4-RUNNIN' FREAK

Searched 17 pages.

I haven't been driving my truck a lot in the last month and a half.

I got in it today to go out, and it was a little chilly outside, so I crank up the heat. Nothing, air that is just a little warmer then the air outside is coming out.
The heat for the rear passengers works well though. I though it used to blow more heat, but I am never back there and hardly ever use it.

I flushed the coolant maybe 3 months ago, I read in a few posts that it can be that the coolant level may be low, which I didn't check yet, but why would the heat in the back work and not up front?

Lt. Dan

You must have seperate heater cores. The one for the front must be partaily blocked. Other than that, I can't think of any reason why the back is hotter than the front.
(I have never torn into my heater core, so I woulden't know where to start)
Maybe the back is flowing better because it dosen't get used as much?

leebee

the rear heater doesnt go through the heater core, it is direct connect. it will heat up faster than the front because of this. your heater core may be plugged up or blocked, you can try and flush it yourself by attaching a garden hose to the inlet side and running the water through that way, then changing the hose over to the outlet side and repeating the process. if that doesnt work, then any reputable radiator shop should be able to clear it for you.

lee

4-RUNNIN' FREAK

Thanks fellas.



It shouldn't be anything major tho? I mean it's an '02 with like 35,000 miles on it. Just don't want them telling me it's something major.
I saw a few posts that mentioned water pump and impellers missing... could that be a place to check as well?

rimpainter.com

Did the heat up front eventually get hot, or did it just stay luke warm, even at full operating temp?

4-RUNNIN' FREAK

It wasn't even luke warm. Just a little warmer than outside, not much differance.

It stayed the same way the whole time driving.

Now that I think of it, the A/C didn't feel too great either, but I didn't have it on for too long 2 minutes the most.

rimpainter.com

You should be under warranty, right?

4-RUNNIN' FREAK

Negative... I was out of warranty in June.

rimpainter.com

That sucks. Is there a fuse for the heater? If I remember right, a lot of the "switches" and climate control on the 99+ is electronic vs. lever activated. Since you have no heat, I wonder if it is an electrical problem. Hmmm...

How about downloading the heater troubleshooting guide from the FSM via the TIS website? $10 for a day pass. Not a bad deal if you have a multi-meter and some time.

4-RUNNIN' FREAK

I was thinking about a fuse too. I'll check the fuses tomorrow.

If it's not a fuse, I'll just bring it in somewhere and give them a short list and have them take care of it.

runethechamp

That happened to my 94 4runner, and it turned out to just be some small hose that was disconnected. It took the dealer about 15 seconds to fix. Sorry I don't have any more details.

GSGALLANT

Since you mention that you recently flushed your cooling system, you might have air in your system. The following thread talks about bleeding the cooling system after a flush. That would be easy to try... just make sure your heater controls are all set to hot when you do this.

https://www.yotatech.com/forums/show...=coolant+flush

t8jones

did you ever get this fixed. I am having the same problem. What was it.

4-RUNNIN' FREAK

It seems to work better now, but still not hot like it once was.

I was thinking it may be the water wetter I put in, but I guess not.

It more or less seems to come and go. One day it'll get hot (not liek it used to) and one day not so great.

leebee

just an afterthought, check the valve under the hood to make certain the mechanism is working properly. im not sure if it is in the same spot as the 1st & 2nd gens, top of the firewall near center. there should be a cable coming out from the firewall going to the valve that opens it for the water to cycle through the heater core. have someone in the cab operate the hot/cold switch or slide and watch to see if the cable actually moves the valve. you might have to replace the small metal clip if the cable is sliding in the old one.

lee

MTL_4runner

There are a few things to check on this. The first is to disconnect the heater core lines at the firewall and use a hose with a spray nozzle to force water through the heater core (both directions). If water flows fine there, then you should check the heater valve at the firewall too (set it to open by setting inside controls to high heat) and use the hose to verify that water is flowing through. If all is well, put it all back together and fill with coolant. Next, get the engine up to temp and ensure the thermostat is opening by feeling the upper heater hose (it should be hot when the engine is warmed up). If all that looks good, your problem is on the interior side. Next, look at the doors which allow heat to flow (might be a stuck door since your AC was poor too). The controls might be more difficult to diagnose since they are electronic and controlled by servo motors on a LTD.

t8jones

leebee, what do you mean "if the cable is moving inside the old one"? I checked under the hood, and the cable does push the valve when someone indide the car toggles the switch. If the switch is opening, but the air is still cold, does it mean that the controls are ok? The 2 heater hoses going into the firewall get hot, but no hot air is coming out of the front-only the back.

leebee

oops! i should have put the word 'clip' in there, sorry. the two hoses, one intake, one outlet, if things are working the way they are supposed to should be hot on both sides. if the inlet only is hot, your heater core is blocked. if both are hot, you should be getting heat as the coolant is flowing through the heater core.

have you tried flushing the heater core as both jamie and i have explained? that would be a first place to start. burping the system, to expel any trapped air would be the second item to tackle. call a reputable rad shop and explain to them what you are experiencing and ask them their thoughts.

let us know what transpires.

lee