1990 740 turbo smokes

i just got through replacing the head gasket and having the head reworked on this car, when starting it, it wont idle, so we adjusted the idling, then when started it throws out alot of white smoke, it doesnt smell like oil or gas, i think it is water vapor. the car lost alot of water inside the motor when the head gasket blew, i emptied the oil pan and the motor had probably 2 gallons of water in it, could the air cooler for the turbo got water in it, and it just burning it out? also we have changed the oil like 4 times since changing the head gasket, so there is no water in the oil. could i have a blown turbo?

Reply to
saintsfan2200
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The turbo is possible, but not my first thought.

You need to determine whether something is still wrong or if it is trying to recover from the previous failure and the fix.

The crucial issue is whether it is consuming coolant. If the coolant level is dropping steadily (it can drop suddenly once or twice burping out bubbles of trapped air) there is something wrong. If not, it is very likely burning off water (coolant) that got somewhere it didn't belong earlier.

Another important question - especially if coolant really is disappearing) is whether coolant is getting into the combustion chambers in spite of the repair. A quick confidence test is to remove the reservoir cap and have somebody start (or at least crank) the engine with the palm of your hand over the reservoir. If you feel pulsing pressure when it is cranked and/or steady or pulsing pressure immediately after the engine is started, that is bad news. The head has to come off again and you have to find what went wrong there.

As for the turbo, you can remove the inlet hose (the big one on the front) and look for signs of coolant in there, and remove the outlet hose on the top of the turbo and look for droplets in the hose. Checking the exhaust side is a lot tougher, but since you mention trouble idling it is less suspect, too.

Finally, coolant in the exhaust has the sweet antifreeze smell. Are you getting that?

Mike

Reply to
Michael Pardee

The exhaust and muffler are probably full of antifreeze from the head gasket failure. Let the motor runn outside for a while and see if the volume of smoke starts to decrease after a while. If it does, run the car on the road for a while. Stay out of the boost if you can and see if the smoke doesn't keep decreasing in volume. If it does then you'll just have to run it enought for all the antifreeze in the muffler batting to "burn" off.

Bob

Reply to
Robert Dietz

yes it is a sweet smell, and yes there is an oily milky sludge inside the big pipes going into the intake, could the air cooler be full of water?

Reply to
saintsfan2200

I suppose it's possible. I've never tried to drain the intercooler, but I think it can be done. Be prepared for at least oil and probably at least some water to come out.

The hoses usually have an oil coating from the crankcase vapors, but normally no water. I'm wondering if the milkiness came from the original gasket failure dumping so much water in the crankcase, where it boiled off and ended up in the intake.

If the coolant isn't disappearing and the engine is running okay enough, I'd favor Bob Dietz's approach of idling the engine to see if the leftover coolant burns off a bit, then driving it gently to complete the process. After all, either something's wrong or it's not.

Mike

Reply to
Michael Pardee

Yeah it happens, even on a normally functioning car the intercooler gets some oil condensation in it. I pull mine out and drain it every couple years, it's not hard. Just remove the two hoses and take the two brackets off and it should lift straight out.

Reply to
James Sweet

hey guys i really appreciate the info u have given me, the intercooler was full of water, we emptied it but it still smokes, i think it is could be vacumn. would having a vacumn hose off cause it to throw out smoke? or is my rings bad? could the high water level cause the rings to go bad? and is there a fix, short of an overhaul? thanks again

Reply to
saintsfan2200

Vacuum leaks don't usually produce smoke.

A few questions...

1) Does the smoke appear almost immediately after the engine is started, or is there a delay - and if a delay, about how long? 2) Has the engine smoothed out, or is it running badly either at idle or when revved? 3) Is a lot of coolant or oil disappearing? 4) Is that smoke or steam coming from the tailpipe? Steam dissipates by the time it is a couple dozen feet away (farther if the humidity is really high), while smoke drifts in clouds that don't fade much. 5) Have you let the engine warm up completely yet?

