Radiator Leak - 2007 Pontiac G6

I have a 2007 Pontiac G6 (3.5L V6), and over the past year or so, I’ve noticed a slow leak in my radiator. I notice every 5,000 miles or so that my radiator reservoir tank reservoir is low, so I top off and monitor it regularly. My trusted mechanic informed me that if it’s a slow leak, it can likely be very difficult to identify the source, and to essentially monitor it until it gets worse.

This weekend, I’ve finally narrowed down the general location of the leak, which is in the front of the car on the passenger side, about 18 inches from the front of the bumper. I’ve done my best to inspect with flashlights and mirrors, but simply can’t see well enough through the engine to find the real source. I believe the drainage on the radiator is on the driver side, so don’t believe this is a simple plug issue, but don’t know if it’s worth spending the money to have my mechanic tear apart the undercarriage of my car trying to identify this. Any thoughts or suggestions would be greatly appreciated!

Have you gotten under it for a look?

I have, the metal frame, along with the plastic from the bumper make it impossible to see exactly where it’s coming from. I can see that it is pooling on the passenger side, but can’t see much more detail. My only option is to start to take off at least part of the front bumper, and even if I do, I’m still not sure how much I’ll be able to see since it’s such a slow leak.

I spoke to my Mechanic today, and recommended that he do a pressure test of the system which will cost a little over $50. I’m hesitant, because with such a slow leak, I’m afraid that it won’t reveal the problem, and I’ll be out $50 with no answers. Right now, that sounds like it may be my best option, but once again, am open to any suggestions. Does anyone have a suggestion of services to ask my Mechanic to perform to give him the best chance of finding the leak? I have a bad feeling that after the pressure test, I’ll be told that he can’t identify the source, and that the solution will be to replace the entire radiator.

If he puts a dye in the cooling system and then pressure tests the cooling system the leak can be located when the dye is detected with a UV light.


I will ask him about adding in a dye, I’m hoping this will identify the source. Would most of you agree that a slow leak like this poses little threat to the car itself? I’ve heard many people say this, but I just have an issue with something not functioning correctly, and simply ignoring it.

Is it still under warranty? If so, you might let the dealer take care of it. I think that this would be covered by the 3 year/36,000 mile part of it.

Unfortunately, it is not under warranty. The car has approximately 55,000 miles on it, so unless this falls under the 100k Powertrain warranty (which I don’t believe the cooling system does) I’m on my own.