Hissing water tank

[phunkynova]

There is a small problem with the cooling system the temp is fine around 85 but after a run its hissing lightly and burbling lightly if I undo the res tank cap there is some pressure but no more than I would expect, with engine off I can put the cap back on and 5 mins later its hissing again.
I'm hoping its not the head gasket.

[Southie]

You may have an airlock, try flushing the system. Have you kept the heater matrix in your rally car or did you by pass it?

Could be a faulty cap.

Try a compression test if your still worried.

[phunkynova]

Thanks Southie, yes i still have the heater matrix and it seam to be working as there is hot air from it.
How would I best flush the coolant system ?

[swedge]

Unscrew the temp sender untill all the air is out the system too that sometime helps

Slackening the jubilee clips can help while the cars heating up as well to get any air out obviously tighten them back out when the water starts coming out

[swedge]

Have you tried running it without the thermostat in to see if it's sticking?

[phunkynova]

Ok I will give it a go tomorrow. This is messed up talk on two threads people will start talking about us

[swedge]

Haha I'll just come over n do it for you

[phunkynova]

Ticket at the airport lol

[swedge]

De ja vu

[mowgli]

try swapping the cap..

also try parking it up somewhere over some cardboard to see if there is a leak somewhere...

as for bleeding the system just make sure the heater is on the hot setting & undo the temp sender slowly and let any air out.

if the car runs hot, stick in a stat from an astra diesel. they run at 88 deg.

[MK999]

try swapping the cap..

I was wondering when we were going to stop shouting zebra lol

[phunkynova]

Problem sorted it turned out to be the header tank cap, fitted my spare one and Bob's your uncle no more witches brew :thumb:.