Heater not working!

M

mrRev

New member
The heater in my truck for some reason works, and then doesn't work again. Now it's freakin' cold out, and guess how it's acting now? The fan works fine, and lows lots of air, it's just not hot. I did the simple things first, checked for an airlock, changed the thermostat, and even fluched out the heater core. All this to no avail. Then it started to blow heat again. I took the dash apart, and it looks like the slides on the heater box are functioning properly, but obviously there is something wrong. The rear heater blows hot air, but nothing from the main. Does anyone know what to do? My wife hates driving the truck, she can't stand it!!! I need some expert advice. I really don;t want to take it to the dealership, I don't have an extra arm and a leg!!

Thanks
 
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I had the same problem with a Tacoma I owned, I tried some of the same things you did, unfortunately I ended up taking to the dealership, and it ended up being a sensor. $180.00 and it was good to go again.
 
i have a similar problem that i thought id post here:

I recently bought a remote start to warm up my 4runner in the mornings. The problem is, it seems that my heat will only come on when im driving, if its just sitting there and the engine is only idling then the heat doesnt heat up. As soon as i get it moving and the RPMs up, after about 3-4 min of driving and getting the engine going then the heat starts working. Lately ive noticed the heat kind of cools off too if i stop too long at a stoplight or whatever.

But when i start my car in the mornings (temp here is around 32 at night currently) it would take about 20 min of idling before the heat will work from just idling


any help appreciated with this. also i cant bring it to a dealer under warrenty because its not and i got it from a private seller.
 
you might have a broken control cable. I'm not sure about this but you might have a look. at the firewall under the hood, where the heater lines go into the firewall, there might be a shutoff valve that is operated by a cable.
my old celica had this so i'm asuming the 4runner might. your temperature control knob should have 2 cables attatched to the back side of it. 1 cable controls the valve, the other controls an air gate at the heater core. if the valve is indeed there, check to see if the cable has come loose or give the valve a 90 degree turn. good luck.
 
The same thing happened to my 96runner. But now its fixed.


Try this...

THere are two hoses going to your heater core in you engine bay. One which has THE WATER VALVE THINGY on it 'sender', and the other is the 'return'. Take the clamps off (both hoses) and run water thru it with a water hose. Do it several times until you get a nice flow of the water, and of course, until it comes out clear.

Sometimes, the heater core get clogged and wont let water go thru it. By it being clogged, when you rev the engine, you get "some" heat, but as soon as you let go of the gas pedal it gets cold.

You migh also want to consider draining your system and adding new fluid. That will ensure that the whole "heater" unit is clean.




I hope this helps....



Good Luck!:)
 
broncosi said:
ok yea that makes sense, where is the heater core? any pics?

also, what is it getting clogged with?
Click to expand...

The heater core is located under the dash, but there are inlet/outlet tubes coming out from the engine bay area on the firewall itself. arrgghhhhh.. I'll take pictures in a bit and post em'.



Be right back.
 
damn sorry, cant seem to find the camera right now.


anyhow,
so ahh yeah...

Pop your hood and look straight ahead towards the firewall. THere youll see a WATER VALVE thingy. That piece is controled by the COLD/HOT settings inside your vehicle,. Follow the hose thats attached to that water valve and locate the IN/OUT part of the heater core. You cant miss it. Its just 2 tubes coming from the inside of the vehicle thru the firewall.
Take the clamps off, from both hoses coming from heater core and run water thru it with water hose.
When i first did it, it looked like rust or some shit came out. After clearing out both, front and back heater cores, i drained the whole coolin system and filled it with a fresh 50/50 misture of coolant/water.
Now my heater works perfect.



I'll try and find the camera tomorrow and shoot pics.

Good Luck Guys.


edit: water valve is located right on the firewall.
 
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Are your engines warming up to the proper temperature? Or is it taking longer to warm up (the engine temp) than it did before? If that's the case, it could just be the thermostat. I believe they're around $20-30. Easy fix.
 
heater problems

i am having the same problem as all of you guys;;only get cold air /no warm;;the reliable 97 four runner has let me down;;the themia stat was changed;the radiator was flushed;hoses are hott;checked the heater valve is opening properly;all cables are working below near heater coil;;can hear and see the difference from hot and cold;;fan clutch appears good;;pump?everything is hot;;help if you can ;;;toyota has said no coils have been replaced --hard to believe that is an issue(no water leaks on floor)water blown in and comes out;;air condition works;;;help;;sencer??where???
 
just as an update for me from 2006: I just wasn't giving the truck enough time to heat up. After driving, the heat would come on because the engine warmed up faster at that point.
 
It could be that your radiator does not have enough water and when the water travels between the two pipes mentioned in this post, there is not enough water to completely fill the pipes and transfer heat properly. Check your radiator overflow tank first and fill it if you don't see any water. My heater would not work when the car was at rest either and the problem was simply that there was not enough water in my radiator so I filled the overflow tank and viola, warmth again while sitting at traffic lights. Now I need to figure out why my water was low.
 
I went to the local Toyota stealership and bought two gallons of their coolant for $70. Yeah, I know. Ouch!

I waited for the weekend and started my radiator cooling system flush.

Under the hood, I removed the lines for the two interior heater cores (front and rear heater), I flushed them out with low pressure and some nasty rusty colored gunk came out.

I reversed the flow of water pressure numerous times to ensure I 'dislodged' everything I could before closing the lines and flushing the rest of the system.

It was snowing this time of the night might I add, but I really wanted this done because my heater wasn't heating very well recently.

I unscrewed the pet cock valve on the bottom right (passenger) side of the radiator and drained all the old coolant out. The engine was running at this time. I left the pet cock removed from the radiator as I poured water down the top of the radiator and flushed the cold water through the system. After 10 minutes, or so, I put the pet cock back on after all the water drained out.

Turned off the engine, filled the rad. with brand new 50/50 water and Toyota 'red' coolant.

The heaters work well now. The rear heater will put out some hot air initially, but after 30 seconds it begins to cool a bit.

Otherwise, both heaters work well.

I did not replace the thermostat.

27 December 2012 update: The air into the passenger compartment never heats up now. I will replace the thermostat with a 180* one this weekend. Hopefully, that will help with my idle air control valve fault P0505 also.
 
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Bump.

I just had this issue but everything was in place. I adjusted the cable's position on the clamp next to the blend box under the glove box to allow it to fully close.
 
Having similar issues. Replaced the thermostat but still not working right. I will have to try flushing the hose like suggested.

Sent from my SM-G930P using Tapatalk
 
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