Pressure build up in cooling system

[Dazco]

The cooling system on jambos is pressurising big time (early 1.9 dg Petrol watercooled). I'll be having a sniff test done and expect it to come back positive. I take it this means cracked head allowing exhaust gasses into the coolant system . Are there any other causes of this ?
Im fearing this will involve an engine strip down and im worried about all the pit falls that can and probably will ensue.
It would have to be a case split to replace camshaft bearings as these are rumbling a little ( Andy at Campershack pointed this out the other year ).
As a result im looking into the possibility of changing to a 2.0 l na Subaru, are these engines ok running on LPG ?
Plan would be to buy a decent runner probably a Forester, run it for a month or so while I'm stripping the old engine out of the van and buying the bits for the conversion.
I would ideally like to keep the LPG system and use on the subaru.
Thoughts and ideas more than welcome. ( limited funds)
Thanks

[itchyfeet]

I think it would take a very trained ear to distinguish between cam bearing failure and general tappet noise.
My reccomendation as funds are tight is to strip and reseal the wbx, gasket set is under 100 quid, got to be worth a go.

[Dazco]

After seeing Andys work on my van a couple of others i trust his diagnosis re the cam 100%. I don't feel confident enough to open the case, that might be a step too far.

[kevtherev]

Can we assume the header cap is working ok?

[Dazco]

Good point Kev, I'll stick my spare on later ( known to be ok and from BW)
Jobs for today:- cold compression test , warm comp test , bleed system , new cap .
Sniff test Tuesday. I'll try and get some pics of the coolant level as well after bleeding and then after a short run.

[Dazco]

Positive sniff test . Exhaust gasses in the coolant. I'll do compression tests this evening .

[kevtherev]

That's bad news.
Best be prepared for a head replacement.

[ajsimmo]

Compression sealing ring more likely than cracked head. If it's not had correct coolant all its life, head removal is a big risk. Be prepared!
How about just fitting another wbx? Subaruining and limited funds are not usually happy bedfellows!

[Dazco]

Thanks for that but buying a used engine will, I would have thought, result in the same problems or worse occurring again in the not too distant future. As mine would require a case split, which im not confident in doing I would be opening a big can of worms. Ive priced the parts for a full rebuild to do it properly and it's just a no go. Scooby route is now in progress , got a few months to save for parts etc