I had my heads replaced on my 99 malibu about 5 months ago. The fans wont start when i turn the car on. I have ot turn the ac on for them to turn on. Its now overheating and makin a noise. There is no water in the oil. WHat could be the problem?
Fan should not be on 'till the engine goes slightly over operating temp. if they fail to come on at all, check the temp sending unit (should be near the thermostat housing) Sender sends signal to computer, computer sends signal to fan relay, relay turns fan on. to check fan itself, hot wire it to the battery (but if both run with A/C don't bother.) Only way to find a leak is by looking carefully everywhere in/under the engine compartment. Other overheat causes are: bad thermostat, water instead of antifreeze and internal or external obstruction of radiator. Don't know if heads were tested for cracks and warpage but that can cause a problem if they weren't. Other tests are: hydrocarbon test at radiator, cylinder leakdown test, pressure test of system and dye test for leaks. I can't tell you what your problem is but these are the things I'd need to do to find it.
good luck
Change your temp sensor if there is one bc i believe like my car it regulates fan function when hot. Also see if you got enough oil (trust me) and burp the hell out of the coolant system. Then see is you relays for the fans are good. Basically switch them with equal relays but dont switch with primary system relays also check your fuses that may help
186 views
Usually answered in minutes!
the engine cooling fans don't run until the engine coolant temp reaches about 225-230 degrees f. or when the AC line pressure is over 175PSI
×