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?

 

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

 

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

 

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?

 

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

 

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.

 

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

 

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

 

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

 

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

 

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?

 

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

 

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?

 

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

 

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 .