No heat

[rayray61]

Hello all so I have a 98 4Runner SR5 and I have no heat I have changed the radiator the heater core I flush the system I have done everything that I know how to do and theres no heat or very very little depending in the temp. Any ideas?

 

[the_welfare_wagon]

Do you have a rear heater?

Its very possible you have air in the system. Park the car on a slight incline and take off the radiator cap and turn it on. Let it warm up for a minute and hold the RPM(In park) at 1500-2000~ RPM for about 2 mins. If there's air in the system then it should come out. It will also obviously spill coolant out of the radiator top so be prepared for that.

I did this the other day and my heat went from sorta lukewarm to as good as new.

 

[Endlessblockades]

Sorry to be Cap'n Obvious here with a Copy-n-paste - is your valve opening?


HVAC Heater Control Valve

Part Number: 8724035070
Supersession(s): 87240-35070

Fits 4Runner (1998 - 2002)

Heater Control Valve - Repair or Replace
A heater control valve diverts hot water (coolant, or antifreeze) from the radiator into the heater core in your vehicle’s cabin, resulting in soothing warm air. If your heat has stopped working, your Toyota 4Runner may require a replacement heater control valve.

 

[ej86923]

Do you have a rear heater?

Its very possible you have air in the system. Park the car on a slight incline and take off the radiator cap and turn it on. Let it warm up for a minute and hold the RPM(In park) at 1500-2000~ RPM for about 2 mins. If there's air in the system then it should come out. It will also obviously spill coolant out of the radiator top so be prepared for that.

I did this the other day and my heat went from sorta lukewarm to as good as new.

Spill free coolant funnel is the answer to the spilling coolant. It also brings the level higher than the heater core which is usually the highest part of the cooling system.

 

[JBurt]

I had a clogged heater core, and I ran a coolant flush through the system when I changed the coolant and that made a huge difference.

 

[19963.4lsr5]

If you have a properly operating rad cap and a cooling system that is sealed (including the hose to the expansion tank, and you keep your tank level at the upper full mark) any air in the system should be purged in around 3 heat cycles.

Unless you have the stainless piping going to your aux heater those pipes rust out and leak.

As you drive all the air should collect at the top of the rad. Shutting off the engine and air in the block should rise to the upper rad hose.


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[3bears]

If you have a properly operating rad cap and a cooling system that is sealed (including the hose to the expansion tank, and you keep your tank level at the upper full mark) any air in the system should be purged in around 3 heat cycles.

Unless you have the stainless piping going to your aux heater those pipes rust out and leak.

As you drive all the air should collect at the top of the rad. Shutting off the engine and air in the block should rise to the upper rad hose.


Sent from my iPhone using Tapatalk

agree with this. I was recently having issues, and it was the cap and the hose going into the expansion tank.

Its not hard to check if the heater valve is working, turn on and off and see if the lever is moving, and if it is, make sure its not spinnig on the shaft, just be warned, at this age, the heater control valve can be brittle, have read mixed reviews on after market ones.