Just lost a full day to a coolant leak on a 2015 F-150

Had a truck come in with a slow drip. Pressure test showed nothing, dye test showed nothing. Finally found the leak was from the thermostat housing, but the plastic had a hairline crack you could only see with a mirror and a bright light from underneath. What should have been a one hour job turned into eight hours of hunting. Anyone got a better method for finding those hidden plastic leaks?

4 comments

4 Comments

reese_rodriguez864mo ago

Those phantom plastic leaks are the worst. It feels less like fixing a truck and more like a really boring magic trick where the leak disappears the second you look at it. Glad you finally tracked it down.

grant4783mo ago

Hate those sneaky plastic leaks. They hide until the system gets hot and pressurized. Sometimes you just have to let the truck get to temp and start feeling around.

marydavis4mo ago

My neighbor's 2007 Civic had a mystery puddle for three months. We replaced the radiator cap, the hoses, the water pump. Turned out to be a tiny split in the overflow tank neck that only opened up when the engine was hot and the fan kicked on. Sometimes you just have to get lucky.

brianm6629d ago

Three months is about how long it took my buddy to find a leak in his Camry that only showed up when the car was parked facing uphill on a hot day. That overflow tank neck trick is brutal since it seals itself shut once the pressure drops and you start poking around with a cold engine. Might be worth checking if the leak happens on an incline next time before you start replacing parts that were fine.