240D locomotive - PeachParts Mercedes-Benz Forum

soothappens · #1 01-07-2010, 01:31 AM

I tried starting my car in the cold with no luck (40 degrees +/- ) I remembered another post about removing the oil cap so I did . During cranking more smoke was exiting the valve cover than the exhaust !! She did spit sputter and finally start but it reminded me of a steam engine.

A solid cylinder of white smoke. When it didnt start the first time perfect smoke circles where exiting .

Question : do I have major engine problems or is this normal on a tired engine ? It runs smooth when warm no noises or driveability problems . I havent a clue how many miles are on it and has always been hard to start below 50 degrees. Lately harder .

It has been sitting since october . Two glow plugs had went out and no time to mess with it. Replaced 4 before trying to start it reamed the pre chambers and they where clean . Head gasket was changed last year and valves where adjusted with head gasket . Rechecked them about 6 months ago while cleaning the injector tips . The car was running great. The smoke has got me concerned though.

Where do I go from here ? Add a stack and a train horn , or start looking for an engine ?

billhard · #2 01-07-2010, 02:00 AM

The only way I can understand how removing the oil filler cap would help the car start is if your valve cover breather tube is somehow clogged. I know if you block that on even a warm running motor it will shut the engine off.

I am sure someone smarter than i will respond to your post but in the man time take a look to see that tube is open.

soothappens · #3 01-07-2010, 02:33 AM

Quote:

Originally Posted by billhard

The only way I can understand how removing the oil filler cap would help the car start is if your valve cover breather tube is somehow clogged. I know if you block that on even a warm running motor it will shut the engine off.

I am sure someone smarter than i will respond to your post but in the man time take a look to see that tube is open.

The breather tube is the simple one it goes from the valve cover to the intake no oil seperator just the hollow tube it is open though . I think barry had posted that the pressure overcomes the vacuum shutoff. internally I'm guessing.

the hard start has always been there when cold just the tremendous amount of smoke is what surprised me. I didnt remove the cap when it was warm due to the oil spray. so I dont know if it gets better when its warm . After I started it I drove it for over an hour.

t walgamuth · #4 01-07-2010, 05:54 AM

It sounds like normal tired engine blowby.

johnathan1 · #5 01-07-2010, 05:57 AM

It should be about the same, if not a little worse once the engine is warm...

At least that's how every diesel I've owned has behaved. Your blowby sounds pretty standard to be honest.

layback40 · #6 01-07-2010, 06:04 AM

Just remember, one day you will have enough blow by to run the engine !! Thats when the fun begins.

soothappens · #7 01-07-2010, 08:14 AM

Quote:

Originally Posted by layback40

Just remember, one day you will have enough blow by to run the engine !! Thats when the fun begins.

Thanks guys !! Thats what I was hoping for . What would be disaterous on most cars as far as blow by seems to be the norm on these. So no worries "yet". Now what layback40 posted is what I was thinking RUNAWAY

. I was reading whunters thread on the runaway diesel and my engine seems like a good candidate. Especially with as much oil as I have in the intake.

Theres no miracle in a can for this one I suppose??

daw_two · #8 01-07-2010, 08:54 AM

Quote:

Originally Posted by soothappens

Theres no miracle in a can for this one I suppose??

Actually....I think if you ran the valve cover breather hose to a "catch can", you might avoid the RUNAWAY. You might need to install a sizable "catch can" though.

bmwpowere36m3 · #9 01-07-2010, 09:35 AM

For a cold, worn engine it's normal. You can check again when the engine warms up to see if it improves (piston rings should seal better as they warm up and expand). Oil won't shoot out of the cap, so don't worry.

