Truck was running too hot last week. Not overheating just running to the high end of the normal range. Went to add coolant and added over 1.5 gallons of coolant and water.

Took the truck out and ran it for about 30 minutes and it ran in the lower half of the normal range. Went out the next morning and there was a substantial puddle of coolant under the truck. Not all that I added, but a fair amount. I figured I overfilled it and went on. Drove the truck to work Sunday and Monday and ran cool. This morning when I got to work I notice the smell of coolant and more was dripping out just behind the front suspension left a decent puddle. Truck is running warmer on the way home.

Any suggetstions as to why I'm losing coolant?

 

check the hoses first, snug up the clamps. make sure you check the heater hoses where they go to the fire wall. these are common for leaking. make sure the radiator cap is on tight, if not or if its bad, the system will not hold pressure and you will loose coolant throught the overflow bottle.
it will be best if you can pin point the leak. when cold move things around and see if you find the leak. if not do it when its warm. where abouts is the puddle on the ground?
what year truck and engine?EDIT i just saw the sig

 

If your filling the overflow tank, bad cap.

 

It's probably time for a new water pump. Crawl underneath the front of the truck, and look up at the water pump. There is a hole in the pump body just below the shaft that acts as a weep hole when the pump starts to fail. If it's wet, or has stains from fluid, replace the pump. When you do, buy new bolts along with the pump. Trust me on this one.

Also, don't add so much coolant. a 50/50 mixture is too much coolant.

 

Actually, the overflow bottle never has anything in it. The puddle I can see it dripping behind the front suspension.

 

If this is your 88 then I will assume you mean left of the engine as you look at it from the front. All of the cooling accessories are over there if memeory serves me. After checking the heater hoses and heater core (the passenger side floor is not damp is it?) I would look to the hose on the overflow and the overflow itself. It can run right down the inner fender and come out behind the front suspension. I also would check the waterpump weep hole. Use a mirror held underneath it and it will be pretty easy to see. Definitely check all the heater hoses as the run right around the passenger side inner fender. Look for trails where the water might be running. Sometimes a leak on the front of the engine in the right place can run all the way to the back before it drips off .

Hope that helps

 

if you can borrow a radiator pressure tester from autozone or somewhere then hook it up and pump it up to 16 PSI and then crawl around the engine till you find the leak.