Hi!
I recently had the head gasket changed in a garage (ouch!!). Since then, the car is making much black smoke than before. No smoke when running at constant speed or idle, but a big big pouff when starting from a red light. Peaople behind car are annoyed. Someone even stopped my wife to tell her the pb !
I have changed all filters. No change. When changing air filter, I discovered than there was a small hose between the top of the engine and the inlet air big tube which had been changed and was not attached correctly (too big diameter). It is full of oil and a lot of oil also in the air inlet tube.
Can this be the cause of the black smoke ?
Thanks a lot
Daniel
- (#524) Daniel, 4 Apr 05 17:53
Nope. That's the crankcase breather. You've too much fuel or too little air; there could be something stuck in the air intake, or a problem with the diesel pump- or perhaps the garage set the timing up wrong when replacing the cambelt?
- (#524) David Miller, 5 Apr 05 01:55
Thanks again David,
I still find I have a lot of oil in this air tube coming from the crankcase breather. Does this go to the injectors?
- (#524) daniel, 6 Apr 05 03:03
No. It's condensed vapour caused by blowby, and is pretty normal. If the blowby is excessive then there is a possibility of overheated rings or a cracked piston caused by a previous overheating episode. But oil smoke would be blue, not black...
- (#524) David Miller, 6 Apr 05 03:32
I had these symptoms. When I got the car the engine was very oily and I discovered that the little hose was split at the engine end. Then I discovered that a hole had been chafed in the big hose, under where the little one joins it, by rubbing on the top of part of the EGR assembly underneath. I renewed both hoses and the engine/bay stayed clean.
The big hose carries air from the air filter as it is sucked into the engine via the turbo. Oily vapour is sucked out of the engine valve cover into the big hose. Passages connect down inside the engine between the valve cover and the crankcase and so the little hose sucks any surplus funes from the crankcase too - hence it's called the crankcase breather. Nothing to do with injectors.
If I ran my engine with the little hose off there was a lot of oily misty blown out of the valve cover. Eventually I discovered that this was because, probably from when I bought it, I had a cracked piston which allowed combustion pressure down into the crankcase which was blowing the oil out the little hose. However all this oil - sometimes half a litre in 1,000km - was happily ingested by the engine with hardly any sign of smoke or any other symptoms than oil consumption. Until the piston got really bad and oil consumption went up to a litre in 200km.
Is your oil consumption high, Daniel?
- (#524) Dave Mason (Sussex), 6 Apr 05 03:40
Thanks again David and Dave,
this is a wonderfull website. Your explanaions are very convincing.
I will replace this small hose anyway because it is loose, but I understand I have to find something else.
My oil consumption is about 1/2 liter for 1000km.
My worry is that before I had the headgasket changed, there was no smoke and no oil consumption.
My mechanic does not want to touch to the pump screws, he would like to clean the injectors and is asking a couple of hundreds Au $ for that. I would like to try simple things myself first, if any.
Disconnect the EGR seems to be one. Then, I undestand there are 2 screws on the injection pump, one on the top and one on the back...
sorry about my english,
Daniel
- (#524) Daniel, 7 Apr 05 06:01
Oh, I forgot to say.
After the headgasket chnage, there was another difference:
the green turbo light does not come on any more.
- (#524) Daniel, 7 Apr 05 06:49
Woah horsey then. How's the performance? Sluggish?
Check out the picture in the archives of vacuum hose routing. One of the narrow hoses is mis- or dis- connected.
Check especially the hose from the inlet manifold (under the big air pipe) to the top of the pump and the boost switches in front of the air cleaner housing... Make sure and poke a pin or wire into the spigot on the inlet manifold. It's only a fine orifice, and if it's partially blocked it won't help...
- (#524) David Miller, 7 Apr 05 11:19
OK. I come back from the autorepair shop. They found they made a mistake when connecting the vacuum hoses.
You were right! Now the green light is coming.
But they also wanted to check the timing because I told them it was smoking. They found that the timing was moving !! They changed the belt last time when they did the head gasket. Now, they don't know what is going on. They don't understand why the timing is moving. Belt is new and tight...
- (#524) Daniel, 8 Apr 05 04:41
I'll presume that we're talking about static timing, and that the shop knows to defeat the cold advance lever? Also that the pump is indeed tight.
I'd pull the various pulleys to confirm that the locating keys haven't broken or been misplaced.
Now if it's the dynamic timing they're talking about, the pump is duff. Simple as that!
- (#524) David Miller, 8 Apr 05 10:44