Coolant leak?

DAMIEN AUGUST

MEMBER
2004 PONTIAC GRAND AM
3.4L
6 CYL
2WD
AUTOMATIC
273,873 MILES

I have just picked up the car listed above (GT model) and noticed I have got coolant leaking like a sieve from behind the pulleys. The car itself runs strong and does not go over say 95 degrees Celsius which is half way on the gauge. I have kept an eye on oil it is all good. Just did oil change and it is looking just fine. I have not pressure tested the system because well I really am not sure how to do this, lol. I have got it on stands in the front end as we speak and passenger tire off and can see water pouring out of it steady but cannot locate the leak itself without having to rip the belt off and taking dressings off. Can anybody maybe shine a little light on this situation for me? Please and thanks. I appreciate all your time and if I ever come face to face with any of you mechanics on here all I can say is "I am buying"! Lol

3 Replies

STEVE W.

MECHANIC
12,967 POSTS

Most likely it is the water pump. They are not real hard to change. Start the cooling system draining. While that is happening, loosen the pulley bolts, then remove the belt. That way you do not have to fight the bolts as much. With the belt out of the way you can remove the pulley and remove the pump. Clean off any sealer and apply the new sealer. Bolt the new pump in and reverse the removal process. While you have the belt loose inspect it and the tension-er.

This guide can help us find it

https://www.2carpros.com/articles/car-is-leaking-coolant

Next would be the thermostat housing, it is right above the center of the engine. The gasket can fail and they will leak down the face of the engine. I have also seen the ears on the bottom fail where the bolt holds them on and leak because of that. The biggest issue with them is you have to remove the exhaust crossover to get to the housing. If the car is rusted that can be difficult. To make that easier you can get a couple candles, run the engine so the exhaust is warm and then rub the candles on the bolt threads on the crossover flanges so it can wick into the threads. It will work as a lubricant and help in removal.

Pressure testing is not hard, you can usually get the tool as a loaner tool from a parts store. Then let the engine cool off. Fill it full of coolant and pump it up to 15 psi. and look for the leak. Many will leak long before getting up to pressure.

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