Major External Coolant Leak (only at operating temp)

2003 Pontiac Montana 3.4 L
225000 Kms
Intake Gasket replaced allready at 60,000 kms (yes a while ago) :)


Recently, noticed a major external coolant leak at the front of the motor (passenger side). It only leaks when at operating temperature and under pressure. It does not leak when you first start the engine, it takes a while before it leaks.

I replaced the rad cap, just in case it was faulty. Upon the second test, after getting it running good and hot, it leaked again. But only when at operating temp. It is not overheating.

Problem is, as the coolant is leaking out, the main drive belt is spashing the coolant all over the place and thus I am having a heck of a time pinpointing if it is a head gasket or intake manifold leak or perhaps somewhere else.

I can't take things apart to get a better view, because it needs to be running at operating temp to get the leak. If I pull anything apart for a better view, I won't be able to start the engine to reproduce the leak.

Any tricks or suggestions would be greatly appreciated.

tia
Zig

I would suggest buying/renting a pressure tester for the cooling system. This will let you pressurize the system without it running. Then inspect LIM and water pump. You can pull the belt off and remove the pump pully for closer inspection of the water pump weep hole. Good luck!

Mine did this on the right side (near firewall), it was a bad headgasket!

If the belt is throwing fluid, like Gmtech1 said, I would look at the w/p first.....

thanks everyone for your help and advise. I did borrow a pressure tester and it turned out to be the water pump.

Good News, changing the water pump on the Montana 3.4L was not to difficult

Zig