Under pressure

[Mack]

Right, my head is now removed and a new one fitted. However, on start-up there is instant pressure in the system, which is likely to blow a hose and/or blow the engine. The garage are investigating, but seemingly getting nowhere. This is costing me loads and I still don't have a van to drive! Thoughts?

[haydn callow]

They haven't fitted it properly.
The top face of the engine block isn't true.
Faulty new head..( is it a cheap one from China ?? )
Could the engine block be cracked ( would this cause the cooling system to over pressure )??

Anyone else got suggestions

Is the garage Bongo approved ??

[Mack]

It's the one that used to be at Churcham - so loads of Bongo experience. I'm getting worried....

[haydn callow]

What does the garage think ??

[Mack]

They are baffled - checking everything, or so they say. When I phoned today said he was stripping down water pump. I'm out of my depth. I don't think he is incompetant, as he has done good work for me before and I think he is genuine and honest, but I took van in for service and MOT. It passed with a bit of work and I mentioned the regular loss of a little water - two weeks later, I still have no van and he doesn't know how to fix it. I love that van, it was running sweetly and now I feel as though the garage has buggered it up!

[francophile1947]

Sounds like a botched head job Can't see how the water pump could pressurise the system to that extent
If they do MOTs, they should be able to do a sniff test for exhaust gases in the header tank.
If you were only losing a little water, why was the head changed? More likely a pin hole in a hose or water pump seals.

[haydn callow]

You don't strip down a water pump...You remove it and either replace it or change it.
Had it ever overheated before you took it in....how much coolant did you used to have to put in ? Did the level ever drop below the in/out pipes. Why was the head changed ??
Could it simply have/is been a airlock all along.

[haydn callow]

Athey the same staff they had at Churcham ??

[Simon Jones]

Sounds like same problem I had first time I stuck the head back on: it was pumping out worse than before from the bleed pipe. Assuming your head or cylinder block isn't cracked, then it is probably going to need the block to be 'decked' & use of correct type of gasket sealant. See my post below & the two links from it for details on these.

http://www.igmaynard.co.uk/bongo/forum/ ... =+wellseal

Fingers crossed for you.

[haydn callow]

WI.m wondering is...why did they change the head ??

[missfixit70]

See here for a bit of further info on the history of this one - http://www.igmaynard.co.uk/bongo/forum/ ... 26#p269726
And here - http://www.igmaynard.co.uk/bongo/forum/ ... 39#p272139 .

[Mack]

He said he suspected the head was the problem. Took it off and had tested in an engineering place in Cheltenham. Said it had cracks and in his words was porous. I was just losing about quarter pint per month. Sometimes when cornering the alarm would sqeak so I'd top up. Apart from that it was sweet as a nut.

[dandywarhol]

Did they use a genuine Mazda head gasket? I've known spurious ones to pressurise the system instantly with a new head fitted.
I've also seen a dodgy IZEURA supplied head (Chinese) whee the bolt holes didn't line up..............