Old timer told me to never trust a coolant flush machine

Guy named Mike at the shop I started at swore by just doing drain and fills by hand. Said the machines push crud loose and cause leaks. Laughed it off until I used a machine on a 2005 F-150 with 180k miles. Heater core blew out 3 days later. Customer was pissed. Ever had a machine cause more problems than it fixed?

2 comments

2 Comments

fiona_nelson511d ago

That machine can definitely be the culprit but in my experience it's more about reacting to what's already there... if that truck had 180k on the original coolant system, the crap was already plugging up the heater core anyway. The machine just flushed the loose stuff out and then the crud that was holding it together finally let go. Kinda like how a high mileage transmission flush can sometimes kill the thing, it's not the flush itself, it's what it reveals. I bet if you'd pulled the heater hoses and backflushed it by hand, you'd have seen the same gunk coming out...

grant_torres1d ago

@fiona_nelson51 nailed it.