I have a 1997 Ford Ranger with about 158k miles. I’ve been noticing the coolant level in the reservoir is leaking out about every 2-3 months. I never find a spot in the drive or smell anything. I checked the radiator and it is full and the truck has never overheated. About a month ago the temp was down in the teens and 20’s and when I would turn the heat on high, the truck would “click” and idle down to where I thought it may quit. I replaced the battery and checked the starter & alternator and everything came back fine. I had the radiator, condenser, water pump and timing belt all replaced about 3 years ago.

My questions are:

1) Are the two issues possibly related?
2) I’ve read where it could be something as simple as the thermostat which I could replace. Could that be causing both issues?
3) I’ve read where it could be a bad condenser. Does this seem to be more likely the problem?
4) I have a guy who has offered to do an A/C check by running the dye for $80 and topping it off. He said if that didn’t turn up anything he’d check the radiator for me. Should I take it to him or replace the t-stat and give it a week to see how it does and then take it to him if the problem persists?

I’m just struggling because I don’t want to pay out a ton of money if I can fix both issues with something as easy as changing the t-stat. But, I don’t know if there’s even a chance it could fix both. I guess I just need to know which direction to head first.

Any help or guidance would be GREATLY appreciated.

 

You stated "turn the heat on high". What do you mean, turned floor or vent of high heat? Or did you hit the defrost on high? When you use defrost, most of our vehicles will engage the A/C compressor to dry the air. IE clunk and idle down. If this is excessive it my point to an issue with the A/C system. The A/C system will not effect coolant levels. You may want to have coolant system pressure checked for leaks. How much coolant are you losing? Have you checked your hoses for wear and age, allowing a very small amount of coolant escape when hot or shut of cooling in the driveway?