Montero fan blows but no hot air (no defrost/vents)
#1
09-20-2012, 01:56 PM
Montero fan blows but no hot air (no defrost/vents)
I have a 1993 Montero SR (224,000 miles/runs great with no engine lights!) I just bought and don’t have any experience with these. The heater is not blowing hot hair at all. The dash temp gauge is saying it is warming up to normal (about mid-way) operating temp and does so quickly (within 5 minutes). It’s still fairly warm in Maryland so I’m unsure if the thermostat could be stuck open (thus the engine is still getting warm enough) or if it’s some other problem (like a bad control valve or lose/bad vacuum line or wire?). The dash air temperature **** seems firm with normal resistance so I don’t think the cable or **** is broken. The temperature does not change from one extreme of the **** to the other (blue to red).
Should I change the thermostat first or look/try something else? The water pump was changed about 2 years ago and the fluid looks clean and green…so I doubt the heater core is plugged up or the pump is the problem.
Two other things, the A/C is not working but has the belt on the compressor and seems to be okay. When I tinker with the controls for the A/C, it does not affect the heat problem at all. The seller said the A/C works but requires a seasonal charge because it leaks out over several months of Summer use. Seller also said the SUV used to eventually blow warm air after about 30 minutes, but I have not been able to reproduce that. Doesn’t that kind of sound like a thermostat was going bad and eventually just entirely croaked?
Thanks much!
Andrew
Should I change the thermostat first or look/try something else? The water pump was changed about 2 years ago and the fluid looks clean and green…so I doubt the heater core is plugged up or the pump is the problem.
Two other things, the A/C is not working but has the belt on the compressor and seems to be okay. When I tinker with the controls for the A/C, it does not affect the heat problem at all. The seller said the A/C works but requires a seasonal charge because it leaks out over several months of Summer use. Seller also said the SUV used to eventually blow warm air after about 30 minutes, but I have not been able to reproduce that. Doesn’t that kind of sound like a thermostat was going bad and eventually just entirely croaked?
Thanks much!
Andrew
#4
09-24-2012, 02:05 PM
Fan blows strong and vent selector changes air flow to the correct passages. Switches and heater controls feel and seem to operate fine. Vehicle does not overheat, and the interior temperature gauges indicates it warms up to operating temperature in just a couple of minutes. Since it warms up and the fan is blowing, doesn't this indicate the Thermostat is ok? Could the heater core be that clogged? Could the heater unit be turned off and I don't know it? If I'm to pull the heater hoses on the firewall side, how do I know which one is the return line (from heater core back to engine?) so I can check the flow through the core? Thanks!
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