inside heating problem

[Mike_Fho_runner]

Hi! i have this very weird problem with the heat in my trcuk.... i think the engine gets hot very normally, but the heat doenst come out the inside... i know it could be so many problem, so i checked the coolant level, i fulshed, cleaned twice my coolant radiator and system, i replaced the thermostat, and yet nothing changed... the heat doesnt come out until im actually driving, if i let it run it come out cold if i push the gas pedal it comes out warm and as soon as i leave it it goes back to cold..... and lets not even talk about the rear heating... its often very cold in montreal and i cannot understand this problem. another weird thing is that whenever i push on the gas, the lights get brigther and the heating fan blows stronger, but the alternator is new from 2 years... so i dont thing its broker........just give me your advice or tell wath u didi if u had the same problem..... cause i dont think its normal!

[sufkaaron]

I've got the same problem, tried the same fixes with the addition of installing a new, bigger battery now - hasn't helped. A coworker of mine suggested it could be a vacuum leak, like the door between outside air and heated air opens at idle, closes when the vacuum increases. What I don't know, is if the system in a 4runner uses vacuum to open/close the door.

I do also have a problem with the valve to the heater core (on the engine side of the firewall). It is stiff and changing the temp is difficult, don't know if that's a potential cause.

[Mike_Fho_runner]

Hi!
wath i did to solve this problem is simple.. touche both hoses from the radiator (engine compartement) the top hose to your left and bottom hose to your right. if one of them is cold or not really hot after youve been driving your truck, this means you have a problem with the inside rad (the one that heats up your truck) it was a simple fix for me. i unpluged both hoses from the rad (engine comp) and left them attached at the other end. (of corse i emptyed the coolant first, when it as cooled down) then once everything empty. i pluged a garden hoses into the bottom hose (that was cold on my truck) fitted inside very snugly add a clamp around the hoses to make sure it stayes there, then tturned on the garden hose full blast until water comes out from the top hoses and till it comes out clear. didi the opposite starting from the top hoses, but water wont come out because the thermostat is closed, but only to make shure nothing is stuck inside, then back to the bottom hose a few times to make shure. and then put back the hoses to the rad fill it ut, let run the truck to make shure the eat is coming out , And it did!! make shure to leave your fan to the "hot" selection. the rear fan also. it might work and i hope it does for you to.. i now have a 4runner with super heat inside. good luck

[forest_grump]

As far as the lights going brighter when gas is stepped on....might be idling a bit slow(just increase idle a bit if throttle chamber is clean where throttle valve closes inside*no gunk build up*...clean chamber first with a rag damp with a bit of WD40 and do not spray any into throttle chamber),or it might be time to hit up autozone or a parts store to give you a free charging system and battery load test...see what comes from that and let me know....goodluck

[forest_grump]

Hey lol....do you guys just have the problem of lights getting brighter when you use the A/C...if so it is normal for alot of vehicles (weird I know)to have A/C engaged at certain heater selections....if you only have this problem with heater on then don't worry about it,but still clean those filthy,nasty,airflow choking at idle dirty throttle chambers...goodluck lol

[BCowley]

Hey guys,
I would have to agree and say it sounds like a vacuum problem, not sure if there is a vacuum system in the 4 runner though. I had a similar problem with my 2000 Dakota..amongst others... ill never buy a dodge again. But the problem I had with that was when I had the air on..or anything coming from the dash vents for that matter..i would get no air unless i put it under hard throttle, well after 5 trips to the dodge dealer, finally driving back into the service bay and blowing the horn till I pissed everyone off it turned out to be the vacuum line. ok so i wanted to vent about my shitty ass dodge, but yea sounds like a vacuum prob to me.

Brian

[sufkaaron]

I'm still wondering about this "heater control valve" that is mounted on the inside of the fire wall. It has a cable from the temp. control lever on the dash. It also has lines from the radiator and to the heater core. Maybe that's what got flushed out by Mike's method? I can't seem to find a replacement for it either.