blow-by questions...
 

Are you supposed to 'hear' blow-by? When I took the oil filler cap off today, there was more smoke coming out there than at the exhaust and I heard a sound like a defective exhaust pipe, not very loud, though, but definately audible. How bad is that? Should I start looking for a new engine?
In addition: no start below 30, won't stay running after coldstart, once warmed up idle speed jumps up and down between 700 and 900 rpm but runs fine then.

The audible part is not a big deal. Pistons moving up and down, compression leaking into what is normally a closed volume, lots of air being displaced, you should hear a low frequency tied to engine speed. The rest of your questions demand more diagnosis. Many things contribute to poor starting, and nearly all of these cars with miles on them have blowby, yet they start and run fine. Do a search on poor cold starts and get a pot of coffee. You will find many, many posts to read. Most focus on glow plugs, starter performance, battery condition, and oil viscosity. An electric heater is an option, either the one MB supplies that fits into the water jacket on the block, or the ones that are in-line with one of the hoses. Some use a magnetically attached oil pan heater.

Good luck, Jim

Couldn't the sound like a defective exhaust pipe be a holed piston? I'd do a compression check if I were you. More smoke out the oil fill than the exhaust is not normal.

Thanks, Jim, I was just surprised because I never heard that sound before. With the other issues I've been playing around for a while already. Glow plugs are one year old and I recently tested their resistence with good results, battery is strong; I can repetedly glow and crank for quite a while. Starter seems fine, too, oil is Mobil 1 5W40. I have a block heater and it starts fine when it was plugged in, the problem is, I can't plug it in at work and I got stuck there twice already this winter.
At this point I suspect the IP, I will check the start of delivery next and if this doesn't solve it I will probably attempt a valve adjustment, although my mechanic says he did it when he put in the new timing chain 10000 miles ago. But you never know...
Any other ideas?
I was planning to test the compression also, although I'm quite sure that there isn't much. I'm hoping a valve adjustment will fix that.

When you do the compression check, do it dry and then "wet" meaning put a little heavy weight oil in there to temporarily seal the rings/cylinder bore interface. If the readings stay the same the problem is not a cylinder bore/ring sealing problem.

When it runs, and the oil fill cap is back on, does the engine sound peculiar or really shake around a lot? If not, I would be very surprised if a piston was shot, but that will show up in the compression test.

Sounds like the oil you use should be fine. The speed the engine reaches is a key to starting cold. Too slow and the cold block absorbs all the heat of compression from the air. Lots of starting excercise will weaken a starter, just as lots of glow plug cycles shortens their life.

I would check the valves and then the rest of the things you noted, including the injectors. A fine mist lights a lot better than a short, thick stream of Diesel. Timing should have been set when the chain was replaced, but it is worth another check if the valves are ok.

Let us know how you make out, and good luck, Jim

blow-by video
 

Hope it works, check this out...

http://i21.photobucket.com/albums/b2...h_MVI_0180.jpg

BTW, it's me shaking, not the engine...

My blowby looks basically the same, im interested to see what folks say.

I am not overly impressed by the blow-by you showed, but I thought the video was pretty cool. Same with the sound. These things will run with a lot more blow by than that. A good deal of the visible stuff is tiny oil droplets and vapors from the oil circulation being carried out by the blow-by.

When you go to put the cap back on, do you feel some resistance, like the cap is riding on a cushion of blow-by and you are having to squeeze the cushion out of the way? If not, I would categorize the blow-by you show in the video as mid-life blow-by rather than end of engine life blow-by. Good oil, frequent changes and you should not see this deteriorate rapidly.

But, do the valve adjustment and compression check you spoke of to get a better handle on the poor cold start performance. If the engine is barely running because of out of adjustment vavles, for instance, once you correct that the blow by may get significantly worse if suddenly the valve timing and sealing is improved, and the picture may change. If so, take another video and post it. That was pretty cool.

Good luck, Jim

Yes, there is definately some pressure.

Depending on how much resistance, you have a developing issue. I changed my oil from regular Mobil 1 15W-50 (used to be a red cap, quart bottle) to Delvac 1, 5W-40. Comes in a silver, gallon jug. Cost more, but it did wonders to revive an old 240D for another life after 250,000 miles. My son took it to college and drove it without any oil in the sump, ruining the engine, so it was retired at about 321,000 miles. It had a rear crank seal leak that was too expensive to fix, given the condition of the rest of the car, so you had to add oil and park with the nose downhill, but never add more than the half way mark on the dipstick or it just ran out.

Anyway, the point is, that oil cleaned the ring grooves and lands and the overall performance improved, making cold starting easier and making the engine run stronger. You might consider the same - Delvac 1 has special detergents formulated for Diesel engine abuse from by-pass and the like. I actually use it on all my cars, Diesels and gassers. You should also run the machine hard. Loafing Diesels get full of poorly burned junk that clogs and chokes the engine, and by filling the clearances in the ring to ring grooves, deteriorates the function of the rings.

Good luck, Jim

Thanks, Jim, will do. Oil change is due soon, anyway.

My Blowby is far worse than that. It will blow the cap right off. I think you have some life left in the engine yet.

- Peter.

Thank you all for giving me hope. I guess, I have some diagnostics to do now...

The engine seems to run fine, though, so if you listen to most of the folks on this board, you should ignore blowby. You can't do anything about it, so why worry? You should worry about compression, though. I'd check it and also inject air into the cylinders to see if you've got some burned valves. Good luck!