Thermostats housing keep Cracking

[Abdo8104]

Hi,
I own a 2001 peugeot 406 hdi diesel. The only problem I had for many times is the thermostat housing. It keep cracking, and it mix the water with diesel. So I have to keep adding the coolant.
Does anyone had this problem? If so, what cause the problem? ( the problem is that thermostat housing cracks all time)
I attached a picture of the part that keep failing.
Thanks in advance.

[PeterN]

I don't remember seeing anything like that on my 406 diesels, looks like a much more modern arrangement.

Peter

[steve_earwig]

They have something like that, I think earlier were aloominum later were plastic. Never heard of one breaking though

[dirtydirtydiesel]

Yeah, that's the same part I had an issue with removing when I did my head rebuild.
It's buried under the intake pipes ect on the end of the head above the gearbox.

My advice would be to use a genuine Peugeot one or find out who supplies Peugeot
I've never had an issue with mine cracking but it's oe.
The one in the picture looks very brittle plastic.

[WillNZ]

where exactly is it cracking? Have all of them cracked in the same place?

I have owned a lot of these hdi's and never had an issue with any of them cracking. Only had to replace the thermostat itself on several of them.

Are you perhaps overtightening the holding down bolts? Or is the mating surface on the head uneven?