My uncle told me to never trust a 'quick fix' on a coolant leak

He was a mechanic for over forty years in Detroit, and he always said if you see a stop-leak bottle in the system, plan on doing a full flush and finding the real problem. I brushed it off when a customer came in with a small leak and a bottle of that stuff already in there. I topped it up and sent them on their way. Sure enough, they were back two weeks later with the heater core completely clogged. The stop-leak had sealed the tiny leak but then traveled and gummed up the whole small passageway. It turned a fifty dollar hose job into a six hundred dollar dash pull. Now I check for it on every used car that comes in. Has anyone else had a simple additive cause a much bigger headache down the line?

2 comments

2 Comments

mason7286d ago

Ever wonder if those sealants can mess with the coolant temp sensor? I had a car running lean because the gunk coated the sensor, making the computer think the engine was always cold. Spent a week chasing ghosts before we found the real problem.

noah8806d ago

Yeah chasing ghosts for a week sounds rough. Was it one of those stop-leak bottles or did it come from a previous repair with too much gasket maker? Trying to picture how much gunk it takes to actually insulate the sensor tip.