HVAC Heating problem (1 Viewer)

[cruisin4bruisins]

Hello all, I have a 2002 Land cruiser with a heating problem. The AC blows really cold but my heating is intermittent. Sometimes its really hot but most of the time its just barely warm. Coolant is always full, no leaks. Does anyone have any suggestions?
Thanks
Lee

 

[cruisin4bruisins]

Also, would a bad HVAC blend door actuator be the cause for this? Thats all I can really find from researching online.

 

[2001LC]

Hello all, I have a 2002 Land cruiser with a heating problem. The AC blows really cold but my heating is intermittent. Sometimes its really hot but most of the time its just barely warm. Coolant is always full, no leaks. Does anyone have any suggestions?
Thanks
Lee

First: Check engine coolant temp (ECT) using tech stream.

Next: If coolant just a little low, you may still see ECT normal range. So check coolant level in radiator, not just reservoir. Before starting engine in the morning. After 8 hour cool down, before sun comes up, with front high than rear of truck. Remove the cap from radiator. Coolant should be to the top. Make sure reservoir is well above low line, and its hose goes straight to bottom and free of obstruction. OEM thermostat must be installed with jiggle valve up, and in good working order. Cap needs to also be in proper working order.


If HVAC only seems to work, while in auto, when temp set to full cold or hot. The air sample sensor or it's hose may need servicing. This sensor is behinds the tiny vent slits, about 6" under the key (IG SW).

Blender door would be next to check! A clue this issue, is rear heat blows hot, front does not. But coolant level a little low, may act the same (rear blow hot, front not)

 

[cruisin4bruisins]

First: Check engine coolant temp (ECT) using tech stream.

Next: If coolant just a little low, you may still see ECT normal range. So check coolant level in radiator, not just reservoir. Before starting engine in the morning. After 8 hour cool down, before sun comes up, with front high than rear of truck. Remove the cap from radiator. Coolant should be to the top. Make sure reservoir is well above low line, and its hose goes straight to bottom and free of obstruction. OEM thermostat must be installed with jiggle valve up, and in good working order. Cap needs to also be in proper working order.


If HVAC only seems to work, while in auto, when temp set to full cold or hot. The air sample sensor or it's hose may need servicing. This sensor is behinds the tiny vent slits, about 6" under the key (IG SW).

Blender door would be next to check! A clue this issue, is rear heat blows hot, front does not. But coolant level a little low, may act the same (rear blow hot, front not)

Thanks for replying! I don't have a way to see the temp of the coolant but the dashboard gauge always reads right in the middle when its warmed up. Believe me I have done everything to move the coolant around and its still at the very top, it seems to be full. I did have the timing belt and everything that comes with it replaced a month ago but I've had this heating problem since December of last year so I know the thermostat is good and the car runs great.

I think I'll investigate the air sample sensor next unless there's something else I can look into. Again thanks I appreciate it.

 

[Live to Ski]

Would a OBD2 dongle w. Torque pro give a good coolant temp for this diagnosis?

Cheaper and way less effort than techstream, it seems.

 

[cruisin4bruisins]

Would a OBD2 dongle w. Torque pro give a good coolant temp for this diagnosis?

Cheaper and way less effort than techstream, it seems.

Good question, I've used OBD2 dongles before and they never really gave me a lot of info. I dont think I would see ECT with that but I could be wrong.

 

[Kamran Khan]

Good question, I've used OBD2 dongles before and they never really gave me a lot of info. I dont think I would see ECT with that but I could be wrong.

Most of the times when heater isn’t working properly, it is due to air pockets in the radiator. Burping radiator will solve the problem.
But you said your problem is intermittent that could be due to faulty climate control. Or the actuator that is close to firewall that doesn’t open or close properly.
Check your heater T pipe, make sure those plastic pipe aren’t clogged or broken. Tiny chars of heater T pipe can get into heater HVAC hose and can cause blockage.
Few months ago, I replaced a good looking non leaking T pipe and upon inspection I found that the T was close to fail because some of the tiny particles of plastic from the heater T were about clog heater core.

 

[cruisin4bruisins]

Most of the times when heater isn’t working properly, it is due to air pockets in the radiator. Burping radiator will solve the problem.
But you said your problem is intermittent that could be due to faulty climate control. Or the actuator that is close to firewall that doesn’t open or close properly.
Check your heater T pipe, make sure those plastic pipe aren’t clogged or broken. Tiny chars of heater T pipe can get into heater HVAC hose and can cause blockage.
Few months ago, I replaced a good looking non leaking T pipe and upon inspection I found that the T was close to fail because some of the tiny particles of plastic from the heater T were about clog heater core.

Actually I think you might be on to something, when I got my cruiser back in November I did replace the heater Ts myself with metal ones because the plastic ones were very very brittle. It’s possible and I’d say even probable that some pieces fell in. I’m that case should I look into flushing the system?

 

[Kamran Khan]

Actually I think you might be on to something, when I got my cruiser back in November I did replace the heater Ts myself with metal ones because the plastic ones were very very brittle. It’s possible and I’d say even probable that some pieces fell in. I’m that case should I look into flushing the system?

Flush it but remove temperature thermostat. That way you will be able to circulate coolant easily and you will also be able to inspect that temperature thermostat is not crusty, stuck open or stuck closed.

 

[Kamran Khan]

Just one thing before you flush coolant. Remove your heater T, disconnect rubber hose that is attached to heater core close to firewall and inspect if any broken plastic pieces are blocking any hoses or pipes.
Keep in mind if the heater core gets clogged, it’s not an easy task removing heater core. For that you have disassemble the the whole dash board to reach the heater core.
Inspect those hoses carefully before you flush heater core and radiator.
I used a needle nose plier to remove plastic particles that were about to get inside the heater core inlet and outlet pipe.

 

[2001LC]

I often flush heat cores, to remove bits of tee plastic. Using compressed air. I blow air (15 to 30 PSI) into return side (passages side) large/top hose, for front heater core. I place a catch can on driver side. I do same for rear heater (lower/smaller hose), if any reason to. I do this during Tee replacement. If not blown out, before running engine. I've found plastic from tees at thermostat.

BTW: With T-belt service. Thermostat is not typically replaced. Not even removed from water inlet/cap.

 

[cruisin4bruisins]

I often flush heat cores, to remove bits of tee plastic. Using compressed air. I blow air (15 to 30 PSI) into return side (passages side) large/top hose, for front heater core. I place a catch can on driver side. I do same for rear heater (lower/smaller hose), if any reason to. I do this during Tee replacement. If not blown out, before running engine. I've found plastic from tees at thermostat.

BTW: With T-belt service. Thermostat is not typically replaced. Not even removed from water inlet/cap.

Thank you! I figured the thermostat was replaced but I specifically didn't ask for it to be when i got the timing belt replaced, thats good to know. I will be attempting to flush this weekend wish me luck lol