Rubbish plastic thermostats
 

This time it lasted eight months and has now started to leak again. I really can't believe this as I was so careful when I rebuilt the engine. I must say I have nearly had enough of this. I suppose with hindsight I should have fitted Kaisers Metal thermostat but these are now no longer in stock. Does anyone have one available as I am prepared to give it one last try and that is going to be that.

Mr Toad

With what little holds them together I'm surprised that they all don't leak.
My Freelander ( rip) same engine had a thermostat leak and I just put radweld in and that was it .
Never leaked again 4 years before we got shut and never leaked

Many of the originals are still OK after 20 or so years. What does that tell you?:shrug:

That's all very well but there are many instances of failed thermostats. They are inherently unreliable.

Mr Toad

Hi Martin,

No, you don't need to fit Kaiser's metal thermostat. The leakage isn't anything to do with the material of which the thermostat housing is manufactured, it's due to the 'O' ring seals flattening. This happens because the whole assembly can move unless the serrated clips on the straight pipe are set correctly. That's their purpose! They should be moved fully outwards so that they're in intimate contact with the water pump and thermostat housings. I've had mine like this for nearly three years and no more leaks! :D
What do you mean by "failed" Martin? If you mean leaking then yes, you're right. But now we know why this happens, the simple procedure described above will increase reliability at a stroke! The problem seems to be that, despite me repeating the advice frequently, a lot of members seem not to be seeing it. :cry:

Simon

Hi Simon,

We went through all this last year when I replaced the head gaskets. When I refitted the thermostat pipes and seals they were all fitted precisely as you suggested but in any case if the seals have failed after only eleven months that doesn't say a lot. I haven't taken the engine apart yet but I wouldn't mind betting the thermostat has failed. I must say I am getting rather bored with this an unreliable car is no good to me. It's going to get one last chance and if that doesn't work straight to the Knackers yard!!


Martin

Hello Martin,

Just so that I understand properly, are you saying that you renewed all the CDU3858 seals (with genuine parts) and moved the serrated clips on the straight pipe fully outwards and now, after eleven months, you have coolant leaking into the 'V' around the thermostat housing?

Simon

Hi Simon,


Yes that is exactly the situation.

Regards,

Martin

That's puzzling. I'd like to find out why you have had the opposite experience to me.

1. Were you supplied with a thermostat housing modified with the two supporting legs?
2. Were the parts genuine MG Rover, aftermarket or just something from eBay?
3. Did you use the "keyhole" method?

Thanks Martin.

Simon

Martin, thank you for posting your findings in regards to the thermostat.

I would suggest that you indeed fit a Kaiser metal thermostat housing, this component takes away all of the worry and stress of a poorly designed original component leaking at random.

There will be people who erroneously insist the problem is caused by abrasion of particular components leading to leakage, but you have demonstrated perfectly in the case of your own car, that this simply is not correct.

Kaiser can be contacted HERE

Brian :D