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Thermostats housing keep Cracking

Posted: Mon Dec 14, 2020 2:40 pm
by 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.

Re: Thermostats housing keep Cracking

Posted: Wed Dec 16, 2020 11:43 am
by PeterN
I don't remember seeing anything like that on my 406 diesels, looks like a much more modern arrangement.

Peter

Re: Thermostats housing keep Cracking

Posted: Wed Dec 16, 2020 2:49 pm
by steve_earwig
They have something like that, I think earlier were aloominum later were plastic. Never heard of one breaking though :?

Re: Thermostats housing keep Cracking

Posted: Wed Dec 16, 2020 5:40 pm
by 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.

Re: Thermostats housing keep Cracking

Posted: Thu Dec 17, 2020 4:12 am
by 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?