cj80cruiser
Senior Member
That one he had posted will come in as KoyoRad.
Overheating again...
- Thread starter Atreyus
- Start date
That one he had posted will come in as KoyoRad.
Atreyus
New member
So I just changed out the radiator, drove for about an hour, 30 miles stop and go traffic and on the freeway, with A/C on full blast and so far no over heating. Needle is below the half way point a little bit, where it should be I guess. I'll update this again within a week about my progress. so far so good.
Atreyus
New member
I spent $110 got a radiator brand new from a reputable guy my friend referred me to. Took about an hour for me and my brother to install, but it was our first time installing a new radiator on my truck. It seems to shift a lot smoother, why? I have no idea lol but I like that while driving. I wanna do the cooler also, but hopefully I can find someone to help me do that as I would be afraid to do it myself lol.
Armygrunt11
New member
Overheating Issue
I have a 1999 Toyota 4Runner. It's overheating when a thermostat installed.
Back story. The head gasket blew a few years ago. My brother got the head resurfaced and we installed a new head gasket. After putting everything back together it would overheat with the thermostat installed. Over heat just running idol. I've installed 7 different thermostats, a new water pump, new radiator, and even installed a electric fan to take some extra stress of the engine. There is no combustible fluid in the coolant. So I'm stuck. Any idea's what is causing this?
It currently has 201,000 miles on it. I'm about to cut my losses, but I've put so much money in it so far I just want to fix this. Any help is appreciated.
I have a 1999 Toyota 4Runner. It's overheating when a thermostat installed.
Back story. The head gasket blew a few years ago. My brother got the head resurfaced and we installed a new head gasket. After putting everything back together it would overheat with the thermostat installed. Over heat just running idol. I've installed 7 different thermostats, a new water pump, new radiator, and even installed a electric fan to take some extra stress of the engine. There is no combustible fluid in the coolant. So I'm stuck. Any idea's what is causing this?
It currently has 201,000 miles on it. I'm about to cut my losses, but I've put so much money in it so far I just want to fix this. Any help is appreciated.
Can you report the temperatures on the upper radiator hose (top water outlet on engine) and lower at operating temperature (T-stat housing)?
Do you have anything installed to obstruct the air flow in front of the AC condenser?
When did you last cleaned the AC condenser fins? In your area, bugs is a big issue (I lived in Louisiana). A drive in the night in summer gets lots of bugs to clog the AC condenser.
Is your waterpump Aisin or OEM?
Quality of the fan clutch? After turning off the engine, do you see the fan is spinning several rounds before coming to a stop?
Do you have anything installed to obstruct the air flow in front of the AC condenser?
When did you last cleaned the AC condenser fins? In your area, bugs is a big issue (I lived in Louisiana). A drive in the night in summer gets lots of bugs to clog the AC condenser.
Is your waterpump Aisin or OEM?
Quality of the fan clutch? After turning off the engine, do you see the fan is spinning several rounds before coming to a stop?
Armygrunt11
New member
When I did have the thermostat in the top hose was hot and the bottom hose was warm. Idk the exact temp though.
Everything is stock, so nothing is blocking the a/c condenser.
I haven't tried cleaning the condenser fins yet though.
The water pump is OEM. The old one still looked good to, but I replaced it anyway just because I was already there.
I took the clutch Fan off and installed a electric fan. This does help keep it from over heating when I'm stuck at in stand still in traffic. When before it would overheat. The clutch fan stopped spinning when I cut off the engine when it was installed.
Everything is stock, so nothing is blocking the a/c condenser.
I haven't tried cleaning the condenser fins yet though.
The water pump is OEM. The old one still looked good to, but I replaced it anyway just because I was already there.
I took the clutch Fan off and installed a electric fan. This does help keep it from over heating when I'm stuck at in stand still in traffic. When before it would overheat. The clutch fan stopped spinning when I cut off the engine when it was installed.
StreetCreeper
New member
I would put a new OEM Asin fan clutch back in there.
Looking at about $100 on Amazon.
You should not need an extra fan to keep from overheating in traffic. If you are over heating in traffic — there is a good reason for it.
The Asin fan is more than sufficient to prevent your engine from overheating in normal stop & go traffic provided the rest of your cooling system is functioning properly.
As streetcreeper said get a new aisin fan clutch or rebuild your current one.
