5 replies to this topic

[jonesn6]

Hi
New to Miniforum and hoping someone out there can help me!

I've got a Mini Cooper 04 and have been having problems with coolant loss.

Symptoms are ------

When the engine is started I can hear there is air in the system (gurgling/whooshing sound from behind dash in passenger footwell), and I'm constantly topping up water in header/expnasion tank. Investgiations show no water in oil (so head gasket sems OK) and no leaks udner car when left overnight. Engine temp is showing as 'normal' but it looks like teh coolant is being forced back up the tube from below the pressure cap back into the expnasion tank and then its forcing the cap off the expnasion cap and the coolant is overflowing down onto the exhaust manifold (and evaporating).

I've tried bleeding the system when engine is cold, using the two bleed valves and topping up water level down through the pressure cap (its removed) - and then when engine starts to get hot, tightening bleed screws and replacing pressure cap, and then top up expansion cap. When I trun engine on, the gurgling/whooshing sound of air seems to be much less (but not completly gone) - So I assume I can't be bleeding system properly???

But when the car is run for any length time the water boils back through the expansion tank again.......and the air is back in system!

Can anyone help me?

[Dan]

Head gasket failures frequently happen without breaking into an oilway.

[lawnmowercrap]

Best way to bleed modern cooling systems is simply to take the car out for a good thrash. We have to do it on most Vauxhalls to get them to bleed properly.

And bear in mind that its a pressurised system, so when its warm removing the cap will release this pressure.

If this dont help, then id be inclined to do a sniff test on it to test the head gasket.


Lee

[minidaves]

nightmare problem, try topping up in the proper filler not the little tank on the bulkhead, and i will guess it has a slight head gasket issue

[Punts]

When the engines warm, check that the thermostat is opening. If it's stuck shut, the engine heats up, the water can't circulate, boils and returns the wrong way. This could cause your problem

[BoboGib]

I've had this problem on old rovers when the thermostat wasn't opening proprly.


EDIT: Beaten to it.