Triumph Repair: overheating, blown head gasket, radiator overflow tank

Question
I've got a 1979 Spitfire. I just replaced the thermostat and water pump within the last few days, now the radiator overflow tank keeps filling and the overflow hose keeps getting blown out of the tank. Any ideas how to proceed?

Daniel

Answer
Daniel,

Have you checked the compression?  

How do the spark plugs look?  How does the car drive, before it overheats?

It could be either a)  blown head gasket or b)  the cooling system isn't keeping up with the heat the engine is putting out.

Does your car have the slant radiator?  If so, is the electric fan working?  

The compression test should help rule out a blown head gasket.  Checking the plugs will give an idea of whether there's a problem with either the ignition timing or mixture.


Cheers,

Jim