Kellybubba
New member
I just purchased an 86 4Runner that was supposed to come with a working heater. Alas, it blows but the air is not hot nor warm. Any tips on things I should check/replace first that won't cost me an arm and a leg?
Heater not blowing hot in my 86 4Runner
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gtgt_bangbang
New member
Pretty simple system, hot water and air. You indicate you have airflow.
First thing to check is do you have enough coolant- don't know the 86, but the heater core is the high ground in most systems, which lets it red flag a loss of coolant.
Next would be the valve, a wire-cable operated Device hosed to the firewall on my 95, which is supposed to switch hot water on or off into the passenger compartment. Not impossible it is broken internally or corroded in position, but the cable could've slipped off in the "summer" position. Junk yard item.
The on-engine water pump is the only means of impelling water around the system; engine and heater core, so if that was the problem you would probably learn in a hurry when your engine seized up. Look for water movement through the radiator cap, after it's hot but before it's boiling over.
An expertly abused system may have an internal clogs, perhaps not obvious due to possible / recent radiator change, so take a hose off near the heater core (on the firewall) look for sludge. Be prepared for a fight; the the optimistic plan is to remove a clamp and insert a hose detacher (Think 90deg bent screwdriver / pick ) to loosen the hose without breaking something. More likely a light razor cut on the end of the hose will free it from the metal tube that is grown to love, so try pick a hose it looks easy to replace- they are not all equal.
There are possibly some internal flap doors which govern the airflow, shouldn't be too hard to look underdash, although often a huge task to fix. Flap doors are usually downstream of the heater core, so it should be hot somewhere, although an heat+AC system may valve airflow upstream of the core.
Are the water pipes at the firewall hot?
Get a diagram see if all the expected hoses are there, 1986 is a long time to bastardize something
First thing to check is do you have enough coolant- don't know the 86, but the heater core is the high ground in most systems, which lets it red flag a loss of coolant.
Next would be the valve, a wire-cable operated Device hosed to the firewall on my 95, which is supposed to switch hot water on or off into the passenger compartment. Not impossible it is broken internally or corroded in position, but the cable could've slipped off in the "summer" position. Junk yard item.
The on-engine water pump is the only means of impelling water around the system; engine and heater core, so if that was the problem you would probably learn in a hurry when your engine seized up. Look for water movement through the radiator cap, after it's hot but before it's boiling over.
An expertly abused system may have an internal clogs, perhaps not obvious due to possible / recent radiator change, so take a hose off near the heater core (on the firewall) look for sludge. Be prepared for a fight; the the optimistic plan is to remove a clamp and insert a hose detacher (Think 90deg bent screwdriver / pick ) to loosen the hose without breaking something. More likely a light razor cut on the end of the hose will free it from the metal tube that is grown to love, so try pick a hose it looks easy to replace- they are not all equal.
There are possibly some internal flap doors which govern the airflow, shouldn't be too hard to look underdash, although often a huge task to fix. Flap doors are usually downstream of the heater core, so it should be hot somewhere, although an heat+AC system may valve airflow upstream of the core.
Are the water pipes at the firewall hot?
Get a diagram see if all the expected hoses are there, 1986 is a long time to bastardize something
Last edited:
grumpin
New member
When I got my 87 I could not control the heat. The cable had come off at the control in the dash. I found the cable was very stiff. I kept putting a little lube at the control cable at the control valve. It finally loosened up. The other thing that comes to mind is that there is no thermostat in there, someone took it out. But I would think you would get some warm air.
Kellybubba
New member
Ok Ya'll, i'm going to see what i can tell from what y'all said.
One thing i did notice is that there is a fuse box under the hood close to the battery. I forget what all is labeled on it but it's pretty small. One of the labels says "Heater" but there is nothing underneath it. Not even a place to put a fuse. Any idea what that is?
Also, where can i find a diagram? Would love an owners manual for this car...
J
One thing i did notice is that there is a fuse box under the hood close to the battery. I forget what all is labeled on it but it's pretty small. One of the labels says "Heater" but there is nothing underneath it. Not even a place to put a fuse. Any idea what that is?
Also, where can i find a diagram? Would love an owners manual for this car...
