constant airlock issues

Ive just done the headgasket out of routine on my freelander, replaced the thermostat and housing and drilled holes in the stat as i used to on almost all Rovers/MG. Did all the gaskets and replaced all the clips.

The car is running fine, no splits, not overheating. I have noticed that upon startup i get a sloshing from the heater matrix indicating that somehow its getting air into it overnight.

Secondly i just cant get it to a high enough temperature for the fans to come on. I know they work - but even on the drive for about 5 minutes at 2500rpm it just wont go above halfway. Mind you, i suppose thats a good thing.

When its cooled and i remove the upper bleed screw on the heater matrix it doesnt instantly show water, however if i remove the coolant cap the system is under pressure as expected.

Any useful ideas?

Hippo said:

Have you got water in the air intake? Have a look in the 4 inch diameter pipe on the rhs in the pic in the passenger footwell.

Click to expand...

That didn't solve the problem then??

Acksurley from what you said this time I'd guess that you haven't refilled the coolant properly

Hi, no no water in the matrix pipework or on the floor. Filled it as per RAVE. It was fine past night with no noise - however today the noise was back. This is after a headgasket change.

what is it petrol or diesel and was head skimmed and crack tested and k series liners checked

fanatic said:

what is it petrol or diesel and was head skimmed and crack tested and k series liners checked

Click to expand...

Petrol, yes, yes and yes. I think i may have sorted it, i noticed a small hairline crack in the thermostat housing, took it off and replaced it this afternoon and it seems to have done the trick.

Is there nowhere else that water collects, say above the bulkhead etc?

Im still confused as to why a small crack causing a very very small leak (which i didnt notice, it was collecting on the IRD) could also cause air to get into the system.. as oppposed to just letting it get out. Oh well, im back at work this week so ill keep an eye on it and see how i get on.

pauldoubleyou said:

Im still confused as to why a small crack causing a very very small leak (which i didnt notice, it was collecting on the IRD) could also cause air to get into the system.. as oppposed to just letting it get out. Oh well, im back at work this week so ill keep an eye on it and see how i get on.

Click to expand...

If the coolant system is allowed to run without being able to pressurise, then you get localised boiling within the engine. This is where the mystery air comes from causing air locks and hot spots. Its normally a faulty coolant cap that is to blame but your crack would cause the same pressure loss.