sorry to be the bearer of bad new but your heads more than likely cracked. if its a later euro 3 engine the castings were thinner.
I thought it was the earlier TD5s that had the problems with the heads, and the later ones were improved to try and stop the head from cracking,(although some still do)
Mark
That IIRC is correct. Which is one of the reasons I have a later 16p engined 03 D2