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2008 Pontiac G6 - Coolant leak

There is a coolant leak somewhere. I have to add coolant once a week. I add close to half a jug of premixed fluid at a time. There is fluid on the ground after it sets for a while. I took it to three different shops and they can’t find anything. One changed the reservoir, but that didn’t help. One suggested it could be a head gasket, but wasn’t sure. I don’t want to spend $400 dollars on a guess. Is there any way for a mechanic to know for sure where the leak is coming from?

Yes, they can put dye in antifreeze and do a pressure test for external leaks and a an exhaust gas sniffer for a head leak. There’s also bubble and pressure tests for head leaks. But if it’s on the ground it is an external leak and should be easy to locate.

Thank you for the information. Now I know what to ask if I am told they can’t find anything.

You take it to a shop where they can pressurize the cooling system when it’s cold with this tool.

A leak that big should be pretty evident.


Agree with others that if it leaks enough to leave a puddle, it shouldn’t be that difficult (especially for a shop) to find.

Check also the coolant crossover gasket.

When it is parked at home and you find a coolant puddle underneath, open the hood and get a piece of string and tie a nut or something to one end. Then from the top of the engine compartment, locate the puddle and hang the string so that the nut or whatever is directly over the puddle, or as close to it as you can get.

Mark or note the location so you can find it when you take it to the mechanic. Hang the string in the same location so that the mechanic will know where to look for the leak. He (she) should be able to find it quickly. If not, you need another mechanic.

How does a mechanic do that?

I will give it a try.