Xantia 110 HDI - rear suspension

[Old-Guy]

When was the thermostat last changed? In my recent experience, they often don't last more than 3 years. Wax 'stats tend to fail gradually as wax leaks past the seal on the piston rod. This means that a failing 'stat operates at the correct temperature but doesn't open fully so the flow through the rad becomes progressively more inadequate as more wax escapes over time. Replacing a 'stat is a hundred times easier and cheaper than a blown HG. In fact, it's such an easy job (on an XUD) that it's no sweat to take one out and test it by putting it in a suitable receptacle and covering it with at least a pint of boiling water - it's obvious if it opens fully; anything less, chuck it as it will fail rapidly.

[Dom_81]

I apologize for letting this thread drop. The good news is that the new head gasket is holding; even in London traffic jams on hottest day of the year, the temperature remained stable.

The HG was done 3 times in total, 1st one failed immediately so mechanic had to pull the engine apart right way and re-do it. Then, the system developed a coolant leak causing levels to drop without me knowing and it went again, fortunately done again under warranty! 3rd time lucky it seems, i check coolant daily and leak seems to have stopped by itself.

Thanks for all the input, I have one final issue with the suspension so will create a separate thread for that