Hi,

I recently had to remove the radiator to change the cambelt, I've put it all back together and it all seems to work lovely, however whenever I increase the RPM on the engine the pressure to the main hoses to the radiators increases quite markedly. Under high RPM they balloon a few mm above usual size and look close to bursting. You can visually see them expand slightly.

Does anyone have any idea if this is normal? Both hoses are getting hot as the car warms up, water is returning to the header tank, heaters blow very hot air, all seems ok as far as any potential air lock.

I have heard that if there is some sort of head gasket issue or similar the high internal engine compression can get into the water system and cause this, but there is no other evidence of head gasket failure.

Just to mention its a 93 WRX, with over 90k on clock.

Any help would be greatly appreciated!

Many thanks

 

If your hoses are expanding when you rev up, it could be a head gasket,

Remove the expansion tank cap (when cold) and allow the engine to idle untill warm. Rev the engine to about 2500-3000 rpm and you should see bubbles come up out of the header tank after the initial water loss has settled.

Get a coolant pressure test if in doubt, catch it soon and you'll save the heads.

 

Hi, thanks for taking the time to answer, so if I am seeing bubbles in the header tank under the conditions you mention then you're saying that this could indicate a head gasket failure?

Any ideas what else it could be if this isn't the case?

Think i'll try and get the coolant block test done tomorrow.

Thanks!

 

To me, it looks like a head gasket, thats all it can be imo

 

is it not forcing water out the expansion tank?

 

On a car that age, it might just be that the hoses are on the way out. Removing/refitting them onto the radiator won't have done them any favours either.

OTOH it might just be that the hoses aren't quite naturally aligned. i.e. there's a slight twist or similar.

J.