KV6 lower inlet manifold gaskets.

[Typhoon190]

Originally Posted by zefrench

I was hearing that rubber flattens when exposed to more heat than it can deal with.

Could it be that the material of the o-ring of the thermostat is not tolerant of the temperatures it is subjected to there ?

I ask because all the reports I have seen have been the orings that are at "the bottom" and not one that is either end of the straight pipe that goes into the water pump flatten.

Is there such a thing a material with greater temperature tolerance ?

Anyone know or ever looked at this ?

http://www.viconerubber.com/en/materials/

It's trying to find a rubber that's suitable for the temperature range, and is also not going to be eaten by the OAT.

[SD1too]

Originally Posted by zefrench

.. the reports I have seen have been the o rings that are at "the bottom" and not one that is either end of the straight pipe that goes into the water pump flatten.

Agreed, and certainly true of my engine.

Is there such a thing a material with greater temperature tolerance ?

Yes, EPDM can withstand 150°C.

Anyone know or ever looked at this ?

Last time around I fitted EPDM 'O' rings. I currently have a leak into the 'V', just the same as if the MGR 'O' ring is fitted.

Originally Posted by Typhoon190

It's trying to find a rubber that's suitable for the temperature range, and is also not going to be eaten by the OAT.

Ben; you've made two assumptions there. There are plenty of KV6s around using OAT and with normal coolant temperatures which do not suffer 'O' ring failure. These cars have standard MGR 'O' rings and plastic hardware. So it cannot be the material or the temperature or the OAT.

However, I have to admit to being a naughty boy. I haven't been renewing my OAT solution at the prescribed five year interval. Perhaps the inhibitors degrade and become corrosive after this time. I don't know, but maybe T-Cut does. I will shortly renew my 'O' rings again, and I will also renew the OAT solution and we'll see what happens.

Simon

[zefrench]

Originally Posted by SD1too

Agreed, and certainly true of my engine.



Yes, EPDM can withstand 150°C.



Last time around I fitted EPDM 'O' rings. I currently have a leak into the 'V', just the same as if the MGR 'O' ring is fitted.



Ben; you've made two assumptions there. There are plenty of KV6s around using OAT and with normal coolant temperatures which do not suffer 'O' ring failure. These cars have standard MGR 'O' rings and plastic hardware. So it cannot be the material or the temperature or the OAT.



However, I have to admit to being a naughty boy. I haven't been renewing my OAT solution at the prescribed five year interval. Perhaps the inhibitors degrade and become corrosive after this time. I don't know, but maybe T-Cut does. I will shortly renew my 'O' rings again, and I will also renew the OAT solution and we'll see what happens.



Simon

Thanks for taking the time to tell us. I look forward to hearing if the EPDM o-rings were flatten just as much as the regular ones.

[Ivan]

i am having exactly the same problem of leaking inlet manifold gaskets

i have been considering giving the new gaskets i have just ordered from rimmerbro's a thing coat (and allow it to dry) of silicone sealant before i install them, just to try and water proof the paper some what.

[kaiser]

While that might help, I think the main problem is the permeability of the paper itself.
If the water gets under the seal anywhere, it is drawn through the paper as were it blotting paper.
I tried to cover with red silicone compound at one stage, and it did not work.
Far better to coat with some substance that blocks the paper by penetrating into the pores all over.
My effort with silver paint spray from an aerosol (both sides) seems to have worked.

[mungo76]

Recently purchased new inlet manifold gaskets from a supplier in Jo'burg that came from Britpart, they actually have a special sealant (looks like a silicone layer) on one side that might help to prevent the coolant being penetrating in to the paper, when the gasket is placed in the right manner. I predominantly suspect the coolant being the culprit here sachurating the paper and causing the gasket to get weak and causing leakages. I also have the problem with coolant leaking, creating mayo in the 9mm breather pipe, at the oil filler cap and at the camshaft cover oil separator (filter guase)

[kaiser]

Welcome to the club. Typical South African! jump straight in, worry about sharks later.
Benoni, far east! One liter Rum, two liter Coke and 2.5 liter Rover!

Hope you enjoy your stay here!

[mungo76]

Thanks for the warm welcome Kaiser.

Yup you are not far off regarding your comment about the far East hahaha.
I yet have to figure out who is more thirsty, me with in total 3 litres or the 2.5 liter Rover.

Will surely enjoy my stay here thanks.

I thought it was time for me to start sharing my experience/ built up knowledge working on my Rover 75 over the past few years , it might help others on the group, as it helped me reading posts of others in the past.