MY97 WRX - Ok when driven quietly but take it for a 10m blast and the water is overflowing from coolant overflow. The temp gauge is normal until you pull over and then begins to rise. Normally the car comes up to temp within about 1.5m through a 30m limit, from cold. There is no water evident in the engine oil.

Any ideas?

Sorry if this has been covered a thousand times but can't get the search facility to work...

 

If there's no water in the oil, I take it there's no oil in the water either?

Sounds more than anything else like a stuck thermostat. Have you replaced this (or otherwise ruled it out as a cause of the problem)?

 

Are your fans cutting in correctly? Perhaps wire them in permanently for a day or 2 to see what happens, easy enough to do.

David API engines

 

Agree with Greasemonkey and David only other thing could be a worn water pump impeller IMHO
See if the radiator / hoses are all at same temperature if the stat is sticking I would expect the bottom hose to be significantly cooler than the top one

Steve

 

...the bottom pipe was cooler than the top when it over heated earlier! (read on another thread to check this...couldn't quite remember the diagnostic significance of doing so!)

...thanks for the replies (was expecting head gasket doom and gloom!)

 

...oh, sorry, haven't replaced thermostat and was unsure whether fans were cutting in correctly. Seemed to only cut in when the vehicle was stationary.