Have you check for leaks with engine on or off? It's better to check with engine on, or with cooling system under pressure because small/slow leaks become more apparent.
Pressure check your cooling system. Pay special attention to your intake manifold; GM 3.4L engines are known for leaky intake manifold gasket.
I would also suggest you have your radiator cap pressure tested. If the cap doesn't hold the pressure, some coolant will come out. Actually, a new cap costs around $5 so simply replacing it may be the better option.
If you can't find any external leak, you may have an internal one. Your engine may be burning coolant (usually when this happens you can see white smoke coming out of your tail pipe), or some coolant is finding its way to your oil (check your oil fill cap: does it have a gray-ish gooey substance in it? Also check the level on your oil dipstick for higher than normal level and discolored oil). An internal leak will require expensive repair.
It's also possible that some coolant is leaking into your transmission cooler/lines inside the radiator (check coolant for brown/red-ish spots). A new radiator is the only fix in this case.
Wednesday, December 2nd, 2009 AT 4:17 PM