No Heat !!! 96 4runner - need help bad
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Fan clutch check...
Does fan ever come on? 195 is still cool/just warming up. Does it ever go higher? Engine coolant temp sensor/wiring check :wrench: |
Originally Posted by 75w90mantraN
(Post 52420719)
Fan clutch check...
Does fan ever come on? 195 is still cool/just warming up. Does it ever go higher? Engine coolant temp sensor/wiring check :wrench: I though with the stock 180 degree thermostat, 195 would be normal, it always stays below 200, it is winter after all, so it may go up more with warmer weather. What temperature would be normal if 195 is still cool? I would think 195 degree coolant would be hot enough to at least get some warm air coming out of the heater? My chevy truck stays below 200 in the winter and puts out a ton of heat. If the engine coolant temp sensor/wiring is sending a good signal to the OBD II reader, then doesn't thar prove the wiring and sensor are working properly? AFAIK, the temp sensor or wiring will have no effect on the operation of the cooling system or would effect the ability for the heat to work in the vehicle. I thought the obd temp sensor would only effect the computer for emission purposes. |
You should get plenty of heat at 195°F.
The heater system on these 4Runners is pretty basic, or so we thought..... I assume the line you capped off was only for the rear heater, right? Does the cable that is supposed to open the water valve move the valve open and closed fully? Does the valve physically move open and closed (as in remove heater hoses and look at the inside of the valve)? Are you 100% sure there is no air in the heater core? Is there a lot of debris in the A/C or heater box under the dash? What is the ambient outdoor temperature? I am just trying to find a reason for the heater hoses to be hot but you are still not getting any heat. You seem to have done a pretty through job! :wrench: There is a reason you don't have heat. We just need to find it. :) :safari: |
Originally Posted by old87yota
(Post 52420731)
I assume the line you capped off was only for the rear heater, right?
Does the cable that is supposed to open the water valve move the valve open and closed fully? Does the valve physically move open and closed (as in remove heater hoses and look at the inside of the valve)? Are you 100% sure there is no air in the heater core? Is there a lot of debris in the A/C or heater box under the dash? What is the ambient outdoor temperature? I am just trying to find a reason for the heater hoses to be hot but you are still not getting any heat. You seem to have done a pretty through job! :wrench: There is a reason you don't have heat. We just need to find it. :) :safari: I removed the valve and checked the operation to see that it opens fully as I looked through it. I installed it and operated the lever for the cable and verified it fully opened it as I can see clear through it with the hoses off. I'm not positive there is no air in the heater core, but I parked on a steep incline with the front uphill and use a Lisle Funnel that attaches to the radiator filler neck while it had 4 inches of coolant in it above the filler neck. Reved the engine many times squeezed hoses. I repeated this a few times over a few weeks so I hope that would have gotten any air out of the heater core. These is zero debris in the a/c or heater box, I removed the heater box from the vehicle when I replaced the heater core so I could operate the blend doors to make sure they were opening and closing properly to direct the air through the heater core. Outdoor temps have been from the teens into the 40s and it only put out heat for 30 seconds or so when I put the blower on then it blows cold. I've really done everything I can think so I'm open to any additional suggestions to get this working. I already started keeping my eye out for a used winter ride, which I really don't want to do, I want to fix this and not let it defeat me!!! |
Just covering bases since a lot of things were done to fix a seemingly frustrating problem.
You must be in a cold place this time of yr... 200 would be more like op temp. For some makes, the fan doesnt engage until after 210. All the heater hoses checked for restriction? New heater core is Toyota too right? You said you verified the blend doors...how exactly? Is it possible something is partially obstructing the cable mechanism or seized/worn? Funny it's mentioned that flushes were part of routine service but then the rad became blocked...some things aren't quite as they seem. I would suspect the blend doors, a restriction, or a leak somewhere, even though you mention that you verified. Please dont take offense as some here do. Its just difficult to try and help when we're physically unable to see it for ourselves. |
Originally Posted by pungojoe;52420582.[list
[*]With a Lisle radiator funnel and the front of the vehicle on uphill on a steep incline I burped the system by reving the engine and squeezing all the hoses. I think I was able to get all the air out. I then topped of the overflow and put a new cap on the radiator.[/list]
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Originally Posted by 75w90mantraN
(Post 52420736)
Just covering bases since a lot of things were done to fix a seemingly frustrating problem.
