Airlock in cooling system

ZXAuraTD · Post by **ZXAuraTD** » 19 Nov 2004, 18:21

Hi, im in need of serious help!
I've got an airlock in my cooling system that is proving a right pain in the..aye!
Followed all instructions, haynes, etc, cant seem to shift it. I sometimes get some of it out, and things start to circulate, but often, im getting massive back pressure, and sudden overheating.
Perhaps the thermostat isnt opening?
I'e heard that this could have to do with head gasket problems, but im really hoping it isnt.
Is there any way to get the air out completely?
My heater is also affected by this.
I cant drive my car at the moment 'cos im afraid it's gonna overheat bigstyle!
Please can anyone help?

beezer · Post by **beezer** » 19 Nov 2004, 18:28

Does sound like head gasket. Top hose will be pretty hard when engine is running. Pressure is likely to build up in expansion bottle. It is when you wrote of MASSIVE back pressure.

ZXAuraTD · Post by **ZXAuraTD** » 19 Nov 2004, 18:33

Thats what i'm fearing.
To be honest, i got the big back pressure the other day, and i thought it was knackered properly.
However, last night we got it going fine, no pressure, circulating nicely, took it out for half an hour, no problems at all.
So, drove to work this morning (been getting the train all week) and after 4 miles, the temp gauge suddenly shoot up almost to the top - i switch off and coast into a layby. Some coolant was pouring out of the overfill pipe thing. Not loads, but some. Didnt want to risk doing anything more with the car until later, so got a lift in.
Just a bit stuck really. Sometimes it works, and sometimes, like today, it really really doesnt.

NiSk · Post by **NiSk** » 19 Nov 2004, 19:16

Headgaskets are either blown or not blown - I've never heard of them repairing themselves. On the other hand, theromstats have a notorious habit of sticking. I'd start by replacing the thermostat, no, I'd do a cylinder pressure check first/as well.
//NiSk

beezer · Post by **beezer** » 19 Nov 2004, 19:18

Could be thermostat but I am pretty sure it is the gasket. Look for traces of oil in the water.

ZXAuraTD · Post by **ZXAuraTD** » 19 Nov 2004, 19:20

Cheers.
I've just sourced a thermostat this minute, i'll try that.
I like me car and i dont wanna have to take it to bits

(too much)
(as i know i'll never get it back together [;)])
P.S - no traces of oil, i've been looking out for that - could be a good sign?

arry_b · Post by **arry_b** » 19 Nov 2004, 23:25

Is your radiator cap *perfect*?

weety · Post by **weety** » 20 Nov 2004, 02:19

i had a bx once and the headgasket had blown out into the cooling system so it just over pressurised the cooling system all the time, no oil in water or water in oil just a small steady constant loss of coolant through the expansion cap--used to be able to drive it for about an hour and a half before it lost enough coolant (funnily enough tap water after the first few times) to overheat-- actually quite exciting what with no temperature gauge

beezer · Post by **beezer** » 20 Nov 2004, 02:21

I bet you were bubbling with excitement!

weety · Post by **weety** » 20 Nov 2004, 02:34

novelty wore of after a couple of months and i went and bought a xantia