I've been reading about heater problems for a while trying to figure out why my heater isn't putting out the heat I believe it should. Here's my process so far:

1984 22R

Flushed and back flushed my heater core: no problem getting fluid in and out.

OEM Thermostat: This helped, but it's still not working quite right.

Burped the system. Twice. I'm burping it now. When I squeeze the hoses (all of them), I get a little puff from the radiator but nothing spillworthy.

The hose before the heater valve and after, and from the heater core are hot. So there's hot coolant circulating to the core.

I took my glovebox out and checked the 20A fuse. It's cool. The wiring harness is poky oke so I do not think it's an issue.

I did cut the truck off and pull the relay, the connections were warm? I am not sure if that's what's supposed to happen.

I cannot find the blend door. A couple people told me to check that but I can move the heater control from hot to cold and feel a noticeable difference.

NAPA gave me the wrong radiator cap so I'll be going back for the right one tomorrow.

I'm going to order an aisin water pump as phase one of money throwing. But I'd just like to hear some ideas about ANYTHING else.

Thanks.

 

The blend valve is against the firewall follow the heater hoses. You could have a clogged heater core. If air is in the heater core you should hear the gargle of fluid while sitting in he truck running. You can try revving the engine to amplify the gargle sound. You could Stil have air in it. You also don't mention what engine you have which could be a factor on burping the engine.

 

I have no gurgling anywhere, actually.
Edited post to include engine. Is there a difference between the blend valve and the "heater valve"? I haven't heard the term blend valve, only blend door. So that confuses me.

 

Yes same thing. Maybe I'm calling it the wrong name. You can take the hoses off the heater core and hook up a garden hose to see if it freely flows. Also check the throw on the blend door, meaning, make sure you can move it all the way open to shut. I've see cables go bad and don't move the door fully.

 

Yep, first thing I tried. A *little* bit of stuff came out of the heater core and then it just flowed crystal clear. When pumping water in both directions. I thought about pouring CLR in there and then pumping it out but... It seemed to flow like it should. I don't know if it can just be flowing across the top or if it has a channel going through it and can only flow if completely clear.

 

I can manually move the blend door actuator and it goes from warm to cold air. However the heater valve did have one issue: no controls inside the cab moved the cylinder that is on the driver side of the valve, I had to use some pliers and move it myself. Disconnected the driver side heater hose and there was coolant sitting there; pushed the rod in and the coolant drained into the core. So theoretically it is opening and closing when I'm moving it and isn't making a difference in the temperature of the air coming out. [Hank Hill Voice] Baugh!

 

Does your truck have ac? If not, you will have a square tube behind the glove box that takes the place of the Evaporator. Pull the black plastic box/connector and see if alot of debris is clogging the fins of you heater core.

New one on left and clogged one on the right. If you are getting hot water thru the core but not out into the cab, the below could be a possiblity

 

^^^ good point. Could have debris blocking the core air flow

 

Have not seen that one yet. I'll tear into tomorrow. I didn't mention it because I don't use my 4x4 too much, but the temp guage does start rising in 4lo. I got stuck in my yard and had to use it to get out so it reminded me.

 

A truck with AC, the evaporator will catch all the debris, a truck without AC will let the debris go straight to the heater core. https://www.yotatech.com/forums/f116...trucks-286766/ The plastic piece between the blower and heater core is easy to take out and you might be able to vacuum it out and get it heating better. If you do have the evaporator, the heater core wont be dirty. If the heater core is dirty from not having an evaporator and vacuuming it out wont clean it, you are going to have to pull the heater core which is not a fun job but not as bad as it is made out to be.

 

Yep, my truck has AC. doesn't work, but it's there component wise. If I break the dash down I know I'll replace the heater core while I'm there. Any other notorious fixes I could take care of while I'm in there?

 

Well I found one problem so far, the resistor coil is decimated. Would that seriously make it blow just warm air? I'm gonna replace the heater core while I'm here too. And good grief it needs cleaning. This is really fun though. Besides it's raining and my girlfriend is asleep.

 

Anybody got the part number for the 4 prong resistor? Mine looks like a replacement and doesn't have a number.

 

All the resistor does is give you the option for lower blower speeds. When you have the switch on Hi, it bypasses the resistor. One thing you can do is make sure you have a good control system and that they are not broken, moving freely, and get all the dust cleaned out of behind the dash and the pipes are cleaned out as well. Some get real dirty behind there.

Not sure where to get the part number, I always ask my Toyota dealer as I know the parts guy well and he helps me out. I used to look on line but been so long I dont remember the site. Might check Toyot partsoverstock.com or something like that.

This thread will show how to get several steps done https://www.yotatech.com/forums/f116...4-88-a-278925/ I have seen a few other threads on here somewhere and some on my 88 build below on getting things a part and back together.

 

Got the heater core out. I can't tell if it's "bad" but it's 30 years old for sure. I am leaning towards the heater valve as being the culprit. But all of this needs to be done anyway.

Terry - I didn't see that thread but I did search "Terrys87 Heater Core" and found your thread on cleaning the ventilation system. Man that whole blower motor assembly does not like to come out! And I think the o ring and clamps to connect the tubes to the core is a terrible design.

Lol if none of this works

 

One a replacement core, some parts stores get them from two differnt places. One comes from Tiawan and the other from Mexico. One will work and the other one will not. I forget which one is the one that works and where it comes from. Be careful when installing the c-clips on the heater core, those dont come with the new one and can be hard to find. https://www.yotatech.com/forums/f199...l#post52002149 Here is a bit of more information that I show about the clip. With a new core, the valve on the firewall and controls functioning correctly, it will work. Do you have any seals missing on the firewall? A little draft can make a big difference in the heating.

I did not have my ac drain hose installed on my 85 and it was some cold days this past week and nearly froze my butt off a few times. Got the firewall sealed off and had a nice ride on some cold days.

The blower assembly comes out easy if the condenser is remove first. If you have the ac charged and dont want to open it up, it would be a little more difficult to get the blower out with the ac in.

 

Terry my ac condenser is so clogged up with crud that I'm wondering if I can just leave it out upon reassembling everything. Or would it be best to have it there even if it's not doing anything?

I bent one of the hoses that goes from the core to the firewall. Can't use it. However one heater core I found online has the tubes built in. I might go with that after reading a couple reviews.

I am going to try and rebuild the resistor before buying another. It's easy enough to get to anyway if it doesn't work. One side is toast and one side actually looks OK, I'm wondering if I can solder a piece of copper wire in there and have it working.

 

Copper wire won't work. The copper would not have enough resistance to restrict the motor speed. At best, you might have a second high speed position on your blower switch.

The resistor coils are usually made of a ni-chrome alloy,

Buy a new one, I have bought them cheap on Ebay.

 

The resistor is not very expensive at all. Just make sure you get the same resistor as yours, some are a 3 prong and others are a 4 pronged.

You would need to plug the drain hole if your going to remove your going to remove the evaporator. If you can find a truck that came with out ac, it will have a square tube to replace the evaporator. Not sure how just removing the evaporator and using the case would work out, don't see why it would not work.

 

Heater did blow barely warm air now fan quit working and hot to cold lever has been stuck since I've had the truck. My money pit needs more help