Hi all,
I finally changed my thermostat, as my engine didn't warm up correctly... I tested the old thermostat, and found that even if it opened in boiling water, it didn't close fully when cooling ! It was seized...
By the way, it's a mess to take out the thermostat housing on the 5.0, and an even bigger mess to put the lower bolt back, as the water pump casting fouls its screwing ! Little trick : i eventually used a saw to make a slot in the bolt head,in order to use a screwdriver passing through belts to make the bolt finding its path...
It's far better now, even though my fan still cuts in too early ...
But now a new wonder arises : i had a look at the expansion tank, to find out that it is only connected to the upper radiator pipe, AFTER the pressure cap ... It means that it only collects overflow water, when pressure cap has opened, and that there is no way to make this water go back to the circuit when it get colder ! I understand now why the level was always the same, cold or hot !
It is by the way more an overflow tank than an expansion tank ... I assume other MKIVs have the same configuration? So how to know that the coolant level is ok , as the level on the tank is irrelevant ?
I think i'll make a derivation in one of the water pipe that goes to the butterfly or to the heater, to make a "true" expansion tank... has anyone already done this ? I've read in Sept '12 ACtion that Nick Godridge modified his coolant system, IIRC...
Thanks !
Olivier