pic of the O-ring and Lift Pump.
http://www.peachparts.com/shopforum/showthread.php?t=291498

yoog · #13 01-15-2011, 05:05 PM

Quote:

Originally Posted by kerry

Black smoke is not an indication of oil being burned. Black smoke is unburned diesel fuel. Blue smoke or white smoke is oil burning.
Check your blowby. With the engine warm and idling, removing the oil fill cap and see how much pressure is being expelled. Take a video of it, post it on YouTube and put the link here where people can see it.
Consumption under the conditions you describe is often oil getting pushed from the crankcase to the intake manifold as a result of excessive blowby. If the engine that was put in your car sat for a long time, the problem may be resolvable without a rebuild.

Thanks for the quick reply. I am completely lost as to what is blowby as I know nothing about diesel (newbie). Hence, I will ask few people and then try to post the video.

As far as smoke color goes, when I start the engine in the morning, a little black smoke comes out and after that no BLUE or white smoke.
I am totally confused why oil consumption is very low when I drive in-town below 50mph. It engine burns oil, it should burn no matter at what speed.
Moreover, ther is no leak otherwise, not on the floor onr on the engine.

kerry · #14 01-15-2011, 05:20 PM

Blowby refers to gasses that pass by the piston on the compression and power strokes and enter the crankcase. These gases build pressure in the crankcase and need to escape. The hose from the valve cover to the air filter (pcv=positive crankcase ventilation) allows these gases to escape. Very high pressures will cause oil to escape along with the gases. With the oil fill cap removed and the engine running it is easy to get a sense of how much blowby an engine has.
Gasoline engines have blowby also but since diesels run on higher compression, there tends to be more blowby in a diesel engine.

yoog · #15 01-15-2011, 07:50 PM

Quote:

Originally Posted by kerry

Blowby refers to gasses that pass by the piston on the compression and power strokes and enter the crankcase. These gases build pressure in the crankcase and need to escape. The hose from the valve cover to the air filter (pcv=positive crankcase ventilation) allows these gases to escape. Very high pressures will cause oil to escape along with the gases. With the oil fill cap removed and the engine running it is easy to get a sense of how much blowby an engine has.
Gasoline engines have blowby also but since diesels run on higher compression, there tends to be more blowby in a diesel engine.

Once again thanks for prompt reply.
I did a youtube search for blowby after I posted the previous post. I did check the blowby the same way the video did and in my opinion, there is not much gas coming out, atleast way less than the video had. As soon as I get a chance, I will shoot the video and upload to youtube, in a day or two, and post the link here.
Meanwhile I have attached the picture of what my mechanic refer as oil recover unit ( I don't remember exact wording he used).