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Radiator Leak

I keep losing coolant in my radiator but do not see any signs of a leak. (Water on ground, etc)

The coolant has to be going somewhere!

If you are sure that it is not leaking externally, then that leaves the likelihood of an internal leak, allowing the coolant to be burned in the cylinders (not good for the catalytic converter), into the motor oil (potentially disasterous for the engine), or into the transmission, via the trans cooler (potentially disasterous for the trans).

I would strongly suggest that you check your motor oil and your trans fluid for evidence of coolant contamination. This would be an appearance that could be described as “milky”, rather than the normal appearance of those fluids. If you do observe this, get the car to a mechanic for a compression test, a leak-down test, and any other tests that your mechanic deems necessary to determine if you have a head gasket leak or (more likely on your car) an intake gasket leak.

VDC’s post is excellent as usual. Checking those fluids in particular is critical, because if you have a headgasket problem it needs to be found and corrected pronto, as it can ruin the engine.

However you may want to start also with a pressure test of the system. And I have to ask, do you smell any sweet smell in the passenger cabin?

Thanks, I will have it checked out.
I did detect on odor on our recent trip to Atlanta, about a 3 hour ride but it was not constant and is gone now.

What year and what engine? While searching through some GM TSB’s I found a interesting one about unexplained coolant loss,let me know and I will check.

It is a 97 Cutlass, 6 cylinder.

Nope, it was for 2001-2006 4.8,5.3 V-8 coolant loss due to porosity in head casting #06-06-01-019a. I always check for TSB’s sometimes you get lucky.

Thanks, I’ll have it checked out.