Greetings all

When I start the engine on my little 4x4 I can hear water gurgling/rushing somewhere -- I presume in the plumbing to the heater radiator in the car. It quickly stops. The heater is working OK and the water level is fine in the header tank (mine is on the side of the radiator, and is at tlhe same level it's always been). I can sometimes hear it after sitting with the engine idling too, such as at traffic lights, when pulling away again.

Two questions: I presume there's air in the system, but how do I get it out. I can see there's a bleed screw on the heater hose, but that is higher up than the level in the expansion tank, so surely opening that will let air in, not out. And second, how did air get in? Is this a sign of failing water pump perhaps?

Any ideas out there?

Pete

Bleed the system with the engine running to remove any 'trapped wind'!
That's why the bleed valve is at the highest point - air bubbles to the top!

Once there's only coolant flowing from the bleed valve, close it and top up the header tank again to the correct level.

Where the air has come from is another thing. Unless it's been there for a while and you've just noticed (perhaps after a service/coolant change?) there must be a slight leak somewhere, allowing a bit of water out at high temps, then sucking air back in as it cools. Possible water pump, worst scenario would be an internal leak somewhere, such as head gasket, but then you would expect a more noticeable water loss or other symptoms.

Ken

Thanks Ken

One piece of info missing was run engine until its warm enough for thermostat to open. Then the extra pressure developed in the cooling system (by expansion as it heats) pushes the coolant out of the air bleed. Also, with thermostat open any air trapped in the whole system reaches up to the bleed screw.

Job done, and I think successfully. The bleed screw was not at all tight, so it may well have been letting air previously back in as the system cooled.

Pete