1988 Volvo 740 with Turbo, 188K miles. Driving up a hill, there was a poomf sound from the engine and white smoke started billowing from exhaust. Shut engine off, restart, has rough idle and some smoke from tailpipe, Start driving and lots of smoke. Let engine cool down, starts fine, idles nicely, no smoke. Drive about a block and lots of smoke. Visual check of engine (cold) found lite whiteish smoke pulsing from oil fill hole in valve cover and dip stick tube. No coolent found in oil pan.
My question is, short of complete teardown and inspection (which I’d rather not do), how can I determin if it’s a blown head gasket, cracked head, broken rings, broken/cracked/holed piston, or something I havent thought of yet?
I’ll take this one.
Volvo turbos will sometimes fail head gaskets when under boost (going up hills)
Assuming that the smoke was pure white in color and not white/blue, then the most likely cluprit is a blown head gasket.
did you notice any smell to the smoke? Coolant tends to smell “sweet”, oil smells well like oil.
How much coolant is in the resivor tank? Any?
Pull the dipstick, and check for coolant. (there may or may not be any depending on just how the head gasket blew)
From having rebuilt many of these engines I have developed a quick and dirty way to diagnose these engines
Look at the top of the engine block (the red painted part) just below the cylinder head below and behind the thermostat housing. What color is the red paint?
Light brown = blown head gasket
Dark brown = warped head
Black = damaged block (rebore and new pistons)
Also look at the rad. sometimes when the head gasket goes, it blows off one of the side tanks on the rad.
Hope this helps, feel free to e-mail me with any further questions.