J
flyinhawaiian01
New member
the manuals can be found online, not sure if these are still available, but you can start here:
http://www.toyota-4runner.org/classic-t4rs/35863-free-factory-service-manual-downloads.html
The 85-89 trucks "should" have the same parts and layout as your 4r for the most part, but you should verify that by going through and making sure it looks/acts exactly like your model! I've learned a helluva lot here about the little differences in these trucks/4 runners! :nod:
As for heat, the above posts pretty much have it covered. Check the antifreeze level first. If good, check to see if the lever is operating properly for the heat. It should move the valve on the firewall iirc (or is that my supra? I can't remember!). If it moves, then check to see if there's a thermostat. easiest way is to see if after a while of driving, the temp gets above the cold mark! If its not around the halfway mark (below that), you might not have a thermostat in there. Easy fix, so long as you don't snap one of the bolts on the water neck!
If it gets hot around the middle mark on the gauge, then its either a plugged-up heater core, bypasses heater core or the cable isn't operating the valve to allow water into the heater core.
I don't think there's a way to not get heat from the vents when the lever is on full heat.
One final thing, if you turn the heat to full hot and hear gurgling when you rev the engine slightly, you have air in the system! Try bleeding the system by parking the car with the front pointing up. You'll want to be around a 20-30º incline if you can. With a cold engine, pull the radiator cap off, start the truck and let it idle till its warmed up. That should get all the air out (the radiator cap being the highest point in the cooling system). It will also tell you if you have a thermostat, as you will not see any movement of water until the thermostat opens up. Once it does, you'll see water flowing through the top tank.
Good luck and let us know what fixes it!
http://www.toyota-4runner.org/classic-t4rs/35863-free-factory-service-manual-downloads.html
The 85-89 trucks "should" have the same parts and layout as your 4r for the most part, but you should verify that by going through and making sure it looks/acts exactly like your model! I've learned a helluva lot here about the little differences in these trucks/4 runners! :nod:
As for heat, the above posts pretty much have it covered. Check the antifreeze level first. If good, check to see if the lever is operating properly for the heat. It should move the valve on the firewall iirc (or is that my supra? I can't remember!). If it moves, then check to see if there's a thermostat. easiest way is to see if after a while of driving, the temp gets above the cold mark! If its not around the halfway mark (below that), you might not have a thermostat in there. Easy fix, so long as you don't snap one of the bolts on the water neck!
If it gets hot around the middle mark on the gauge, then its either a plugged-up heater core, bypasses heater core or the cable isn't operating the valve to allow water into the heater core.
I don't think there's a way to not get heat from the vents when the lever is on full heat.
One final thing, if you turn the heat to full hot and hear gurgling when you rev the engine slightly, you have air in the system! Try bleeding the system by parking the car with the front pointing up. You'll want to be around a 20-30º incline if you can. With a cold engine, pull the radiator cap off, start the truck and let it idle till its warmed up. That should get all the air out (the radiator cap being the highest point in the cooling system). It will also tell you if you have a thermostat, as you will not see any movement of water until the thermostat opens up. Once it does, you'll see water flowing through the top tank.
Good luck and let us know what fixes it!
Kellybubba
New member
Ok, thanks again. All of this helps a ton...
I'll report back as soon as I get to the bottom of it. I know i had a lot of wires removed last month as the previous owner had all kinds of electronics rigged up in it including 2 power outlets, 2 amps, 2 subs, and an alarm with power locks and remote start... It was gross... Maybe in the removal of the plethora of wires, something got knocked off.
I'll report back as soon as I get to the bottom of it. I know i had a lot of wires removed last month as the previous owner had all kinds of electronics rigged up in it including 2 power outlets, 2 amps, 2 subs, and an alarm with power locks and remote start... It was gross... Maybe in the removal of the plethora of wires, something got knocked off.
