I seem to be on a losing streak lately. I was adjusting my rack dampener in the driveway last night and listening to some other noises and so the car was idling for 15 minutes or so(I should add that this was after a 30 mile drive home from work, so the engine was already up to temp). The longer it idled the more smoke seemed to come from the exhaust and when I pressed the accelerator a pretty good amount of greyish-blue smoke came out. I took it for a little spin and came back and checked the oil and I was down at least a half-quart from before I started the idle! Prior to this I have used about a quart every 3K. The strange thing is, the smoke didn't really smell like burning oil. I let it sit for about 30 minutes and took it for a 6 mile ride (after adding oil) and everything seemed to be normal(I didn't let it idle first). Normally I have to let the car idle in the driveway in the morning for about 5 minutes or so (VERY steep driveway) to have enough power to get out and I notice a puff of smoke when I leave. No smoke any other time, so idling seems to be the big determining factor. Could bad turbo seals allow oil into the turbo at idle but not as much under load? In the last six months I have had new GP's, rebuilt injectors, valves adjusted, new tank screen and fuel lines and a lot more that isn't relevant to this problem. The car has 89,000 on the odometer (I bought it at 84K). Any ideas? '85 300SD. Thanks.

Just the opposite is the situation. Very little oil will reach the cylinders at idle due to the low airflow and low oil pressure. When the rpm's come up, the oil rushes to the intake manifold and the smoke will clear out the neighborhood.

Furthermore, you must be quite careful in making the determination that it "only smokes at idle". You can easily see the smoke at idle because the vehicle isn't moving. Once it starts moving through the air, the dispersion is significantly greater and your conclusion of reduced smoke might be false. It's necessary to clarify this point because all will be led astray with a wrong set of symptoms (very common on this forum).

I understand about the smoke dispersal when moving but if get home after a 30 min. drive and put it in park and lay on the accelerator for a second or two and let off I normally see very little smoke. In this particular instance, after idling for 15 minutes or so, I would see a lot of smoke after stepping on the accelerator in park. So I was curious if oil could get into the turbo while idling (little air flow) and then when winding up the RPM's the oil would be injected into the intake causing the smoke? Also, in this instance when I went for a drive after the idling, smoke was MUCH more apparent even with the dispersal.

How does the pressure in the intake manifold factor into this? At idle with the turbo turning very slowly, there would be little pressure in the manifold. Would this allow more oil to enter the manifold from a bad oil seal than at high rpm's when there's more pressure?
Half a quart low seems like a lot. Did you let the engine sit long enough for all the oil to drain back down to the pan?
I'd mimic the conditions a couple of times to see if it repeats.

__________________
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

I'm not really sure. I was just grasping at straws, trying to figure out how a long idle would cause a lot of smoke when running the engine. And the strange oil consumption. I may be projecting because I really want it to be the turbo and not rings! I did some searches, though and found some examples where sitting at a stop-light would create a lot of smoke at take-off and turbo-seals were suggested.

Here's where I got the idea:

http://www.peachparts.com/shopforum/showthread.php?t=234113&highlight=turbo+seals

On my 300SD, I used to get the big puff of smoke (lots of it) after idling at a stop light or stop and go traffic. This went away when I changed out my valve stem seals.

__________________
Joe

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1980 300SD - 495k miles - 'The Ambassador'
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Former Family Members
95 C280
73 280SEL
90 300D
87 300SDL (X2)
86 560SEL
84 300D
80 300SD

Ether, I read about your saga. How much oil were you burning? Is there any way to narrow it down a little more in terms of turbo vs. valve stem seals? I just can't figure out how the oil consumption could be so drastic for a short period of time and then sort itself out (I drove 30 miles to work today and checked the oil after the car had sat a few minutes and it didn't seem to be down noticeably)

My oil consumption wasn't horrible. Maybe a 1 to 1.5 quarts between oil changes. Since the seal replacement that seems to down by about half.

Prior to my seal change I had also rebuilt my turbo because it was squealing like a banshee. I didn't notice a significant change in oil consumption after the turbo rebuild.

__________________
Joe

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1980 300SD - 495k miles - 'The Ambassador'
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Former Family Members
95 C280
73 280SEL
90 300D
87 300SDL (X2)
86 560SEL
84 300D
80 300SD

This is a perfect example of the poor symptoms provided by an OP. In your original post, you mentioned nothing about very little smoke at idle. In fact, you stated that your problem is with smoke at idle.

Now, it's apparent that the smoke is not at idle. It's when you increase RPM's after sitting at idle for 15 minutes.

So, we now have a completely different conclusion. The new symptoms that you describe are perfectly associated with the problem of bad turbo seals.

I apologize if I wasn't clear. I did mention, though, that the longer it idled the more it seemed to smoke and then after idling for a while it would smoke very much on acceleration. To clarify: there is SOME smoke at idle and more the more it idles. When I press the accelerator after idling for a while there is a quite a bit of smoke. Normal driving conditions without lengthy idle=very little to no smoke. Is this still consistent with turbo seals? Thank you for your time.

How do you quantify "little or no smoke" when you are sitting in the driver's seat? Does your data come from the rear view mirror?

Yes, but I would add when I stop and put it i park, I give the engine a little rev and open the door and look at the tail-pipe. If I do that after a normal drive (no lengthy idle) I see no smoke either at idle or when I rev the engine. If I let it sit and idle for more than 5 minutes I will start to see wisps of blueish-grey smoke and puffs when I rev. Yesterday was an abnormally long idle (more than 15 min.) period because I was tweaking the idle-dampener and I saw much more smoke (big plumes when reving, steady wisps at idle) and noticed the oil loss(greater than 1/2 qt). Thanks again.

My conclusion is that the turbo leaks oil at all times. However, at idle, there is insufficient airflow to move the oil to the intake manifold and it pools at the turbo outlet. When airflow is increased, this large amount of oil will head toward the cylinders and generate the increased smoke.

If this conclusion is valid, the oil consumption is present at all times............not simply when sitting at idle. I question the validity of the data regarding the oil consumption.

Fair enough. I guess it's possible the seals have just gotten worse recently. Is there anything else that would exhibit these symptoms? Sticky ring(s)? Head gasket (not losing coolant)? valve stem seals? I'm planning on a compression check soon. I guess I would have to pull the turbo to find out for sure?