Pressure building up in coolant system.

Hi there. I'm new to here. Ive just bought a 2004 1.8 freelander. Everything was going fine untill I stopped at traffic lights to see steam coming from under bonnit. I pulled over to find header tank just about empty. coolant everywhere which looked to have copper filings in it. All pipes were rock hard. My first fought was the dreaded head gasket. When I opened header tank most o of coolant came back into it. Since the I have flushed though rad and pipes and changed thermostat which hasn't helped. No sighs of HGF in oil or water. And temp stays at half. Any ideas.

:welcome:

fit a new pressure cap

Originally Posted by THEengineer
AS SAID THE GAYLANDER SECTION WOULD BE MORE HELPFUL,but one easy check to do if when the engine is stone cold,if you get your water hoses rock hard and a lot of pressure when you remove your header tank cap its a very clear sign your head gasket has failed,they dont always fail with oil mixing with water


Hoses are not hard when cold only once I have been for a run and heated up engine. If just started and left idling hoses heat up but no pressure builds up. Hose coming from bottom of rad to thermostat stone cold all the time.

Have you checked for cracking around the coolant tank cap? They are known for crazing there.

temp guage does stay at halfway, even when it's obviously overheating, so isn't much of an indicator tbh.

oil does not typically mix with the coolant either, it tracks down the inlet and gets burnt in the cylinders.

it could just be a case of an airlock in the system, they are reknown to be extremely difficult to bleed. check the how to by doing a search using the aptly named search button.

Mine had the same issue... had it in the garage to sniff check and pressure check.

Turned out to be the water pump, it was leaking and allowing air in...

Initially presented as steam and no water in expansion. On refilling and running expansion tank over pressuring and throwing water out the cap. When switched the engine off you could hear it boiling in the top pipe and can physically see the water drop out of expansion tank.

The garage was able to pressurise the cooling system and tracked it down to the water pump.

No HGF thankfully, spotted straight away and not ran dry !