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Car Forum / Mercedes-Benz Cars / September 2005New/Used 190D
I don't know the history of the car, I just got it and got it started. Had some gray smoke at start-up, then less as I revved to warm up, and blow the gunk out a little bit. As soon as it would idle without the pedal, I looked around the car an saw a lot of oil coming from the exaust. I shut the car off, and checked to see that the oil was from the crankcase, and nothing else. The oil had dropped at least a quart, and all the other fluids are unchanged. There is no mixing of fluids, no loss of coolant, and the engine was running smooth and started easily; especially for a car that sat for a few years. The car is a 190D, with hydraulic lifters, and no turbo. Does anyone have an answer? Thanks, Jay Your post states the engine was run only briefly, the car not driven, yet the engine's oil level fell 1 quart and oil dripped from the exhaust. Best case is that the oil in the exhaust line is old fuel from the engine's often being cranked - perhaps for long periods - idled and shut down. That may be true IF the dripped oil is thin, like diesel fuel, and not slippery. A possibility that I urge you to check is a clogged engine air filter. The crankcase or valve cover "breather" (which disposes of "blow-by" from the cylinders) is connected to the engine's air intake (to burn these fumes). Sometimes this oily air gets onto the paper air filter element and soaks it and so clogs the air intake choking the engine for air. I suggest you check the intake airway to the engine as the first investagory step. Worst case is worn out piston rings or a broken piston ring; either would throw lube oil into the cylinder(s) and so into the exhaust and that oil would be slippery. The only way to know for sure is to have an independent M-B shop perform a compression test. Pick carefully for this shop may be the one to fix or replace the engine if the diagnosis is bad. Conversely, one could just drive it a bit to see what happens - bring your phone and AAA card. Suggest you call Performance Products 800-243-1220 for free parts catalog #45M which covers this model. Includes exploded parts diagram of engine. An additional thought: If the engine starts and runs smoothly BUT pumps lube oil into the exhaust I'd suggest a loose valve guide is to blame. The valve guide is the sleeve in which the valves pulsate; it should be tight in the cylinderhead but if it has come loose and is floating oil can be sucked around it into one cylinder in the quantity that you describe. All this is just under the valve cover and, while not minor, is not a huge repair. If that is, in fact, the problem the timing chain ought to be replaced while its a part given the mileage on the engine. > An additional thought: If the engine starts and runs smoothly BUT pumps > lube oil into the exhaust I'd suggest a loose valve guide is to blame. [quoted text clipped - 4 lines] > is not a huge repair. If that is, in fact, the problem the timing chain > ought to be replaced while its a part given the mileage on the engine. I agree although it seems to me that if all that oil was going through a cylinder that is firing (so to speak) they you would expect to see quite a bit of blue smoke also? Just a thought Marty Sir, Thank you for the excellent answers! I knew I could count on you; as I've read through nearly all your posts to this forum, and gleaned quite a lot of useful information for my efforts. As for "best case" scenario, I'm not holding much hope, as I've pulled the breather from the valve cover and it's clear. The air cleaner element is relatively clean also (not wet with any fluid). There is about 1/2 teaspoon of fuel (fuel smell, but mostly darkened, as if mixed with oil; or maybe just the condition of the intake's internals) in the air cleaner housing. (which may be indicative of something?) I'll remove or replace the element before another try at starting. As for the breather; I've only pulled the hose that connects directly to the valve cover... none of the hoses that this one connects to were removed, yet. Is there a pcv valve? This one's just a hollow tube with an elbow into the valve cover. As for "worst case", the oil from the tailpipe was slppery. No real fuel odor discernable. So, if I find a broken ring or an out of round cylinder, are there over-size pistons available if needed? Can the block be machined to make these repairs? I called Performance Products for their catalog, thank you! The diagrams will really come in handy... but hopefully not TOO many parts! (but it's nice to have a good source) I'm hoping that it's the valve guide. It seems from other posts that this is a "common" cause of like symptoms. One other thing I'm considering is the oil drain-back "tubes"... the oil was very dirty, do you think these tubes may be clogged, causing oil to be re-routed? Or would this cause a no-running condition, or much more smoke than I reported? The smoke (or mostly lack of smoke), as noted in Martin Joseph's reply, is really confusing me... if the oil had come through the combustion chamber, why not huge amounts of blue smoke? I'm just guessing that the valve with the loose guide is allowing a straight through pass of the engine, would this make sense? If it were a loose guide, would it drop parts and pieces into the cylinder? Well, Thanks Again! Jay > One other thing I'm > considering is the oil drain-back "tubes"... the oil was very dirty, do > you think these tubes may be clogged, causing oil to be re-routed? No, that wouldn't be it. With regard to the smoke thing, it's a diesel, so I really have no personal experience. It seems like figuring out how to compression test the engine, and then doing a wet test (adding oil directly into cylinders), might definitively rule in or out the valve guide issue. Even if the car has valve guide/seal issues, you might not want to spend a bunch of time and money fixing these until you are certain the bottom half is solid... Marty Jay, You have the M-B bug! Diesels have no PCV valve. The lube oil in a diesel is typically black (soot in suspension), soon after an oil change. Black is OK - normal. But know that a diesel requires diesel grade lube oil that's designed to carry that soot in suspension. Doubtful that cam box's oil drains to crankcase are clogged. A loose exhaust valve guide would dump oil directly into the exhaust manifold. When the engine is run long enough to get hot that oil will begin to smoke and the car will lay down a real smokescreen! There won't be any significant broken pieces from a valve guide - perhaps a few crumbs of metal but no chunks. So, what to do next: Remove the valve cover or take it to a shop. The cover can always be replaced after a look about - so what if it leaks a bit until the engine is fixed. So the question is who will fix it if, in fact, it's a bad valve guide. The valve guide is supposed to be solid in the cylinder head; this one is suspected of being at least loose in its socket or (worse) its socket (now) being worn. The extent won't be known until its carefully examined. Realistically the cylinderhead ought to be removed, but if not too bad, an experienced shop may be able to fix it without removing the head - buy those guys a case of something good! The exploded parts diagram shows this to be a beautifully simple engine. It has cylinder liners (steel sleeves that are fitted into the block that can be replaced when worn so the cylinders aren't bored out). One can buy almost everything as a part except the block! You'll have fun with the parts diagram. Let us know how its going. Tom |
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