Frothy coolant

[phedders]

Ok, got round to trying to bleed my coolant yesterday - found it was erm.. mucky and a bit sludgey so did the old run a hose through the system for ages and ages... all went well, now got some nice orange coolant in there - much easier to see in the expansion tank!

Now when bleeding (see saw) I get a few nice burps... but when the enging is running I get quite a lot of tiny bubbles in a kind of froth....

anyone got any ideas? I'm wondering if the water pump impeller is fading and causing cavitation - but maybe this is just perfectly normal? Certainly the pressure it builds up seems to be fine and the thermoV seems to work as it should...

[Simon Jones]

It is normal for the coolant from the bleed pipe to be quite frothy at first, but it should improve throughout the bleeding process. As the water reaches boiling point it can start to froth in the expansion tank - this (I believe) is normal & not to confused with head gasket problems which tends to be more 'volcanic'. I don't think you will have a problem with the water pump - I changed mine at 80K and the impleller was in perfect condition.

If you have bled it for at least 45 mins, then you have probably got as much air out as you can. When it cools down, check the level in the tank & expect to add up to a litre to get it back to the correct level.

[phedders]

Cheers!

[bigdaddycain]

I agree with simon, now if the water was foamy....