I have a 1999 F 150 that is having an overheating issue. the thermostat has been replaced and it has passed a compression test. It will run for about 15-20 minutes and then start to overheat again. If you leave it for about 6-8 hours you can start it up again and it’ll run for about another 45 minutes. What do we think the issue could be?
Clogged radiator, bad water pump, dirty AC condensor, bad fan clutch… Far too many possibilities to narrow down given the tiny amount of information you’ve shared. Share more, much more, engine, transmission type, miles, , and we’ll try and help.
Also… compression test? You mean the one where the spark plugs are out and a gauge is attached? Or pressure test of the cooling system?