CitroJim wrote:Yes, use ONLY Forte Stop leak!
Paul, it was your old V6 that was full of rad sealant that clogged the transmission cooler. It may have contributed to the failure of the gearbox...
In the long distance post mortem of my old Silver Xantia V6 (RIP) I came to the conclusion that the gearbox had been overheating for a long time (since before I bought it in fact) probably also due to a clogged heat exchanger, and that it very likely contributed to the gearbox failure!
I was not able to to inspect inside the heat exchanger, however I have records of gearbox oil temperature measurements taken by the Lexia under various driving conditions in both that car and the V6 I have now - the difference is night and day. Average oil temperature on the new V6 (with presumably a good heat exchanger) is about
15 degrees lower than the one I believed was blocked, and more importantly after heavy acceleration the new one cools back down to coolant temperature very very quickly (good heat transfer) whereas the other one not only got 15 degrees hotter in the first place but also stayed much hotter than the coolant temperature during prolonged periods of light cruise when the heat exchanger should have taken away the excess heat.
Designing a coolant expansion chamber that has a propensity to split its sides every 20K could well have been the death knell of many a Xantia V6 - the temptation to put some kind of radweld in the coolant instead of replace yet another flawed expansion chamber was probably too much for many people, with the consequences not coming home to roost until months or even years later. (Mine struggled on for a couple of years although I did have to change the oil a lot more frequently as it was going black unusually quick)
