bit the bullet.

Well after tinkering the weekend on the mystery machine I couldn't stop it purging coolant into expansion bottle and out onto road. Took it to garage to test head gasket. Just waiting for the result. :-[

Chemical head gasket test kits don't work very well on a hijet as there isn't a place where the gases accumulate.

If you get a positive, it has definately gone.
If you get a negative, it still most likely has gone.

Makes sense    

Passed the chemical test. There going to check all hoses now for blockage.

My red van passed the chemical test about 3 times but the head gasket had gone  

Reason is, you can't get a good gas sample of this type of system.

That's what I'm worried about is there another way to rule it out without stripping down. Haven't really got funds this side of Xmas. To sort plus at moment it gets me to work and back ok only ten minute drive.

A compression test maybe? Funny enough it didn't purge into the expansion tank while in the garage last night.

They don't tend to purge at all if you just leave them idling.

They only purge when under proper load, e.g. acclerating - due to the cylinder pressures.

I doubt you would see any variation in compression.

Prob not the case but they do it if its lost water, my old one did it on the way up from York, though only the once.

turns out the matrix is blocked so bypassed it and no purging. great just as winter sets in. at least I got two weeks off over crimbo to sort it. is there a guide on here somewhere to getting at it?

Why do  you think your heater matrix is blocked?



If you don't bleed them properly you will never in a million years get the air out of the heater matrix, as it's the highest point in the system.

If you leave them with a matrix full of air, then they will boil up and purge early, because the air is compressible, unlike if it was 100% full of water which is a far less compressible fluid.

You can test to see if the matrix flows ok, by using the pressure fill method  

Likewise you can 100% bleed it of air using the pressure fill method.

[quote="HighlyJetted"]Why do  you think your heater matrix is blocked?

because the man in oily overalls told me......lol
will connect back up while off and try the pressure fill method.
cheers hj.

http://www.screwfix.com/p/bottle-air-vent-15mm/34359
this is what I was thinking of plumbing in around the highest point. having not stripped out a dash not sure how much room there is.
what are your thoughts on this guys?

You don't need to buy anything or re-design anything.

It just need sorting properly.