Coolant Boiling In Expansion Tank

[Guest jelleyhead]

The coolant was boiling in the expansion tank. So much that it was coming from the overflow pipe and from under the cap I didn't over fill the car with coolant. I put a new thermostat in it to see if this was the problem still the same.

 

Could it be that I need new caps for the radiator/expansion bottle as the could be air getting in.

Am going to run water through it to make sure it's not blocked anywhere.

 

Any other ideas??

[Guest 2b cruising]

Possibly an air lock in the system.

Can be a bugger to fill and get all the air out.

[knights_templar]

Could it be that I need new caps for the radiator/expansion bottle as the could be air getting in.

 

 

"caps" plural? you should only have one pressure/vacuum cap in a system, or they will end up fighting each other.

 

Is this a new fault, and previously everything was fine, or have you made some changes to the system?

Edited July 10, 2016 by knights_templar

[Longboarder]

When did this happen? While you were driving along or when you had come to a stop after a run? If after you stopped how long had you been stopped and was the engine still running?

 

Nigel

[Guest jelleyhead]

Knights_teplar. To answer your question I have two caps one on the radiator and one on the expansion tank.

This is how the car was setup when I got the car.

I put a new radiator in it about 3 mths ago due to my old one weeping but didn't have a problem .

 

Longboarder. I had been in the car for 5/10 min as went to put petrol. I then had problems with the starter motor as something came up from the road and hit the starter breaking the wire so was pushed to the petrol station till I sorted that so the car was sat for around 30/40 min not running then when taking the car for a drive this problem occurred I checked the radiator over I couldn't see any damage there.

 

Thanks Darren

[Guest Gargoil]

Try taking the new thermostat out and running it without one. Keep an eye on the temps and if all OK fit a new stat. Is it a suck and blow system or a fully pressurised one?

[kevin the chicken]

Is the cap on the radiator just a blanking cap. You certainly don't need two ordinary ones

[Guest jelleyhead]

It's suck and blow system. Nether one is a blanking cap. Should one be a blanking cap then ?

[kevin the chicken]

The one you don't fill up through, which I presume is the radiator can be a blank cap. My radiator is lower than my header tank so I never use it has the blank cap on. Doesn't really explain your problem unless one of the seals in the caps has failed.

[Guest jelleyhead]

I will order a blanking cap see if this helps thanks I appreciate any advice.

[alanrichey]

Don't know how much of the original Superspec cooling system you retained, but I suffered from boiling when the pressure cap wasn't working properly. And I also had a leak under pressure so the coolant level was always low, with plenty of air in the system. Fixing the leak, removing all air locks and fitting an uprated (21psi) cap on the header tank and no more problems.