Topping up coolant

[bolton]

Hi all should i top up coolant with the car running through the pressure cap in the engine bay?
Because when i open the pressure cap with the car turned off coolant comes rushing out through it?
Cheers

[MR2 Rich]

ONLY open the cap when the car is cold. If you open the cap when cold and there is coolant there, it doesn't need topping up.

[bolton]

I opened the cap when it was cold and coolant came gushing out?
I hadn't used the car in 24hrs.

[MR2 Rich]

I sometimes get a little water, how much are we talking about?

[bolton]

It started coming out so i quickly put the cap back on.
It recently had a coolant change so could it be air?

[dexter]

You don't want any air in the coolant as it will most likely cause overheating problems. Jack the rear of the car up, open the two bleed valve in the frunk and attach plastic tubing to bleed valves and hang them to the bonnet. Now open the coolant cap (make sure car is cool) and fill slowly.

Also, start car and set heater controls to hot and allow car to warm up. Once warmed up the thermostat will open allowing the car to take more coolant which might be a reason for the air stuck in the car.

Not the most detailed advice but a brief guide if your coolant has air/ pressure.

(Sorry if you already knew this!)

[bolton]

So this rush of coolant out the pressure cap is only likely to be trapped air escaping?
Cheers

[dexter]

It's possible that trapped air is causing the pressure so burp the system to rid the pipes of air.

Post here if it continues to have back pressure and i'll have a think

[JD]

was this an april fools by any chance?