Kellybubba
New member
none of those links worked for me. Does anyone have one they can zip and email to me by chance? (kellybubba at gmail dot com)
flyinhawaiian01
New member
Really? None of them??? Funny, this one worked perfectly for me:
Toyota Tacoma/ 4Runner/ Tundra/ FJ Cruiser Factory Service Manual Page
It takes a while to load, but here's the truck/4runner manual, in case you can't find the "correct" link:
http://web.archive.org/web/20110102225436/http://www.ncttora.com/FSM/87-4Runner/toyota_truck_and_4runner_88.pdf
FYI, I just tested it and it took almost 5 minutes to save it off to my hard drive. And sending an 83mb pdf to your gmail account will not work, as there's a 25mb file limit for attachments.
Toyota Tacoma/ 4Runner/ Tundra/ FJ Cruiser Factory Service Manual Page
It takes a while to load, but here's the truck/4runner manual, in case you can't find the "correct" link:
http://web.archive.org/web/20110102225436/http://www.ncttora.com/FSM/87-4Runner/toyota_truck_and_4runner_88.pdf
FYI, I just tested it and it took almost 5 minutes to save it off to my hard drive. And sending an 83mb pdf to your gmail account will not work, as there's a 25mb file limit for attachments.
Kellybubba
New member
Ok, cool, yeah that one worked.
As for the heater, y'all were right. The wire that protrudes from the firewall that when you move the temp to hot, it pulls a lever in, was not attached to that lever. It had slipped off and it looks like that was pretty easy for it to do. I slipped it on, slid the heat over and Wah-lah! HEAT! now I won't be needing it for quite some time as i live in Austin Texas but at least i know i'll have it once that time comes.
Thanks so much y'all!
Next is figuring out why the electric fan isn't turning on. Today, my mechanic told me over the phone that i should adjust the temp at which it comes on. Well, i can't find a way to adjust that anywhere on the fan. He made it sound like it would be a black box with wires going to the fan. there is a small black box but there is no adjust screw/knob/whathaveyou.
I almost over heated the other day... scary!
As for the heater, y'all were right. The wire that protrudes from the firewall that when you move the temp to hot, it pulls a lever in, was not attached to that lever. It had slipped off and it looks like that was pretty easy for it to do. I slipped it on, slid the heat over and Wah-lah! HEAT! now I won't be needing it for quite some time as i live in Austin Texas but at least i know i'll have it once that time comes.
Thanks so much y'all!
Next is figuring out why the electric fan isn't turning on. Today, my mechanic told me over the phone that i should adjust the temp at which it comes on. Well, i can't find a way to adjust that anywhere on the fan. He made it sound like it would be a black box with wires going to the fan. there is a small black box but there is no adjust screw/knob/whathaveyou.
I almost over heated the other day... scary!
flyinhawaiian01
New member
Glad to hear you got the heater sorted! As for the fan, I'm assuming you're talking about an electric fan for the radiator?
While I have a Flex-A-Lite Black Magic aftermarket fan for my truck, I don't recall seeing a stock electric fan, I could be wrong though.
If its a Black Magic one though, there should be about 5 or 6 wires going to the control box on the passenger side of the fan, inside the box should be a knob to control the turn-on temp. Its usually pretty hard to turn, but its just like a volume knob, keep turning it until the fan kicks on, do this after you've brought the truck up to temp. I turned mine up just ever so slightly from that point when it kicks on. You'll have to let it cool down again and see if it kicks in appropriately.
While I have a Flex-A-Lite Black Magic aftermarket fan for my truck, I don't recall seeing a stock electric fan, I could be wrong though.
If its a Black Magic one though, there should be about 5 or 6 wires going to the control box on the passenger side of the fan, inside the box should be a knob to control the turn-on temp. Its usually pretty hard to turn, but its just like a volume knob, keep turning it until the fan kicks on, do this after you've brought the truck up to temp. I turned mine up just ever so slightly from that point when it kicks on. You'll have to let it cool down again and see if it kicks in appropriately.
Kellybubba
New member
Yeah, it's def not stock. As for it being Black Magic, i have no idea. Previous owner installed it...
i saw the small black box but couldn't find the knob to adjust... But it sounds like from what you're saying, it's inside the box. Is this the same box the Relay is plugged into? I just bought a new relay just in case...
If so, i'll see if i can get into the box and adjust. I'll try and take a pic too so i know we're on the same page.
Kellybubba
New member
ok, never mind. i see the adjustment knob now. it is SUPER DUPER TINY!