The two best tests to really determine its condition are a leak-down test and compression test. The engine might also just need to be "cleaned" up as rings get gummed up from deposits (bad fuel, low rpm operation). Running the engine hard (italian tune-up) and water injection both should help out.

kerry · #10 01-07-2010, 09:47 AM

I remember the thread where one poster's car failed to start until the oil cap was removed then another poster discovered the same thing. It was an odd situation with a number of hypotheses floating around to explain it.
I think most of us have no idea how much smoke comes out of the oil fill hole when starting in cold weather because almost none of us have experimented by removing the oil fill cap in those conditions.
It's below zero here this morning so my car is plugged in. In the future, on a cold day, ( I don't consider 40 degrees cold, by the way) to see what happens.

toomany MBZ · #11 01-07-2010, 12:35 PM

Quote:

Originally Posted by bmwpowere36m3

The two best tests to really determine its condition are a leak-down test and compression test. The engine might also just need to be "cleaned" up as rings get gummed up from deposits (bad fuel, low rpm operation). Running the engine hard (italian tune-up) and water injection both should help out.

Yeah, except the water injection part, I understand some gassers can be helped by that, not so sure on diesels.
Adjust the valves first.

bmwpowere36m3 · #12 01-07-2010, 02:27 PM

Quote:

Originally Posted by toomany MBZ

Yeah, except the water injection part, I understand some gassers can be helped by that, not so sure on diesels.
Adjust the valves first.

Even better due to the temps and compression, it's like a steam cleaning for the inside of the combustion chamber... better than any of the fuel additives. Very popular with FI crowd both gas and diesel. *
You should see the insides of some of those engines after a few miles, very clean.

A valve adjustment should just be a given when diagnosing a new motor, but it wouldn't cause blow-by (PCV). Well, actually combustion pressure could leak through the manifold and travel back through the breather hose into the valve cover and out the oil cap (if you’re checking through the oil cap). *

Disconnecting the breather hose from the valve cover will leave blow-by purely from the rings. *If you have the manifolds off, you can listen for popping or look for smoke out the cylinder head. *Then you’d be losing combustion pressure through the valves. *I did that on a worn 617NA that had a ton of blow-by. *Compression was decent on all but one cylinder, and leak down tests indicated both rings & valves. *With the intake and exhaust manifold removed, you could hear popping and see smoke. *Disassembly of the motor showed damaged/worn rings, and a bunch of burnt valves.

Codifex Maximus · #13 01-07-2010, 02:29 PM

soothappens:

Did you do a compression test? Could just be worn valve guides letting oil into combustion chamber.

soothappens · #14 01-07-2010, 05:45 PM

Thanks for all the replies. I did a compression test after replacing the head gasket I used the glow plug hole all cylinders were at 225 when cold I think mercedes calls for the 300 range for acceptable levels so shes worn. Cylinder walls looked ok when I had the head off no cross hatch watsoever . The water injection is beleivable because when I removed the head the cylinder that was getting water in it was the cleanest. I did do a diesel purge about a month before , I found it on diesel giants site. This smoothed out the engine considerably. Then the glow plugs quit.

I have been using it all day plugged it in this morning for two hours and it fired on the first crank I glowed 2 times. Temps were in the 30's . All day its been starting on the first or second crank right after the glow light turns off. went to five diffrent places and she started like a gasser. It has really impressed me ! As for the smoke it does calm down when warm still smokes but no where near as bad. I guess the glow plugs helped considerably I also did the italian tune up last night dont know if it helped but it releived the stress of trying to get it started !!

Could the engine get that gummed up from two glow plugs out ? I'm also wondering if it does have low compression why does it lug the starter down so bad when it doesent fire you would think just the opposite would occur?

I also tried to vent valve cover with just a blow by hose like the big trucks but it fills the cabin with smoke when windows are down and tends to piss off people at traffic lights.

kerry · #15 01-07-2010, 06:01 PM

Quote:

Originally Posted by soothappens

Thanks for all the replies. I did a compression test after replacing the head gasket I used the glow plug hole all cylinders were at 225 when cold I think mercedes calls for the 300 range for acceptable levels so shes worn. Cylinder walls looked ok when I had the head off no cross hatch watsoever .

That doesn't sound good. 225 is very low. You should have cross hatching. If you don't, the cylinders are worn.