If an electric fan helped it sounds like the original aisin fan clutch wasn't working properly.
It's also critical to have the fan shroud in place.
There is a test somewhere here for the aisin fan clutch.
Here's a quick test
Try the following (by hand):
Engine cold: Spins with difficulty (with engine off), fan roars at start up
Engine warm: Fan spins freely by hand
Engine hot: Fan will not spin (with engine off) and fan roars as idle is increased
If an electric fan helped it sounds like the original aisin fan clutch wasn't working properly.
It's also critical to have the fan shroud in place.
There is a test somewhere here for the aisin fan clutch.
Here's a quick test
Try the following (by hand):
Engine cold: Spins with difficulty (with engine off), fan roars at start up
Engine warm: Fan spins freely by hand
Engine hot: Fan will not spin (with engine off) and fan roars as idle is increased
Last edited:
mtbtim
Elite Member
I made a video of testing my fan clutch and replacing it. I think my fan clutch was still able to do it's job but there were two tests that told me my fan clutch was getting tired.
#1) When my rig was at operating temperature, around 190-192 degrees, I turned off the motor to see if the fan would come to an almost immediate stop. It did not and pinwheeled a little bit before coming to a stop.
#2) Now that the motor was off, I then checked to see if the fan clutch was showing signs of being locked up by trying to spin the fan. I was able to spin the fan and watch it pinwheel around and around. A healthy fan clutch that should be locked up because the engine was at operating temperature would have lots of resistance and shouldn't spin like that.
After I installed the new Aisin fan clutch, I repeated the above tests and the fan came to an immediate stop when I turned the motor off and I could not spin the fan by hand making it pinwheel after the motor was turned off. So, I concluded my fan clutch was getting tired and replacing it was a good decision.
Here's the video. Hope it helps you out.
<iframe width="560" height="315" src="https://www.youtube.com/embed/WzhlACxqeqQ" frameborder="0" allowfullscreen></iframe>
#1) When my rig was at operating temperature, around 190-192 degrees, I turned off the motor to see if the fan would come to an almost immediate stop. It did not and pinwheeled a little bit before coming to a stop.
#2) Now that the motor was off, I then checked to see if the fan clutch was showing signs of being locked up by trying to spin the fan. I was able to spin the fan and watch it pinwheel around and around. A healthy fan clutch that should be locked up because the engine was at operating temperature would have lots of resistance and shouldn't spin like that.
After I installed the new Aisin fan clutch, I repeated the above tests and the fan came to an immediate stop when I turned the motor off and I could not spin the fan by hand making it pinwheel after the motor was turned off. So, I concluded my fan clutch was getting tired and replacing it was a good decision.
Here's the video. Hope it helps you out.
<iframe width="560" height="315" src="https://www.youtube.com/embed/WzhlACxqeqQ" frameborder="0" allowfullscreen></iframe>
Ehahn84
New member
Mine was leaking from the heater control valve by the firewall. It was just dripping, but enough to lower the coolant over about a week or so. Changed it out and no loss of coolant or anything. I too replaced my thermostat, water pump, radiator, etc. and it ended up being this.
Armygrunt11
New member
I appreciate all the help. I'll follow up once I've checked these.
thegipper
New member
Did any of you guys that had the leak by the heater control valve notice coolant on the ground? I would think if it was leaking from there, you would be seeing it on the ground to some extent.
kball
New member
Is this a 4 or 6 cyl? I have no experience doing head gaskets on these but from what I've read it's easy on the 6 cyl engines to get the gaskets on the wrong side or upside down so they block coolant passages. There should be a tab that sticks out from the sides that you can real L or R I think. Make sure they are oriented correctly. If it's a 4 cyl, I don't know. Maybe those are also capable of being put on wrong and block passages.
kball
New member
Ehahn84
New member
Sorry for the late response. No, I didn't get any coolant accumulation on the ground.
What do you mean by overheating?
You can test the thermostat by removing it and doing a stove top test (place small pot of water on stove with thermostat in the water, when the water begins to boil, use tongs to remove it and check to see if it opened up). Also, while thermostat is out of vehicle, run the engine and see if you still have a hot/cold hose situation. That would be an easy way to narrow down where the problem is generally.
I've bought new thermostats before that failed, it's not that common, but still exists.
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