1995 4 Runner No Front Heat

P

project240

New member
I'm having some problems with my runner. When I'm driving, I get absolutely no heat from the front vents. It blows cool air only, doesn't matter if it is on recirculate or fresh air.

The rear heat works fine, pumps out great heat.

If I leave the vehicle idling for an extended period of time, the front vents will blow some warm air, but that almost immediately turns to cold when i begin driving.

I just had it in to the local toyota dealer and they basically told me it could be your thermostat, maybe your heater core is plugged... sounded like they had no idea what they were talking about...

Now neither of these solutions make sense to me since the rear heat is working fine. I was thinking maybe the hot air flaps are stuck shut on the firewall, but I can't think of anything else.

Has anybody ever had a similar problem? Please help. It's winter and -25 feels so much cooler with no heat in the vehicle.
 
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Give the heater core a good flush, if your temp geuge
is at normal temp its not your thermostat. use low pressure
or you will blow a hole in it!
 
I assume your engine is warming up and get hot. If your thermostat was stuck, your car would over heat. The rear heater is a heat element, not based on water temp. Before you check the heater core, check the water heat valve along the firewall to make sure it's opening up when you set the heat setting to hot. Not sure if it's a vacum line or cable.

Good luck.
 
project240 said:
Why would my rear heat still work fine if my heater core is plugged? ...
Click to expand...

Because the rear heater has it's own core. It's completely independant of the front.

The front core could be clogged.
The front core could have an air pocket preventing proper coolant circulation.
Does the HVAC system use vacuum motors or hard cables like older models ? If vacum motors you could have a vacum leak stopping the heater valve from moving to hot.

Look under the hood on the firewall and see if the valve changes position when the hot/cold control is moved.

When the engine is hot and running feel both heater hoses, both should be hot.
 
fourwd1 said:


Look under the hood on the firewall and see if the valve changes position when the hot/cold control is moved.
Click to expand...

Where exactly is the valve? I think I found the 2 heater hoses, about 1/2" thick with a foam covering? If this is correct, both were indeed very hot.

I assume the valve is probably very close to the hoses, but I'm not sure exactly what I'm looking for. Could someone please clarify for me?

Thanks in advance.
 
FISH HUNTER said:
I assume your engine is warming up and get hot. If your thermostat was stuck, your car would over heat. The rear heater is a heat element, not based on water temp. Before you check the heater core, check the water heat valve along the firewall to make sure it's opening up when you set the heat setting to hot. Not sure if it's a vacum line or cable.

Good luck.
Click to expand...

If the thermostat was stuck open your truck would not warm up
just adding my two cents.
 
Sorry about that, I meant stuck closed. So the water in the block would recirculate and not cool down. I was told the car would warm up, but would but not get as hot at the most efficient operating temp of 180 degrees?

thanks
 
Assuming the thermostat was stuck, wouldn't toyota mechanics be able to diagnose this? I don't think that's what it is, but it was in for service and they basically said I could try replace the thermostat or try replacing the heater core, but one or both may result in no change.

Does anybody know where the valve is so I can at least check that out? Thanks. I need heat!!
 
you said both the heater hoses were hot so that means
your heater core is hot so all you need is air passing through
it into the truck. is the cable broke on the heater control? it could be stuck on cold not opening the flap in front of the heater.
 
toy4 said:
you said both the heater hoses were hot so that means
your heater core is hot so all you need is air passing through
it into the truck. is the cable broke on the heater control? it could be stuck on cold not opening the flap in front of the heater.
Click to expand...

How can I check this?
 
I have a 94 4Runner in Tahoe with the same problem and symptoms, and I'm freezing my lug nutz off.

The heater control valve is mounted high on the center of the firewall, a little closer to the driver's side, and shuts off the flow of hot engine coolant to the heater core. It is shaped like the letter D and has waffle type cross hatch pattern on top. Underneath it is a lever with a cable connected to the hot/cold lever on the dash. The hoses that attach to mine do not have any insulation, they're just regular rubber heater hoses. Here are pictures of it (the valve is shown, but the lever is not), NAPA charges $36, Toyota charges $97:

http://img.eautopartscatalog.com/live/R3020121024AIR.JPG
http://catalog.drivewire.com/drivew...del=4RU-V6-003&category=All&part=Heater+Valve
Select Brand

TOY4, does the "Inside/Outside Air" lever on the dash control the air flap in front of the heater core you spoke about?? It seems to me that even if it was stuck/broken in the "outside air" position that that wouldn't completely suck off all the heat coming from the hot heater core. With the fan on high, my heater blows a high volume of frigid air even when the truck is warmed up and parked.

I had to have my radiator replaced last summer, and I think this might be a clue. I read in another post on this forum about an 88 with no heat, and the advice seemed to be that the heater core had an air blockage that prevented the water circulating. The guy said that that fixed it. How can air get trapped in a heater core and not get pushed through by the water? And how would I force the air out?
 
Last edited:
i dont think its the valve he said before that the heater hoses are both hot so that tells me hot water is flowing through the core.
 
Last edited:
The heater hose needs to be hot after the on/off valve on the firewall not before it, make sure you are looking in the right area, it should be super hot, jus like the radaitor hose, not engine compartment warm. If the heater hose is hot, one can assume water IS going through it and the heater valve is open when you switch the air temp to hot.

Capish?

Good luck.....
 
I checked the valve and the cable is attached and does work properly. Is it possible that the valve flap is still not opening, even though it does move when switched from hot to cold inside?

Can I remove the valve when the vehicle is off and inspect it?
 
Before you start to rip it apart, make sure the return heater hose is also hot. If so then FOURWD1 seems to be correct that your front heater core might be plugged and not the back.

Also you can open the hose exiting the valve but the problem is that you want to do it when the car is cold, but and the water is cool, the engine is re-circulating the water in itself, when the engine is warm and the water is circulating as the thermostat opens up and the water is hot. Does anyone know that when the thermastat is closed and the engine water is only re-circulating, does it also circulate the heater hose water?
 
Did you figure out your no heat problem? I'm stumped on mine and I'm hoping the solution to yours is the solution to mine.

Thanks
 
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