Well I replaced the heater core 2 weeks ago using all the great help from this forum. I thought the problem was solved. Now I find coolant starting to leak AGAIN on the passenger floormat. I suspect there is a bigger problem. The new heater core is from NAPA, brand new. The cooling system was flushed in July at Jiffy Lube. Coolant was clean and green with very little sediment. The car is not overheating. With the new heater core, the mechanical temp gauge tracks exactly to the thermostat temp. One other clue: After driving the car for a few miles, then stopping the engine, there is a strange gurgling/bubbling sound from the cooling system. This sound was evident before installing the new heater core. For those diagnosticians out there, what tests should I do next, and what root causes should I be looking for? Thanks.
Can you see where it's coming from? Does you car have A/C? If not have a good look up where the hoses clamp to the core, did you use new clamps? Did they get over tightened? maybe too loose? Did you replace the heater hoses? Did you check the heater core before installing it? the new heater core could be leaking. Maybe find someone with a coolant system pressure tester and see if it holds pressure.
i had the same problem. my thing was the heater hose clamps needed replacement along with the new heater core(the old hose clamps didn't tighten as good as the new ones)
Pinhole in hoses to heater core Over/under tightened clamps New core leaks (seen it, been there done that) As for the gurgeling sound Coolant boiling due to loose/faulty cap or other overheating problem. Most likely cause...air trapped in cooling system.
Yup...I drill a 1/8th" hole in every T-stat I install(unless it allready has a small bleeder poppett on it)Apps for cars that are problem children to burp will usually have this on the new T-stat from the manufacturer. good call Frank
I put a new heater core in my 86 Bronco and it leaked. Took it back for an exchange, checked it out real good and I'll be danged if it doesn't leak. I have not gotten my nerve back up to replace it yet but I am going to have to real soon. New sure does not mean much anymore that is for sure. As far as the noises, park the car with the nose pointing up hill, take off the rad. cap and let it idle a while keeping an eye on the temp gauge. Sometimes this helps getting the air out of the system. I always had a hard time getting all of the air out of the newer 5.0's in the F150's when I rebuilt the engines. I always drill the hole in the thermostat as well. clint
i like to put one of the flushing tees in to the heater hose near the fire wall. when i fill the radiator i leave the cap off the tee. this lets the air escape out of the block and not get traped in the heater core. keep a eye on it and you will see when its full in the tee. then cap it off and top off the radiator.
