Here is the list:

Heater core: flows perfectly both ways
Control valve: flows perfect each way
Engine: when hose is hooked up to it, water flows out of the thermostat port, the radiator (both hoses) and the control valve.

Heater still does not work, its not getting coolant while the truck is running. The truck now runs at 190 under load, and 160 at idle. Thermostat is new, boiled it to 185 and it opened, not quickly, but rather slow. water pump has a little bearing noise, but not overly severe. I have tried bypassing the valve, no luck, I have tried bypassing the core, still no luck. I have not the slightest idea what the hell is going on with this truck. Any ideas, logical or bat poo crazy, would be greatly appreciated.

 

Hello there.
A little late to the party, but for what it's worth~

Get the system started and verify the temperature of the hot water going into the coil. Then, verify temp of water leaving the coil. It should have about a 20 degree drop. If the water coming out is way colder, running say a 50°-60° drop, then there's not enough GPM. If the water is still hot at only a 5°-10° drop, then the air is not taking the heat from the coil and that means the air side is plugged or the air is bypassing the coil.

I work with large heating coils in buildings, and maybe the technology doesn't cross over well. Someone could verify (and I might myself) the temp drop #'s, those #'s are from my building experience but I think the physics of heat transfer and coil technology is the very similar for both sizes of systems.

Hope that helps (tho I bet I didn't help at all, LOL )

EDIT: Tho looking at your pics, I'm betting the coil is 80% plugged and there's such small flow that by the time it leaves the coil, it's probably dropped a huge amount and your air is about 5° warmer. Not enough to feel, the fan motor probably adds 1-2° itself.

 

Well, you are close. But, what I found the issue was, there is no coolant in the heater hoses. They remain bone dry. I dont just want to start replacing things, as we all know that can get expensive. Here is a question for everyone, can our water pumps just not push enough water when they start to die? I dont think that its possible with a direct drive water pump, but who knows.

 

Hey, it won't overheat if the heat is on full blast! I'm kinda liking the '88-'89 part idea, actually.

Here's my semi-useful input: you had that much crap in the lines, so the rest of your system is definitely going to have some crap in it. I think you need to flush the system with the heater core bypassed, then flush it with it hooked up to flush the core too. That'd be easier than removing the heater core to flush it out of the vehicle, I think. Not 100% on that though, never tried to remove the core on a Toy, just looks like it's in a pita spot.

 

Well, sunday I will be pulling the heater core out and replacing it, and replacing the water pump along with some hoses. I think I am going to have paul fix it, remember him jonnyboy? STOP RESISTING!!! He said he could have it working fine with new parts replaced in a day easily. Only gonna charge me 100 bucks too.

 

I flushed my core out today to, not much came out then i tore into the ducts and everthing. Make sure your ducts are clean and cabin air filter is good

 

It has no problem with air flow. Its not getting the coolant up to the heater hoses or core.

 

I seem to be having the same problem with my 84 4runner. I am really looking forward to seeing how this issue is resolved. It's gonna be cold soon and I don't want to freeze this winter.

 

hmm, perhaps take apart the hc and just replace it?

 

Yeah, thats what I'm going to do. Heater core, water pump (going out), power brake booster, carrier bearing, and finally the lift springs for the rear. Me and the mrs talked last night and budgeted for a bunch of new parts, and a shell! Now I just have to find a cab-high shell.

 

Im in the same boat. Ill let you know what transpires.

 

Well, have you had any luck with the heater problem yet?

 

I forgot about this thread. The heater core is full of stop leak. I bypassed it till next payday when i can order one.

 

Ahhh......yes, how I hate stop leak.

 

Yuppers, stop leak is in my opinion, the worst thing you can do to an engine.