1996 Volvo 965 Heater control valve failure (disintergrated)

[dwhite66]

Just recently had the heater control valve on my 96 Volvo 965 blow apart while on a sunny Sunday afternoon cruise to visit a friend. Has this happened to any other 960 owners? Evidently I did not notice the sudden temp change until I saw the steam blow out from the engine compartment. Had the car towed home (thanks to AARP Roadside Asst), replaced the valve the following day, and now, it's cranking but no start and run. It seems there's air pressurizing the coolant expansion tank when cranking. Is it a blown head gasket, warped head or both? Perhaps something more serious and expensive? I bought this pre-owned a few months ago with 142k miles and have put quite a bit of work and love into it. It's a job that I am prepared to tackle myself although I would rather not have to because, once started, I know I won't stop with the head and may end up rebuilding the whole engine. It could get involved and expensive for me. It's sometimes hard to restrain myself for I am admittedly a heart and soul Volvo car enthusiast.

[93Regina]

heater control valve...blow apart...

My 93-944 did same thing, just after rebuilding a B23F engine, but I caught it on temperature gauge, before any head damage was done.

All you can do is pull head, and see if head/block have a flat surface...

[precopster]

So did mine in my 1993 wagon however I caught it in time.

[Salomons Driveway]

After the B23FT engine in our 740 overheated due to a leaking heater control valve, our mechanic told us that a compression test would show if the head had warped and demonstrated by cranking the engine.
Our engine cranked unusually fast, like a good engine would do with the spark plugs removed, and my first adventure with major engine work began! It is not likely to be just the gasket and the warpage tollerance is 0.05 mm per 100mm with no refinishing allowed according to the 1987 760 specs from a Haynes manual.
A compression test with the radiator cap off should show low pressure or no pressure increase with oil added to the cylinders.

[DEWFPO]

Have you run a compression test?

DEWFPO