Mike

Reply to
Michael Pardee

the smoke sticks around, i havent lost any water, just a little oil, it smokes alot on deceleration and acceleration but not at a constant speed, ans yes i drove it like 30 miles

Reply to
saintsfan2200

Hmm... I think we can say it is oil smoke then, and not from oil accumulated in the exhaust during the previous work. The good news is that there is no reason at this point to take the head back off.

The question is whether it is oil getting in the intake, into the combustion chamber around the rings or valves, or whether it is getting into the exhaust from the turbo.

If the smoke starts as soon as the engine starts (or within a minute or so, at least), that smoke isn't coming from the turbo spilling into the exhaust because the exhaust isn't hot yet. Take a look at the spark plugs for signs of oil on them anyway - it would help to know if all the plugs have oil, none have oil, or some do.

Just as general practice, I also recommend cleaning the oil out of all the intake ductwork (just wiping it out is fine). If there is oil in the throttle body, give the TB a good wash with carb cleaner. Dirty throttle bodies are enough trouble as it is without adding a bunch of oil to the problem.

Also clean the crankcase ventilation - the hose and the oil/air separator under the intake manifold. That separator should have the "blow into it" resistance you'd expect of about a 3/8 inch hole. If it or the hose is restricted, blow-by will build crankcase pressure and the oil will back up in the turbo drain. In mine it happened at idle, but after 30 seconds of cruising the smoke cleared up. Acceleration would also make sense for that problem.

Give those a try and see where we stand.

Mike

Reply to
Michael Pardee

i checked 2 of the plugs and they were clean no oil on them at all, also i was wrong about the smoke it usually starts smoke2 to 3 minutes after the car is started, longer if it idles. there is no oil in the intake pipe, but i found a vacumn hose that was left off im not sure where it goes, there is nothing open, also it seems that the valve cover gasket is leaking or the oil fill cap is leaking. i appreciate all the help you have givin me, are you a volvo mechanic?

Reply to
saintsfan2200

Not a Volvo mechanic, but Volvo owners have to learn a little to make it through ;-)

The delay strongly suggests the smoke is starting when the exhaust gets warm enough. That agrees with the plugs - the oil isn't getting onto them either. The other symptoms of the valve cover gasket or oil filler cap leaking complete the picture of crankcase pressure building up, which will force oil out of your turbo into the exhaust. Be sure the oil/air separator is not restricted (you will have to unbolt it from the block to do anything with it, and then you will probably need to replace the O rings on the underside), and that the hose is clear and it connects to the turbo intake.

Can you describe the vacuum hose (size, length) and if it is still connected at one end, where?

Mike

Reply to
Michael Pardee

very small hose, no neither end was connected, it was laying on the battery where we had takin it off and didnt put it back on, it about 6 to 8 inches in length and very small diameter. where is the air/oil seperator go into block?

Reply to
saintsfan2200

Hmm... the short hose doesn't ring a bell.

The oil/air separator is a plastic box under the intake manifold. If you follow the fairly large hose that runs from the turbo inlet across the engine and ducks betwen the #3 and #4 branches of the intake manifold, it will lead you to it. There are two short screws with 10 mm heads that hold it down. They aren't terribly hard to get to, but it is good to have a magnet ready to catch them if they try to get away. The bottom of the separator has a short plastic fitting that actually extends into the block, so it takes a bit of pulling and twisting to get it out.

Mike

Reply to
Michael Pardee

on my wife's car the oxy sensor was the problem I thought it was the turbo but it was the o\s .A good rev out too helps but only when warm then drive till the turbo cools down then idle and off .Just use the lower gears no need to speed .As well a litre of diesel to a tank every 10.000 klm or 6000 miles helps the injectors clean up well and doesn't mess the oxy sensor up . "Robert Dietz ioip.com>" In article

Reply to
John Robertson

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