I just got this truck. It had a leaking radiator. I replaced it along with thermostat, upper hose, and pressure release cap.

I back flushed the heater core. I burbed the air out I think. I even pulled it up on ramps and hooked a hose up to the overflow tube going up to a funnel. I did have a little heat but now it's gone.

I'm suspecting the water pump since the lower radiator hose is cold. Or does the coolant have to go through the heater core first. And it could be blocked solid.

But what's weird is I did have a little heat before. now there's none.

Please advise.

I'm going to add a sig. But its a 87 base model, 2wd, carb, 22r, 4 speed.

This video might help.

 

You say that you backflushed the heater core.

I rekon that if water came out the hoses, it's not plugged up.

Is the hot water valve open???

 

Are you talking about what I'm calling the heater control valve above where I added the flushing tee? If so, it appears to be working. It's moving as you can see in the video.

 

Yes, that is the heater control, or hot water valve.

It should be noted that when the heater temp control in the cab is moved to open up the valve; at the same time, that same lever changes the position of an air door in the heater box.

If that air door does not move appropriately, there will be little heat even though the hot water is flowing freely thru the core.

 

Do you mean it will change positions of where the heat will come out. Like defrost instead of heat?

 

No, its more of a general hot and cold air blend door that helps regulate the air temp. A different door/doors and control lever change the areas that the air is directed to.

I have an '87 and an '88 4runner tha both have this same control scheme and both required substantial reconstruction and repair in order to work properly. Worth the effort though.

 

You da man,,,lol. I found that other cable tied to the temp lever. It's on the passenger side of the heater box. Right. I moved it and got some heat. I move the heater control valve under the hood and got more heat. So it's working pretty good now.

The control levers have always been jerked off since I got this truck a week ago. I thought it was just the temp lever came off or a messed up cable. Well it did come off, but it's bent all out of shape I think. Maybe from a frozen heater control valve. Who knows.

I pulled the face plate off and the temp lever came out with it. Everything is all busted up. I guess I need a new control panel. Anyone know what years will interchange. Ebay listing all say 84-88. But the junkyard told me 87-89. So someone is wrong,,,lol.

Anyone have a heater control panel to part with?

I tried to get the control panel out all the way but couldn't. What all has to come out to change this thing.

Thanks again.

 

I believe the water pump is not pumping. How can this not be over heating. I see no flow in the radiator. The radiator is just warm to the touch. Not hot. The lower radiator hose is cold. The truck is up to temp. and the radiator is full.

Could the heater core be acting as a radiator keeping it from over heating.

Btw. The heater IS working good now.

 

If the engine is not under large load and the ambient air temp is moderate, the heater core may well take the whole thermal load and not open the thermostat.

Take it out and run it at highway speed for 10 miles or so and I'll bet the radiator will get hot.

As to taking the heater controls out of the dash. Find the far end of each control cable, .free each of them them and tie three feet or so of tough twine to the end of each cable.

This will permit each cable to be pulled backthrough in its original routing.

With the cables free at their far ends, it is possible to houdini the control mechanism out of the front of the dash.

The control on my '87 Runner came out in a pile of broken small parts and I reconstructed it stronger than factory with JB Weld and pieces of phenolic composite sheet.( That red-brown bakelite impregnated cloth stuff that was used in vintage arplanes, both in models and full size aircraft). Other materials would do as well.

Maybe you can find an intact control for cheap, IDK. I never thought about it, I just repaired what I had.

 

Thanks for all the help.

I just bought a control panel with all the cable off of ebay,,,lol. Hopefully I can get it in with out too much trouble.

 

Something to keep in mind if the coolant level is low you don`t get any heat.

The door also needs to be in the fresh air position to get the most heat !!

Aftermarket Thermostats seem to be really junk anymore I am only using Toyota ones anymore .

 

I would assume if it was in the fresh air position it would be letting in cold air wouldn't it?