1997 4runner Heating Issue

[amalik]

Are you positive the slider knob (when you move from cold to hot) is moving the blend door wire? You can see the wire hanging down on passenger side below the glovebox. I have a 97 limited also, and had a blend door issue last month causing no heat. Find that black wire hanging down, and yank it over to the left. See if it fixes your issue.

Reference thread:

http://www.toyota-4runner.org/3rd-gen-t4rs/246176-no-heat-my-truck.html

 

[hampston4]

Had a little time to mess with the truck today. I took for a little test drive and it did have some heat, only for a short time. It would get warm but the longer the fan was on, the heat would eventually go away. I also check my heater core hoses and the return line was luke-warm. So I still have a problem with the heater core not getting enough flow. I am not sure how this could be after flushing it twice and doing a super flush on the cooling system yesterday. I guess all is well as long I do not have to replace the heater core! It is supposed to warm up here starting tomorrow. I will do the CLR trick as soon as it warms up, I just hope this does not mean I wasted two and half gallons of red coolant. But thanks for your all's help, I will post an update when I re-flush the heater core.

 

[19963.4lsr5]

Had a little time to mess with the truck today. I took for a little test drive and it did have some heat, only for a short time. It would get warm but the longer the fan was on, the heat would eventually go away. I also check my heater core hoses and the return line was luke-warm. So I still have a problem with the heater core not getting enough flow. I am not sure how this could be after flushing it twice and doing a super flush on the cooling system yesterday. I guess all is well as long I do not have to replace the heater core! It is supposed to warm up here starting tomorrow. I will do the CLR trick as soon as it warms up, I just hope this does not mean I wasted two and half gallons of red coolant. But thanks for your all's help, I will post an update when I re-flush the heater core.

Use a air compressor and blow air into the line that is the outflow of the heater core. That will break up and crunchies imbedded in the inlet of the heater core.


Sent from my iPhone using Tapatalk

 

[thegipper]

You can just drain your coolant into a clean container and re-use it.

 

[vt325xi]

Flush is often not enough (never in my case) to unclog a heater core. I use CLR, taking off the two heater hoses, putting them in a ''up'' position (to retain liquid into heater core), blow air in the lines to remove coolant, then put the CLR in. Let it soak 1-2 hours (yes) then backflush with a hose garden. Finally blow air to get water out, plug everything back, and bleed system.

Thanks for your suggestion. I tried this for 24 hours and so far it seems that this was the best method to flush my heater cores. I blew out the original coolant from both cores (I have strong lungs). Then poured CLR in and let it sit over night. Tonight I blew out the CLR and poured water into both cores until clean water came out of the pipes. Then repeated this in the other direction. Then I blew out all the water and filled the entire cooling system with coolant and ran the truck. It appears to have worked. Again thank you! It's been -2 F lately and I've been freezing in the truck. I hope this stays working.

 

[hampston4]

Update

All of my heater hoses where corroded with rust and God knows what, so as I was putting CLR in the heater core I removed all the heater hoses and cleaned them. I flushed the heater core for a good 30 minutes in each direction, the water was running clear in both directions. I also replaced the metal fittings that connect the heater hose, the metal connectors were in horrible shape. Getting the hoses off the back of the engine block was a major pain, not a lot of room to work back there. I took CLR and soaked my heater in hoses in for an hour or so, then took a tooth brush and cleaned the inside. I then flushed the hoses with high pressure from the water hose. I think this did the trick, I have pretty good heat now. After letting the truck get to normal operating temp, the heat was blowing hot, and stayed pretty hot. The lower heater core hose is hot now but still not as hot as the top hose, so I may have to do another heater core flush in the future. But as of now I have heat, a lot better than before. The previous owner neglected the coolant system on this truck, I am just glad that I have made some progress. Thanks again for all your all's help.

 

[hampston4]

I thought I would do an update since it was negative 3 degrees here this morning and I had to carry the mail. It did warm up to the mid 20's as the day went on. I didn't have any heat with the sub zero temperatures but the heat did work fairly decent after it warmed up later in the day, only for short periods of time. Turn it on, then turn it off. I took my Runner to a local garage last week and they told me the heater core was bad. They said they flushed the heater core and did blow air through it. The head mechanic said that everything was clear, this confirms that I did everything that I was supposed to do to flush the heater. Their theory was that, the previous owner let the coolant system get so bad that has caused the heater core to fail. They think that coolant is flowing through the heater core but unable to flow to all the channels, fins or ports in the core, its just passing straight through it. Does this make sense? They did not charge me anything, so I know these are honesty people. My question at this point is, can I use something besides the factory 180 thermostat? The truck has a new radiator and maybe staying to cold. Any thoughts?

Thanks

 

[nissanh]

Did you check for the thermostat? I think you don't have a it.

Even if the heater core is clogged, you should get some heat all the time, not only at the beginning.

the symptoms you state seems to indicate that your thermostat is either stuck at fully open or is missing. You can check for it without removing anything. When the engine is COLD (not warm or hot), open the radiator cap and start the engine, if you see coolant is flowing through the radiator, then you don't have a thermostat.

Did you dilute the CLR or used it without dilution? How long did you leave it inside the heater core? Thanks!

 

[hampston4]

I replaced the thermostat with a new one, 180 degree. I have some heat, it heats when the fan is first turned on but it gets cooler the longer the fan is on. I did not dilute the CLR, let it sit in the heater core for about an hour.

 

[hampston4]

Update

It is finally above freezing here today it was 55 degrees, I froze my ass off carrying the mail last week, 7 below zero Saturday morning. My heat was doing the same thing, warm for a little while, would cool off if the fan was on for long periods of time. I decided that I would back flush the heater hoses going into the back of the block, I know I would waste the fresh coolant but I did not care. I do not understand how this much rust could still be in my coolant system but it is still there. I am going to do another super flush tomorrow, supposed to get below freezing again this weekend. But my coolant system is still full of rust.

 

[hampston4]

I ended up selling this vehicle to a buddy if mine, full disclosure of the issue of course. I think that the someone who had owned this 4runner in the past treated it like crap, because I did end up going crazy with flushing and some nasty nasty things came out. I do not think this issue could have been resolved without replacing the heater core.