Asha'man

I'm so ****ing pissed right now. I just spent my day replacing the heater core in my '85 2wd pickup because it wouldn't blow hot air at all. Checked the valve - fine. Backflushed the old core till it ran clear and tested it. Still no heat after that, so I pulled everything apart and replaced the core. Got it back in and together enough to test, filled up the system and warmed up the truck, and I still haven't got **** for heat. It trickles out of the floor vents and is lukewarm (at least that's warmer than it used to be) but the air coming out of the dash vents is minimal at best and is mostly cool. I don't have **** for airflow either. What the **** is going on here?

a4runnerfreak

Did you check your blower motor, and relay, and switch? Those are the only things I can think of to check 'bout your airflow. As for your low heat with new heater core, I haven't the foggest. You are running a t-stat, right? Right mixture of water and coolant?

NYChopshop

there is also a fairly complex set of baffles that move around when you select the different output locations. You should hear the baffles shifting and closing when you move the selector knob. Do you feel air coming out of any or all of the vents? which ones? Does it all appear to work normally but just blows cold? Are you sure you sealed up everything and didn't reverse the polarity on the blower motor for some reason? That would sure make it hard to get hot air into the car! Light a cigarette or incense or something and put it in front of the vents to see where the air is going.

NYChopshop

also try driving your vehicle at highway speeds (or fast road speeds) and crack the windows. turn the heat on. If the blower motor isnt functioning properly, there still should be enough positive suction put on the system to pull hot air out of the vents into the cabin. You could feel that, best done with a non-moron buddy if you've got one. I'm currently in short supply myself.

iamsuperbleeder

I use to do that when my blower motor resister went out

didn't see anyone say anything about it yet, but are you positive you got all of the air from the coolant system? trapped air can cause little to no heat as well

a4runnerfreak

Ah, I knew I forgetting something!!!! Proper burping...

myyota

Its possible that the heater duct between the fan housing and heater is full of leaves and crap and needs to be cleaned out, other than that, check the cables that operate the different heater functions, they can break or come loose and that will cause things not to work.

NYChopshop

best idea ever. I totally spaced on that. I have radiant in-floor heating in my house back in New York, one year I forgot to bleed the air out of the pipes and nearly froze half of the pipes in the concrete with the furnace chugging away on high! narrowly averted catastrophe there.

schmooot

sounds like you've got an air bubble. Warm the truck up until the t-stat opens, Jack the front of the truck up so that the rad cap is the highest point in the system and slowly remove it. Then run the truck with the heat cranked and it should empty the air out. Then you may need to top it all back up

abecedarian

You probably already noticed- you have an inlet and outlet to the heater core. basically, the coolant leaves the bottom of the intake manifold, goes behind the engine and up to the flow valve then to the heater core. From the heater core it comes back through the firewall and connects to a pipe that leads to the inlet side of the water pump.
If you disconnect the hose from the pipe that leads under the exhaust manifold to the water pump, then put the heater on hot and crank the engine over, you should get coolant flow from the heater. If you get nothing out- the problem is a clog back towards the heater core- possibly even in the intake manifold. If you get coolant, the pipe to the water pump may be clogged.

Asha'man

Well, I pulled the truck up on a little hillside by my house and burped the system. Got a few bubbles but nothing real impressive. Pulled the dashpad off, finishing destroying it in the process, and got a good look at the broken HVAC controls. The pivot point for the COOL-WARM and the VENT-BI-HEAT-DEF levers had broken off and it was all jacked up. I took a 6/32" hex head machine screw, two 3/16" washers and a nylock and made a new pivot point for those levers, and it felt better and smoother than stock. I adjusted all the cables and pushrods to exactly where they needed to be, and it was perfect. With all those things done, I finally started getting heat. Which was good, because I had to drive the 2wd through 6" of completely unexpected snow on the way to work this morning....

Thanks for your input, y'all.

iamsuperbleeder

good job; glad we could help

NYChopshop

good to hear you finally got this one taken care of! I suppose if it craps out on you again (or maybe even before it happens), you can cruise over to a salvage yard and pull a spare. Us 2nd gen 'runner owners are a bit spoiled having a wholly separate heating element and electric fan built in to the center console for the back seat in case our main craps out on us.

dub tek

are there engine water/coolant lines to a core like a front set-up?

is this rear heater box internal/built-into the center consol?
or does the consol bolt OVER the heater box??

AKA is it a separate unit with core+blower in one box that I could maybee possibly mount in the rear of my first gen...

NYChopshop

its a separate core and blower in one box that well may be mounted in your first gen. I think that would be super cool! you'd have to make the center console fit, but that shouldn't be too hard. The controls, fan, and water to air exchanger are all in the console. I think there are two coolant lines, one send one return, under the body and electrical wires to the fan. I've never had mine pulled up, personally, but I havn't searched the forums for a thread on it yet so I can't guarantee it hasn't been attempted or whether its truly even possible.

drew303

all these replies about coolant...

he clearly stated that he was getting a lack of airflow, over lack of heat -> If no air is moving your not gonna get warm air.

Glad he found the problem tho.

I have to tear into mine and unclog the vents.. full of leaves, ugh. such a pita.

874runnersr5

i hate thoese stupid piviot points, i replaced mine a while ago... then last week it broke off

i just gave up lol.

Skoalbandit

i know i'm digging up an old thread, but is it possible to take the console with rear heat and rig it into an xtra cab pickup with bucket seats? anyone try it? in my head it makes sense and seems like it could work... the heating system in the dash is crap in my truck, and am ready to bypass the heater core to avoid being anymore frustrated with it. but if i bypass the front system, could i rig up the 4runner rear system to work? just a thought...

RobD

Though I have no first hand experience with that, I don't see why it wouldn't work. All the rear heat is is a small fan and heater core. You should be able to make it work quite easily. I love mine, because it blows some hot air up around between the seat and the front door. Very nice in the extreme cold.