[feuer]

So the coolant plastic line mounted on the subrame broke. The T that goes into the ATF heat exchanger cracked. The engine didn’t over heat. However the ATF gushed out and I’m not certain exactly from where? I don’t think these two failures are coincidental. The ATF mostly sprayed on the left side, where the ATF heat exchanger is. I concluded this by the amount of ATF on the hood. Any ideas?

[Radu328i]

Maybe the 7521064 transmission oil coler thermostat is the guilty one. I don't even know if its hysteresis is high temp to lower or vice versa.

[feuer]

Originally Posted by Radu328i

Maybe the 7521064 transmission oil coler thermostat is the guilty one. I don't even know if its hysteresis is high temp to lower or vice versa.

I will replace the coolant line and then will the AT with ATF. If the heat exchanger is faulty or the lines I will replace them too. Just hoping the AT didn’t get damaged.

[feuer]

I have found the reason. The fan shroud wasn’t secured properly on the IC so the whole piece with the ATF heat exchanger was moving towards the engine while driving. The coolant line cracked because of the movement. We all know how brittle BMW plastic gets. The ATF heat exchanger got damaged by the bolts on the power power steering pulley.