Hi guys, just got a Volvo 940 GLE non turbo the other day. It has a leaky heater core, which I'm intending to fix, but the issue that's just happened is that I was driving with the heater on full, which was not getting warm. Then my top coolant hose blew open from the engine to the radiator. Is this just a simple fix or a sign of something more? Maybe a head gasket?

 

I would suspect a loose hose clamp first and foremost. With the engine cool, I would tighten all hoses/clamps and then drive carefully and see what happens. While a head gasket can cause a hose to blow off due to pressure, a better way to check is see if you have a lot of white smoke out the tailpipe (more than just the usual white vapor from a cold engine start). Also with the engine cold, take off the cap to the coolant reservoir and then start the engine. If you see a lot of bubbling in the coolant in the reservoir then yeah, the head gasket is bad. Good luck.

 

With the leaky heater core you cannot correctly diagnose the cooling system or the head gasket. You have to bypass it first, or replace it. Bypassing it first is the way I'd go.