ronmexico

I've replaced:

-Upper rad Hose
-Lower Rad Hose
-Coolant Expansion tank
-Radiator

And my coolant leak has gotten beter but still persists.

My problem now is that the leak looks to be coming from the trans oil cooler?

There is a small pool of coolant collecting and dripping right on the clip where the unit connects to the radiator.

What I cant seem to figure out is if it's the trans oil cooler, or the thermostat.

I think I remmebr seeing that to remove the trans oil cooler I need a special tool to remove the hoses? Is this the case for the thermostat also?

I don't remember exactly how all of it was connected to the radiator. What I do know is it was a pain in the @$$ to remove the assembly from the radiator...

txag_530i

You didn't write what kind of car you have, but on my 2006 530i I was able to remove the transmission oil cooler thermostat without using special tools. Once you drain the coolant, remove the upper radiator hose (allows easier access) and the hoses to the thermostat. There are six Torx-head screws that hold the thermostat on to the carrier. You should by a new sealing set as well.

If it is necessary to actually replace the transmission oil cooler then a special tool is required for removing the oil lines to the cooler.