Landy 110 petrol to diesel conversion

I'd say head gasket as it's showing no symptoms of a cracked head

From what I know of these things it is more likely to be the gasket than the head itself. It is possible for them to crack or go porous but most of the time it is the gasket. TD5s on the other hand like what I've got are vulnerable to faults in the head casting itself, but the 200 or 300 tdi ones seem much tougher.

Done the deal, bit the bullet and bought it. I will find out when i pull the head off if i've wasted my money.

Have you had a cooling system pressure test done? Worth doing if you think you've got exhaust gass in the water. If it holds pressure you're probably ok. Also be aware that new 200tdi heads are no longer available I am led to believe and you can only really skim them once

It's unlikely to be a duff head but if it is there are plenty around cheap enough