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Old 24th March 2018, 04:28   #41
kaiser
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The thermostats I have come across have failed in the welding around the middle. Some fail from virtually new.
The pipes usually fail along the seams, and a few have been so rotten that they crumble.

That some failures occur around the O-ring, is obviously also the case, but to suggest this is the case every time you see coolant in the V is ..... not what I have found.
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Old 22nd October 2020, 16:30   #42
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A bit of a thread resurrection here!

Whilst answering another coolant query in the technical section (1.8 this time) I stumbled across this:

https://rimmerbros.com/Item--i-CDU3858OS

I don't know if it's been spotted or mentioned before, or if anybody has tried them, but it's another potential solution to the persistent o-ring failures seen on the KV6.

It depends just how oversized it is I suppose, but I feel this could be a solution for my problems and thought I'd share it just in case it helps anybody else.
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Old 22nd October 2020, 17:25   #43
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Rimmer have always listed this Part Number with the normal one for the KV6 thermostat assembly, but the details say it's For stainless steel pipes.

That suggests it refers to a different application, so somewhat confusing.


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I feel this could be a solution for my problems
What problems do you have?


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Old 22nd October 2020, 21:21   #44
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Quote:
Originally Posted by Randyjim View Post
I don't know if it's been spotted or mentioned before, or if anybody has tried them, but it's another potential solution to the persistent o-ring failures seen on the KV6.
Hello Jim,

I experimented with oversized 'O' rings but all I succeeded in doing was breaking the thermostat housing when trying to locate it into place.

Having exhausted all the possibilities I could think of I took up the suggestion of another club member. He asked if movement could be responsible and sure enough, I could easily rock the whole assembly by grasping the large thermostat hose. It was then that I discovered the purpose of the mysterious plastic clips on the straight pipe. Moving these fully outwards stopped the movement and, with new 'O' rings I've had no leakage since.

Simon
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Old 23rd October 2020, 11:46   #45
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I tried a slightly larger ‘O’ ring Gary (32.92 mm ID x 3.53 mm cross section) and my thermostat housing was written off when attempting to fit it. So I would not recommend that approach.

Simon
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Hello Jim,

I experimented with oversized 'O' rings but all I succeeded in doing was breaking the thermostat housing when trying to locate it into place.

Simon
So where these oversized o-rings CDU3858OS or something you sized up and ordered seperately?
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Old 23rd October 2020, 11:55   #46
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Quote:
Originally Posted by T-Cut View Post
Rimmer have always listed this Part Number with the normal one for the KV6 thermostat assembly, but the details say it's For stainless steel pipes.

That suggests it refers to a different application, so somewhat confusing.


What problems do you have?


TC
A little bit of digging suggests that some MGTFs use a stainless pipe set.

My problem appears to be a slight leak from the base of the banana pipe, where I suspect a scored bore in the block is the main reason. It's slight enough that 3 years later I'm still living with it quite happily. It only leaks in winter, and has improved significantly since I replace my header tank.
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Old 23rd October 2020, 13:39   #47
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Quote:
Originally Posted by Randyjim View Post
A little bit of digging suggests that some MGTFs use a stainless pipe set.
That might explain it I guess, thanks.

Quote:
My problem appears to be a slight leak from the base of the banana pipe, where I suspect a scored bore in the block is the main reason
The thicker o-ring might take that up, maybe not, but worth a shot. Use a good smear of silicone to lube the joint and I reckon it will push into the head OK.



Quote:
and has improved significantly since I replaced my header tank.
Can't imagine why.


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Old 23rd October 2020, 14:27   #48
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So where these oversized o-rings CDU3858OS or something you sized up and ordered seperately?
They were not Rimmer's CDU 3858OS. I selected mine from the range offered by a specialist 'O' ring supplier.

Simon
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