Have a 99 DeVille and the "Check coolant" message appears every 5-10 days. Add coolant and again the message appears. There is no leak anywhere that I can find. Where could this stuff be going? Thanks for your help.

 

I had coolant leak on a Ford a few years ago, and I didn't seem to have a coolant leak either. It turned out that I had small crack in the heater control valve. When the car sat in the garage, there was no leak because the system wasn't running the coolant near the crack. I only found the leak after running the car a little while, then opening the hood to find the valve just a little wet. Essentially, the leak would only happen as I was driving, therefore all the drippage was happening on the road, and thus no coolant in the garage.

This is just what happened to me, so you might not find a huge leak, but something really small that you wouldn't actually see unless you felt around certain components. Just my guess.

 

Thanks for the info. I did run it for some time and did not notice any dampness. Another fellow thought the cap could be bad. So will check out your info and his also.

 

FOUND IT!!!
Would you believe it was the water pump? Took it to a dealer becuse it was a nightmare to put it on. They also installed a new thermostat total cost $289. Thought it a good deal. Thanks for all yur help.

 

I am having the same problem right now with my 94 caddy deville. I had an 89 and my waterpump on it was making all kinds of noise so that was an easy fix. But on this car I noticed a small greenish colored line going down by where the waterpump is and thought I bet its the water pump I am for sure now after seeing your post thanks