You must be in a cold place this time of yr... 200 would be more like op temp. For some makes, the fan doesnt engage until after 210. All the heater hoses checked for restriction? New heater core is Toyota too right? You said you verified the blend doors...how exactly? Is it possible something is partially obstructing the cable mechanism or seized/worn? Funny it's mentioned that flushes were part of routine service but then the rad became blocked...some things aren't quite as they seem. I would suspect the blend doors, a restriction, or a leak somewhere, even though you mention that you verified. Please dont take offense as some here do. Its just difficult to try and help when we're physically unable to see it for ourselves. I check both inlet and outlet heater hose by blowing into them and there was zero restrictions. The heater core is Toyota. I bought the vehicle with ~90k miles on it over 15 years ago, so I don't know the history of flushes prior to that. I use it mostly for shorter trips, but I was on the highway doing 70+ mph for ew hours, so it must have caused some particulates to come loose and clog up the radiator. Looking the my flush history, I never went past 4 years without a flush, and several of those were not a flush but a drain and fill since there fluid was clean. Maybe I should have performed more chemical flushes? The blend doors were easy to see operate properly when I had the heater box out. Both doors are connected with a rod so they work in unison. The cable operates freely and moves the door. I check the cable adjustment per the manual. I did allot of checking of cable operation prior to replacing the heater core since that's what I was hoping the problem was since removing the heater core was not trivial. |
Originally Posted by 75w90mantraN
(Post 52420737)
Did you run the heater on full blast while burping out the air pockets? Not mentioned and worth clearing up.
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I run mine on high, but I dont see anywhere how fan speed relates to ridding out air.
My guess is with using strong solvents, maybe more crud got loosened up over the recent drive cycles and stuck somewhere in the lines. Thinking out in Jupiter, maybe the AC is on somehow, like shorted ON. Compressor isnt running hopefully... |
Have you removed the blower motor to see the blend air doors are moving properly to divert air to heater core or bypass, does your HVAC controls have the slider control or the dials.
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Originally Posted by Malcolm99
(Post 52420845)
Have you removed the blower motor to see the blend air doors are moving properly to divert air to heater core or bypass, does your HVAC controls have the slider control or the dials.
When I replaced the heater core, I had the entire heater box out, tested and verified the operation of the blend doors while I had it on the bench with the new heater core install. The blend door are operating perfectly. I have the slide controls not the dials, I verified the slide lever operates the blend doors and coolant control valve properly. I adjusted both cables per the shop manual and verified for smooth and easy operation. I even used a bore scope down the center air vent to watch the operation of the blend door, which it opened and closed properly when moving the hot/cold slide control.
Originally Posted by 75w90mantraN
(Post 52420790)
I run mine on high, but I dont see anywhere how fan speed relates to ridding out air.
My guess is with using strong solvents, maybe more crud got loosened up over the recent drive cycles and stuck somewhere in the lines. Thinking out in Jupiter, maybe the AC is on somehow, like shorted ON. Compressor isnt running hopefully... The A/C compressor is definitely not coming on. |
How is your coolant level? I had terrible heat as a precursor to my HG going in my ‘97. |
Originally Posted by fierohink
(Post 52420942)
How is your coolant level? I had terrible heat as a precursor to my HG going in my ‘97. Was your coolant level low when your HG went? |
It was eating coolant. I thought I had a leak at the water pump or possibly the rear heater lines. I would SLOWLY lose coolant. In hindsight it was probably the head gasket or possibly a water pump that gave out. I junked the truck because it had frame rot that I wasn’t going to deal with plus a HG. |
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