Luke warm heat?

R

Rebel4Runner

New member
Good morning everyone and happy Monday, that being said it is unfortunately Monday and time to go back to the daily routine.

Ok fellas I need help I just purchased a 1998 4runner with the V6 engine. What I have noticed is it takes forever to warm the engine up or at least to blow hot air. Also my temp gauge does no appear to be working at all it rest beneath of the C.

Any help would be greatly appreciated I am new to doing my own repairs but learn quickly and enjoying fixing things myself. I just need wisdom from all you guys that know what your doing.
 
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First thing, when the engine is cool, check the coolant level.
Next, after driving, see if the top of the radiator is hot and also the bottom.
You could also have a stuck open thermostat.
 
ok well the radiator is full with the overflow as well. I am thinking it is the thermostat. But want to make sure that is what it could be. Have you guys heard about the heater core being clogged?
 
Rebel4Runner said:
ok well the radiator is full with the overflow as well. I am thinking it is the thermostat. But want to make sure that is what it could be. Have you guys heard about the heater core being clogged?
Click to expand...

I've seen heater cores become clogged when they fail. They will begin to leak coolant and that coolant will 'crystallize' causing it to clog. However, I would start with the problem of the truck not warming up. Definitely sounds like a bad/nonexistent thermostat. I've seen individuals remove their thermostat entirely if they have overheating issues, hopefully yours is just a failed thermostat. Once that problem is resolved, do a proper coolant bleed with the heat on full to bleed the heater core. Hopefully by doing that you will have heat restored.

Max
 
If the radiator is hot and still no heat, possible clogged heater core.
If the radiator is cool, probably the thermostat.
The thermostat could be stuck wide open and the coolant is flowing un-restricted and the radiator is cooling it faster than the engine can get it hot.

The radiator cap probably isn't bad, usual signs would be overheating without reaching normal operating temperature.

Do you have a rear seat heater?
If so, crank it up and see if that air is hotter than the front heater.

Do you know anyone with a Scangauge or Ultragauge?
Plugging this in would show engine temps. If you get no reading or no change in reading, the temp sensor on the engine is probably bad.

You have two symptoms that may be due to the same thing or completely separate. You need to link or separate them.
 
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Well I'm getting heat it just takes a really long time to get it, and when I do its still not hot like its supposed to do. And as far as the rear heater it blows colder than the front. The temp gauge is practically nonexistent it doesn't work.
 
Rebel4Runner said:
ok well the radiator is full with the overflow as well. I am thinking it is the thermostat. But want to make sure that is what it could be. Have you guys heard about the heater core being clogged?
Click to expand...

I would not think it's the core if the engine is not coming up to temp.
Does the rear heater work?
 
x2 on Stuck open t-stat or no t-stat at all
its most likely not a clogged heater core but an easy test is to check whether or not the heater core inlet hose is hot/warm if the outlet hose is cold then you know its clogged. Get it fixed its not good to be running the engine that cool
 
We still don't know if the radiator is getting hot when you don't have heat.
There is a procedure for checking if the temp sensor is working too.
 
Ok so i have an update on my issue here i want to thank everyone who has been helping me with this issue so far.

Ok so

1. Radiator is full
2. Heater control Valve works
3. Radiator hose coming from top of radiator is hot, while hose on bottom was warm.
4. The radiator itself was warm
5. My dash temp reading shows below the C but when sitting still reving the engine to say around 2000 to 2500 rpm the temp gauge will rise and the heat gets warmer and warmer.
5. So i'm thinking that the thermostat gets stuck open while i'm driving or is not opening up all the way in general (my thinking being that say the engine gets slightly warm it will be easier to heat the air while i'm not moving). So i'm just going to replace the thermostat.
6. I called autozone they have 2 in stock one is 10.99 for a standard one or a failsafe one for 17.99 money aint an issue here what do you guys think?
 
Radiator hose coming from top of radiator is hot, while hose on bottom was warm. The radiator itself was warm.
All normal. This is good. The radiators do a great job of cooling (maybe too well in your case). I have been in 105* summer and the lower radiator hose was barely warm. The thermostat is constantly opening and closing to regulate the proper running temperature. It also sounds like the waterpump is working.

It sounds like two issues. Bad thermostat and probably the temp sensor is bad.

The failsafe unit will fail open if it fails allowing the engine to not overheat from a failed thermostat.
 
Seems like the fail safe is the right way to go. I wonder how hard it would be to fix the temp gauge i am not a fan of taking the dash out.
 
The temp gauge might fix itself once you get a good heat rolling out the heater.
Sounds like you have a fail safe thermostat currently installed that failed.
 
Grenvilleter said:
The temp gauge might fix itself once you get a good heat rolling out the heater.
Sounds like you have a fail safe thermostat currently installed that failed.
Click to expand...

Yeah no joke, hopefully changing the thermostat will fix my issues. We will see i think i will change it this weekend so if i mess something up i will have time to work on it.
 
Its probably not the guage. Your temp sensor is different then the guage in your dash and would be easy to change. The temp sensor sends the temp to the temp guage in your gauge cluster. This sensor is also located in the engine compartment. No guage cluster work necessary.
 
RdRunNNeR said:
Its probably not the guage. Your temp sensor is different then the guage in your dash and would be easy to change. The temp sensor sends the temp to the temp guage in your gauge cluster. This sensor is also located in the engine compartment. No guage cluster work necessary.
Click to expand...

Ok well that is good to know have any of you had to change your thermostat on the 3.4L v6. It doesn't look fun to me
 
The gauge just reads what it gets from the temp sensor.
It has no control over the actual temp.
Still leaning towards thermostat.
 
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