Quote:
Originally Posted by Randyjim
I thought I was doing well with the viton O-ring and molykote 111 combo, they seem to have lasted about 9 months this time ...
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Hi Jim,
Like you I have had repeated ‘O’ ring failures after varying lengths of time but after a great deal of experimentation and analysis I think I may have found the answer: prevent movement.
Renew all four ‘O’ rings. It doesn’t matter whether you use Viton or MGR original parts. A lubricant of some kind is helpful to assist correct seating when the plastic parts are refitted. The key lies with the clips on the straight pipe. I spent a lot of time pondering over the purpose of these but I think I’ve worked it out. Ensure that both clips are pushed fully outwards so that each is in close contact with the water pump shrouding and the thermostat housing. This forms a rigid assembly without which it is possible for the thermostat housing to rock slightly. My theory is that it is this movement which is flattening the ‘O’ rings, introducing a leak which sprays upwards over the thermostat housing seam causing the innocent owner to be convinced that the plastic has split. It hasn’t.
In order to carry out this repair reliably and efficiently I recommend not using the keyhole method. It is also good practice to observe the torque setting of 18 Nm for the bolt securing the curved pipe and thermostat housing to the block.
Simon