Any idea which way is a cooler setting and which way is warmer? Rather, hotter
Any idea which way is a cooler setting and which way is warmer? Rather, hotter
Kellybubba
New member
Ok, well, that was weird. So yeah, it's a small white flathead type screw. I had the car running and turned it about a whole turn to the left (counter clock) and nothing happened other than it seemed to have reach the stopping point of turning. THEN I turned it to the right (clockwise) and it turned and turned and turned as if it had no end. THEN i was like, hmmm let me take it back to the end going the other way again and at least get it back to where it was, then it kept turning that way too. I couldn't find the end again. So weird...
Long story longer, it never came on... :cry2:
Kellybubba
New member
Apologies for the constant posting but i'm working on this today and am trying to get this knocked out over the weekend.
I did test the fan and it does in fact turn on when i run it straight to the battery...
I'm just confused about which part is telling the temperature... I noticed there is a small silver rod that is going from the radiator core to the small black electrical box. I'm assuming this is the thermostat/temperature gauge. My question is, does that just run through any of the cells in the core? if so, i think i should just move it to another cell maybe?
I did test the fan and it does in fact turn on when i run it straight to the battery...
I'm just confused about which part is telling the temperature... I noticed there is a small silver rod that is going from the radiator core to the small black electrical box. I'm assuming this is the thermostat/temperature gauge. My question is, does that just run through any of the cells in the core? if so, i think i should just move it to another cell maybe?
flyinhawaiian01
New member
Oh man! I am trying to remember how I installed mine about 10 years ago!!! I believe the bulb for checking the temp of the radiator was mounted to the front of the fan, just barely touching the radiator, but I really can't remember, and I'd have to pull the fan out to see the setup again!
I found the instructions for mine, here's what I have:
Flex-a-lite 165, Flex-a-lite Black Magic & Electra-Fan II Fans | Flex-a-lite
If you click the link, then click on "INSTRUCTIONS" it should get you to what you will need. See if its the same unit you have first, then go from there.
If you don't mind spending some money on the fan setup, you could get one of these controllers:
Electronic Fan Controller 70 Amp
This is the Cadillac of electric fan controllers! While my truck's fan is still going perfectly and there's no issues with it, I've literally lost a motor on my supra because of the dual fan flex-a-lite box frying a trace inside the controller box! Fan went out, was stuck in traffic and couldn't pull over fast enough, blew the head gasket on the car. Ended up spending a few hundred bucks because of a tiny little solder trace!
Worst case scenario, you could hook up a switch to the A/C trigger in that box, then just turn the fan on manually, although if you forget to, and don't check your temp, you could be in the same boat as I was with the supra!
Anyways, try to make sure you have power/ground at the controller box. You should definitely "feel" a click when you're turning the knob. Its a mechanical rotary switch, and it will click when you hit the spot where the temp is, even if the truck isn't warmed up. I know I can turn my knob all the way down and get the fan to kick on without even with the truck cold and not running.
I found the instructions for mine, here's what I have:
Flex-a-lite 165, Flex-a-lite Black Magic & Electra-Fan II Fans | Flex-a-lite
If you click the link, then click on "INSTRUCTIONS" it should get you to what you will need. See if its the same unit you have first, then go from there.
If you don't mind spending some money on the fan setup, you could get one of these controllers:
Electronic Fan Controller 70 Amp
This is the Cadillac of electric fan controllers! While my truck's fan is still going perfectly and there's no issues with it, I've literally lost a motor on my supra because of the dual fan flex-a-lite box frying a trace inside the controller box! Fan went out, was stuck in traffic and couldn't pull over fast enough, blew the head gasket on the car. Ended up spending a few hundred bucks because of a tiny little solder trace!
Worst case scenario, you could hook up a switch to the A/C trigger in that box, then just turn the fan on manually, although if you forget to, and don't check your temp, you could be in the same boat as I was with the supra!
Anyways, try to make sure you have power/ground at the controller box. You should definitely "feel" a click when you're turning the knob. Its a mechanical rotary switch, and it will click when you hit the spot where the temp is, even if the truck isn't warmed up. I know I can turn my knob all the way down and get the fan to kick on without even with the truck cold and not running.
