Little to No heat

[185Runner]

My heater seems to be very intermittent. Sometimes I'm sweating and others I'm confused if it's even on. The running temp is consistent 181-188* the heater hoses to and from the core are hot/warm respectively.

Air through the ducting flows well, just mostly seems to be cold.

Any suggestions?

Thanks guys!

 

[TXLX1]

If the running temp is good, the thermostat would have to be good still. I'd guess the temp mode door are sticking but you would probably detect that when you slide the adjustment. Only other thing could be a clogged heater core.

 

[Toyotayoda]

is the antifreeze low? super common with those symptoms.

 

[185Runner]

is the antifreeze low? super common with those symptoms.

Nope checked that too. It's the weirdest thing!

 

[185Runner]

If the running temp is good, the thermostat would have to be good still. I'd guess the temp mode door are sticking but you would probably detect that when you slide the adjustment. Only other thing could be a clogged heater core.

The slide works smoothly from left to right. Also wouldn't the outlet heater line be cold if the core was plugged?

 

[gigipro]

Heater problem

I wonder if heating/cooling problems are common. I so love my 4runner but think I can't keep up the work on cooling system. Seems to go bad when I have used the heat or defrost. AC has not worked since i bought the car second hand, but I've had good use of it for eight years. Replaced radiator twice though. Sorry for your trouble I have wondered about a leak in the hose connection for heat or defrost. I'm uninformed about mechanics, but I mention it because if this system is giving problems, you may be able to head off other work by finding the cause there.

 

[Beaumont67]

I've driven a lot of 15-20 year old trucks & a few SUV's.
- living in Canada, defrost & heat is utmost important, come the 1st snow fall
- freezing temperatures plays havoc, just like on the battery condition / the radiator is put to the real test, of clearing the windshield

Had a 15 year old Pathfinder & when the heater failed to heat, told the head mechanic to put in a new radiator.
- when I went to pay the bill / $75 for a 3rd party test & $150 for new unit
- old rad failed 3rd party test, and was a big waste of money (told shop owner & never returned)
- rad was old and new is usually a cheap fix / doesn't take a rocket scientist to know a 15 y/o radiator, has fulfilled its design obligation

Last week, my 2000 SR5 heat/AC switch was stuck, froze in one position & my heater fan only worked on high.
- the fan housing/plastic flapper door was malfunctioning / cracked plastic hinge
- new housing was $1,300 plus tax, from dealer / sourced a mint used one out of MI wreckers, for $150
- the dash had to come out / big job, so replaced heater core & new AC evaporator (both Spectra brands-identical to OEM-Made in Canada)
(to save extra labor, down the road / like a 10 hour job, when dash totally removed)
- the Low-Med-High fan selector was fixed with a new Toyota resistor ($45 part) / original plastic case cracked...located behind glove box

^^ My Gen3 radiator was new in 2010, with limited driving miles since / low heat is usually clogged radiator fins, from calcium/pH corrosion.
PS - my blinkers stopped working / had dust behind my 4 way flasher...cycled the 4 way on & off a few times / blinkers fixed.

 

[185Runner]

I've driven a lot of 15-20 year old trucks & a few SUV's.
- living in Canada, defrost & heat is utmost important, come the 1st snow fall
- freezing temperatures plays havoc, just like on the battery condition / the radiator is put to the real test, of clearing the windshield

Had a 15 year old Pathfinder & when the heater failed to heat, told the head mechanic to put in a new radiator.
- when I went to pay the bill / $75 for a 3rd party test & $150 for new unit
- old rad failed 3rd party test, and was a big waste of money (told shop owner & never returned)
- rad was old and new is usually a cheap fix / doesn't take a rocket scientist to know a 15 y/o radiator, has fulfilled its design obligation

Last week, my 2000 SR5 heat/AC switch was stuck, froze in one position & my heater fan only worked on high.
- the fan housing/plastic flapper door was malfunctioning / cracked plastic hinge
- new housing was $1,300 plus tax, from dealer / sourced a mint used one out of MI wreckers, for $150
- the dash had to come out / big job, so replaced heater core & new AC evaporator (both Spectra brands-identical to OEM-Made in Canada)
(to save extra labor, down the road / like a 10 hour job, when dash totally removed)
- the Low-Med-High fan selector was fixed with a new Toyota resistor ($45 part) / original plastic case cracked...located behind glove box

^^ My Gen3 radiator was new in 2010, with limited driving miles since / low heat is usually clogged radiator fins, from calcium/pH corrosion.
PS - my blinkers stopped working / had dust behind my 4 way flasher...cycled the 4 way on & off a few times / blinkers fixed.

I have a brand new radiator too. Month or two old now. Had it blow on a trip to Seattle. Needless to say new fluids and rad. Rad level is good.

 

[thegipper]

The only thing left really is a clogged heater core. You can try flushing it out with a garden hose but be careful that you don't apply too much pressure and rupture the core.

Some people pour in CLR and let it sit for 15 minutes before they start to flush it out with water. Make sure you flush it out in both directions.

 

[jkeith.w]

On my '96, the cable housing for the slide came unclipped behind the dash (the sheath is held to the plastic vent box/assembly if memory serves) - so that even though the slide could be moved left-right, the cable itself did not slide in the sheath.

BEFORE you do ANYTHING look up in there fro the passenger footwell while moving the slide back and forth and see if your cable sheath has come unclipped from its fixed position!

 

[nc-grayson]

On my '96, the cable housing for the slide came unclipped behind the dash (the sheath is held to the plastic vent box/assembly if memory serves) - so that even though the slide could be moved left-right, the cable itself did not slide in the sheath.

BEFORE you do ANYTHING look up in there fro the passenger footwell while moving the slide back and forth and see if your cable sheath has come unclipped from its fixed position!

This! I was thinking to start simple and check to see if the cable came unclipped!!!!!

 

[alumarine]

Is the heater control valve on the firewall operating correctly?

 

[nevada]

My heater seems to be very intermittent. Sometimes I'm sweating and others I'm confused if it's even on. The running temp is consistent 181-188* the heater hoses to and from the core are hot/warm respectively.

Air through the ducting flows well, just mostly seems to be cold.

Any suggestions?

Thanks guys!

sounds like the blend door.

lay under the dash while switching the hot/cold controls. you should be able to see the problem.