Nissan Frontier Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
I"ll try to make this short.

1999 V6 4X4

I've been having issue with poor heat output, getting air out vents around 90F (increases some when on the throttle). All the damper doors appear to be functioning properly as well as the blower motor

Things I have done
Replaced thermostat, tested old stat afterwards and it worked in boiling water.
Flushed heater core
Replaced engine temp sensor and temperature switch
Bled coolant several times. With bleed screw and also with a tall funnel.

My OBDI scanner tells me the coolant temp is running normal around 190-195F, however when i Probe around the engine compartment with an infrared thermometer the highest temp i am seeing is around 145F. This includes the upper radiator hose, bleed screw, rear of thermostat housing. The lower radiator hose is only reading around 65F. The heater hoses are warm one is around 145F and the other is around 120F.

Truck does not overheat and temp stays pretty steady in all conditions

No leaks anywhere

My water pump was replaced around 15K ago.

Could it be the radiator? Any other thoughts?
 

·
Registered
Joined
·
3,063 Posts
Is your fan clutch working properly at low temperatures, or is it "always locked up" ?
 

·
Registered
Joined
·
12 Posts
Discussion Starter #3
Not sure how to check that, please advise.

The radiator fan runs constantly but not real sure how the clutch part is supposed to work.
 

·
Registered
Joined
·
5,999 Posts
There is a heater control valve that is known to go bad on the titans. This is the valve that diverts coolant from the engine/radiator loop to the heater core. This sound like it could be your issue since you have checked everything else out. The easiest way I think you can troubleshoot this is to bypass the valve with a double ended barbed fitting and see if you get full heat. This is what it looks like on the Titan. Every nissan I have owned this valve sits in a same approximate location on the fire wall.
 

·
Registered
Joined
·
299 Posts
I have the same problem. It's an air pocket in the cooling system. Mine won't give ANY heat until I get moving over 2200 rpm. When I shut it off, I can hear air bubbles moving in the heater core. I'm having my coolant replaced soon, should take care of it. Check your over flow tank and see if there is any coolant in it. If not fill to the top and drive for a while (at least 30 min) and let it sit over night. Check in the morning and see if it sucks out the coolant. Keep it up until is stops eating coolant.

Or you can try this: https://youtu.be/REjYjiO8xIs
 
1 - 5 of 5 Posts
Top