Hello friends,

As many of you know, the gearing on a 240D with a 4-spd stick causes the engine RPMs to kinda soar at today's highway speeds of 65+ mph.

My trusty 240D has 283K miles, has been with me through 80K of them, and has had a front main leak that mostly only rears its head when driving over about 67 mph. I have been hypothesizing that the crankcase pressure got high enough at those RPMs to make weak old seals start to lose strength. This is not a smokey engine and has always been a strong starter even below zero. No noticeable smoke at startup or idle, and just the "normal" amount in people's headlights through the rearview at night. Oil pressure good and never overheating. Bosio injectors with 15K mi on them. Oil usage is not terrible like some other posts but generally occurs only when driving over that 67 mph trigger, at which I thought all the oil loss was leaked. The car does leave behind a little breadcrumb trail of oil drips after a highway drive. Never a WVO car or anything like that. 15W-50 in summer, Mobil1 10W-30 in winter (per service manual viscosities over varying temps).

Last night I was taking the car down to a detailer's with my girlfriend following, and she called me to say that there was a notable amount of white-ish smoke pouring out the tailpipe as soon as the car hit 65 mph. We switched cars and sure enough, intermittent "puffs" of white-blue smoke as soon as we hit 65. Not a constant stream, mind you, and I could smell "diesel engine" as I followed.

So my problem is more simply phrased: My car notably leaks oil and seems to burn oil but only when driven at high RPMs.

All that brings me to my questions. I've read about sticky oil rings, bad compression rings, and lots of other issues before posting this new thread. Does my problem sound like one of these kinds of rings? Is there any breather that should be venting the crank pressure that could be clogged? (There is oily crank pressure coming out from the oil spin-down back into the intake manifold, so that's not plugged but might be restricted.) Any other thoughts? Do I need a rebuild? I have taken such good care of this engine, never put a load on it before it warmed up, and was under the impression I should get at least 300K miles before needing a rebuild.

Sorry for the verbosity but I wanted you all to get a handle on many of the details without having to ask later.

Thanks guys for your time and thought.

Garrison

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Garrison R.
'83 300D

I tend to think it is a belief that at speed the 616 does consume more oil than normal. Or more accuratly a lot of them do. It is the lowest geared of all the 123 diesel models remember. So revs are obviously a lot higher.

To what extent base oil consumption is probably determined by factors like the general engine wear. Anyways I feel that any 616 that consumes less than one quart of oil every 1200 highway miles is pretty good. Your front seal may just be a little tired rather than it's effectiveness ruined by more blowby pressure. The blowby canot be too strong or it would shut the injection pump down. You want to make sure the vent system for the crankcase is nice and clean from end to end. If too much blowby the air filter would be well oiled as well remember unless the oil separater was really good if you have one.

First of all I would try to get some indication of oil consumption at highway speeds. Although it is difficult to factor in the leak at the front seal.

I cannot comment on the tailpipe emission observed. If visual it takes quite an oil consumption rate to show. It may or may not be directly oil related. Hopefully someone else has better suggestions. I do own a couple of 240ds.

Still your question left me a little adrift. Kind of sounds like if your coolant level is not dropping. There is not much to be done other than checking the injection pump timing, the Injectors general condition, and slapping a new front crank seal in. May as well set the valves at the same time so you have done a pretty comprehensive tune up. Although the valve clearances should have very little to do with your issue. Better safe than sorry.

The intermittent nature of the white puffs seem to indicate it may not be base oil related. I suspect that burning up at excessive rates would be more constant in nature. Also your consumption would be less than three hundred miles perhaps even less than that.

The only base oil related intermittent thing might be an intermittent leaking head gasket perhaps. You have a bit of work to do before even considering that avenue in my opinion. It also is far from common on these engines.

If my memory serves me correctly, some valve covers have more elaborate baffles in them to stop engine oil from mixing with the crankcase gases as they are collected. I'd conduct an experiment. Temporarily remove the PCV hose and replace it with a longer one that vents into a clear gallon jug (with a hole in the top for the gases to escape. See how much oil accumulates as you drive around town for a few days. Then empty the bottle and drive at 67+mph for a while and see how much oil accumulates in the jug. I'm guessing a substantially greater amount. If I am correct, you could then fashion your own oil separator using the jug to collect the oil and a second hose going over to the air cleaner to introduce the gases back into the manifold. Then, once in a while, pour the oil back into the engine.
ForcedInduction had a picture of his system posted on here at one time. I'm guessing it is now gone.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Marvel MM oil results sticky rings
Origional thread also has + response
Compression Test...how low is low.....

Other thoughts;
There was a recent Thread concerning Oil in the Air filter fromt he Blow By. The symptom was White Smoke.
Other reading say white smoke is caused by unburned Fuel (Oil ?) or Coolant. And, I have seen on one of my own Diesel Vehicles late timing cause large volumes of white smoke.

Worn Valve Guides/Sems and worn Valve Guide seals can allow Oil to run down the between the Valve Sem and Guide and into the Cylinder during intake.
I would guess Crankcase Pressure would aid in the above.

Worn Exhaust Valve Guides/Stems and seals can allow Exhaust Gas by them and also increase the Crankcase Pressure.
(My Father had a gas Car that had worn Valve Stems/Guides; if the Crankcase Breather was on the Engine the Crancase pressure was high enough it puseh Oil out frombetween the Oil Pan Gasket. No Oil leak with the Crankcase Breather removed.)

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84 300D, 82 Volvo 244Gl Diesel

Thanks for the thoughts - I did have to adjust the IP when I replaced its leaking gasket 25K mi ago. Timed it with drip method and the performance has been pretty good but I felt like before I did that work it might have been peppier. By now I'm used to it.
IP timing sounds like a recurring theme here and I should probably recheck the timing and/or advance it a hair.

I love the idea of testing the amount of oil coming out in a separate jug, and also cleaning the entire venting assembly.

I planned to do a valve adjustment this coming weekend; perhaps that will help too.

Nobody is yet saying, "Man, those cylinders are shot and you need a new block." I'm (obviously) glad about that!

I'll report back with findings and photos if appropriate.

Thanks again! You all are amazing.

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Garrison R.
'83 300D

If you put one of those waste-O-money K&N air filters on your car, that can add lots of force to your blow-by stream and really make the cap dance. At least, it did on mine. When I bought it, the cap sat on there like the Queen Mary under sail. A few weeks later, I could hardly keep it on the head. I panicked pretty bad and posted "help, I've ruined my engine" threads everywhere I could, but it turns out it's just because there's less vacuum because the air filter draws more easily. Just a thought ...

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Finn John -- Albany, Ore.
www.offbeatoregon.com
76 Merc 300D, sky-blue, *86k, for driving
84 Jaguar XJ6, black, 245k, for restoring someday
71 Merc 408, 2.3 petrol 4, Avon caravan conversion (UK), RHD

This gentleman reminded me of the oil cap test. Try seeing if the cap just dances a little or is blown right off the valve pan.

A little dancing is probably an indication of acceptable blowby at idle. Blowing into low orbit at idle is another matter. Again make sure the normal vent system is clear before doing the test.

I was searching for the bag of blow by and came across this one.

How to Measure Blowby

Not the one I was looking for, but interesting and give you a good laugh.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works