stevegroom

I had the original heater core on my 98 f150 replaced about a year ago. Several months later, I began smelling antifreeze in the cab and had a small leak on to the floorboard. I took the truck back and the shop replaced the heater core under warranty and said it had failed. They said they had used a Ford heater core and it was unusual for them to fail. Soon after I began smelling antifreeze again. No sign yet of a leak in the floorboard or a mist coming up out of the window defrost. Any chance it could be something in how the core was replaced that I can check/fix? I have moved and the shop is 2 hrs away, plus they would have to keep it a day to take out the dash again if it is the core.

Trapper

This is going to sound strange but believe me, you need to do this. With the radiator cap loose to relieve pressure, bring the engine up to full operational temp. Take a volt meter, digital is prefered, now put the negative end on the negative post of the battery. Put the positive side of the voltmeter into the coolant. How much voltage do you have? If you have over .3 volts, you are having a corrosion issue with stray voltage. Hopefully you haven't stuck some crap in the radiator like water wetter or some other heat reducing additive. If so, look for a buyer for yer now permanently screwed up engine and cooling system. If you didn't, you'll need to do a complete flush of the system using an acid based cleaner. You'll probably need to do it twice to get the voltage down. Make sure to follow up with a base to neutralize the acid flush. If you fail to get the voltage down, expect the radiator to be next, and then freeze plugs, then water pump, then hose connectors.......

Good old Bill

Am wondering with no presence of mist or external leakage if the foam material inside of plenium isn't saturated with coolant, residual from prior two leakages.