Coolant pressure

[kulster]

I thought the expansion bottle caps go faulty ?, they have some sort of spring in them

[Monkeymagic]

They can but having seen many people chase these symptoms and replace bits a quick test could give you a quick answer either way.

[poor-boy]

Just thinking.. could I take the car to an MOT station and check the coolant system using an exhaust gas analyser?

[stocious]

Drive the car until it over pressures, let pressure out of expansion tank slowly without scalding yourself.. Just crack the cap and let it vent, when the pressure is gone, tighten down the cap and start car and let it idle for a bit, if it pressurises instantly, good indication of a cracked head/head gasket failure.

Don't burn yourself

[poor-boy]

Drive the car until it over pressures, let pressure out of expansion tank slowly without scalding yourself.. Just crack the cap and let it vent, when the pressure is gone, tighten down the cap and start car and let it idle for a bit, if it pressurises instantly, good indication of a cracked head/head gasket failure.

Don't burn yourself

Cheers for the info

It has pressured before and once it has dumped some coolant it continues to drive as normal. The coolant is always filled to the minimum line on the expansion tank and the whole system bled etc

[Monkeymagic]

The Mot station idea Will work. Failing that i can do a sniffer test for you if you are ever over worcester way. Free of charge of course.

[poor-boy]

Cheers Steve :thumbup:

Let me get these few shifts out of the way and sort something.

[SE_30]

Taff, another idea. Check for dirt / sludge inside the nipple on the rad, the one that the recirculating hose to the header tank is fitted to. I’ve had the same head gasket symptoms and inside the nipple has been filled with crud, not letting the water circulate in the system, pressurising the water in the header tank. Worth a try.

[poor-boy]

Taff, another idea. Check for dirt / sludge inside the nipple on the rad, the one that the recirculating hose to the header tank is fitted to. I’ve had the same head gasket symptoms and inside the nipple has been filled with crud, not letting the water circulate in the system, pressurising the water in the header tank. Worth a try.

Cheers Stuart - The entire system was flushed and is free flowing.

It may well be the head but will investigate into it

[stocious]

What about the rad , did you flush that ?

[poor-boy]

Yes bud, the entire system was flushed out.

[Acidburn]

get it checked out and do the sniffer test on it asap, it will only cost you more in the long run.

[poor-boy]

Cheers Peter.. Don't want a repeat of the long AA job lol

[bluequattro]

Get a sniff test at a garage, shouldn't cost much and if it's a no result then start looking for other problems
How long does it take to pressurise?
I would imagine it to go quickly if head gasket
AA tested the cap in my landy but symptoms persisted after changing it and sniff test confirm gases in water
If it does it after a drive and stopping car could it be after run pump?

[poor-boy]

It takes some time (days) before any pressure, it drives fine, no overheating or anything.. just chucks the coolant out every few days.

Next few days off work will get it looked at.