[jack mccarthy]

If you have clear red tranny fluid I wouldn't be concerned. Any coolant in the tranny will form an emulsion with the tranny fluid (milkshake) and be totally obvious. However, a $25 fluid analysis is cheap insurance.

How old is your water pump? A slow coolant leak will most likely be either a leak at the water pump gasket or at the bearing (weep hole), a seeping radiator or a leak at one of the two water pump o-rings.

I had the water pump, thermostat, serpentine and timing belt done at 100K and I'm at 74.5K additional miles. Didn't see any seepage around the water pump but maybe when I change out the radiator it'll be more apparent. The dealership used RTV gasket sealant instead of the standard water pump gasket.

 

[shatto]

Many garages and all radiator shops can pressure test your system, often for free.

 

[kovawa]

Many garages and all radiator shops can pressure test your system, often for free.

Other than adding tracer dye, a pressure test will yield the best results. Maintaining pressure on a cold cooling system overnight will most likely indicate the source of your leak. I've had to resort to an "overnight pressure test" on many occasions, when I worked as a tech. Often, it's the only sure fire way to find the problem.

 

[shatto]

That outta put pressure on him to get the problem fixed. ....