Fj80 overheating issue + more

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SciroccoDamonte

SciroccoDamonte

Joined
Jun 16, 2024
Threads
11
Messages
47
Location
eureka CA
Website
www.youtube.com
So my 1991 fj80 is having some pretty intense overheating issues, ill give an example. I was driving outside of redding CA on i5 going downhill at about 60 mph. It was about 90 degrees out. And the needle was almost in the red, this was with heaters full blast and windows all the way up. And going over buckhorn pass which is a long fairly steep grade. I was in second at about 20 mph or 2400rpm and the needle was full peg, but the truck wasnt dying or losing power. Over a previous pass the truck was really hot and the speedometer and odometer died (like cut out and just stopped working) and dont do anything at all. Any ideas?
 
Who cares about the gauge cluster when you’re gonna blow your engine? I would highly recommend getting your cooling system up to date and working properly. worry about anything else later.
 
Fj80oregon said:
Who cares about the gauge cluster when you’re gonna blow your engine? I would highly recommend getting your cooling system up to date and working properly. worry about anything else later.
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He's got another thread he started like 20 minutes later about his AC... I can't decide if he's trolling or just completely in over his head.
 
Fj80oregon said:
Who cares about the gauge cluster when you’re gonna blow your engine? I would highly recommend getting your cooling system up to date and working properly. worry about anything else later.
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Im not worried about the gauge cluster. No reason to be an ass. Im asking to see if anyone had a solution to the issue.
 
SciroccoDamonte said:
Im not worried about the gauge cluster. No reason to be an ass. Im asking to see if anyone had a solution to the issue.
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Was stressing the importance of you cooling system and your lack of acknowledging your engine overheating twice. That’s all if you take that as me being an ass that’s your problem. Good luck
 
SciroccoDamonte said:
So my 1991 fj80 is having some pretty intense overheating issues, ill give an example. I was driving outside of redding CA on i5 going downhill at about 60 mph. It was about 90 degrees out. And the needle was almost in the red, this was with heaters full blast and windows all the way up. And going over buckhorn pass which is a long fairly steep grade. I was in second at about 20 mph or 2400rpm and the needle was full peg, but the truck wasnt dying or losing power. Over a previous pass the truck was really hot and the speedometer and odometer died (like cut out and just stopped working) and dont do anything at all. Any ideas?
Click to expand...
My first idea is to stop driving it until you get the cooling system sorted out.
Give us some details on the vehicle history.
What maintenance has been done to the cooling system so far?
What maintenance has been done to the truck in general?
 
The gauge cluster failing is a sign of the AC failing, as when the AC clutch seizes up. So it's relevant here, if not the most important thing needing addressed.
 
jonheld said:
My first idea is to stop driving it until you get the cooling system sorted out.
Give us some details on the vehicle history.
What maintenance has been done to the cooling system so far?
What maintenance has been done to the truck in general?
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The truck is fine everywhere else except hills and i guess temperatures over 90 degrees. The truck has been meticulously maintained for most of its life. In my time of owning it, the thermostat housing gasket went out, which I replaced. The radiator is two years old, the water pump is 5 years old. And its had all new hoses in the past few years. Thats all that i can remember.
 
The Toyota temperature gauges are notoriously slow to respond to an overheating situation.

If the needle hits the red, chances are you've already done damage to head, head gasket etc

BUT verifying the coolant temperature would be a good idea.

You can buy an infrared temperature gun cheap enough to have one in the truck. If the gauge moves above normal, stop take temperature readings at the top radiator hose.

Or install a Watchdog temperature monitor or similar so you have a reliable readout on temperature.

You don't mention the engine fan clutch in your list of maintenance items.
This is often overlooked, and having a fully functional fan clutch seems to be the number 1 thing that solves overheating issues.
 
SciroccoDamonte said:
The truck is fine everywhere else except hills and i guess temperatures over 90 degrees. The truck has been meticulously maintained for most of its life. In my time of owning it, the thermostat housing gasket went out, which I replaced. The radiator is two years old, the water pump is 5 years old. And its had all new hoses in the past few years. Thats all that i can remember.
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As stated, the fan clutch is often overlooked when addressing cooling system issues. You want an Aisin FCT-049 for the 3FE.
DO NOT USE AFTERMARKET PARTS ON THIS MOTOR.
Also be certain the fan shroud is in place and is in 1 piece and tight to the radiator.

There are several cooling system related threads with good information. Search is your friend.
 
jonheld said:
As stated, the fan clutch is often overlooked when addressing cooling system issues. You want an Aisin FCT-049 for the 3FE.
DO NOT USE AFTERMARKET PARTS ON THIS MOTOR.
Also be certain the fan shroud is in place and is in 1 piece and tight to the radiator.

There are several cooling system related threads with good information. Search is your friend.
Click to expand...
Yea fan clutch is definitely something im gonna check. Thanks for the suggestion
 
mudgudgeon said:
The Toyota temperature gauges are notoriously slow to respond to an overheating situation.

If the needle hits the red, chances are you've already done damage to head, head gasket etc

BUT verifying the coolant temperature would be a good idea.

You can buy an infrared temperature gun cheap enough to have one in the truck. If the gauge moves above normal, stop take temperature readings at the top radiator hose.

Or install a Watchdog temperature monitor or similar so you have a reliable readout on temperature.

You don't mention the engine fan clutch in your list of maintenance items.
This is often overlooked, and having a fully functional fan clutch seems to be the number 1 thing that solves overheating issues.
Click to expand...
Thats a good idea, one of my suspects is that my gauge is incorrect, as the vehicle rises to operating temperatures quickly. Fan clutch is the first on my list. Thank you.
 
I doubt your gauge is incorrect. By design, they are really only a dummy gauge. The middle point of the needle does not represent a specific number, it represents a temperature range. I don't know the specifics for the 3FE, but on the 1FZ in the later 80 series, needle in the middle is something like 160-220, while normal operating temperature is around 190. Point being, your needle hits the middle before it's at full operating temperature, and by design it's normal for your engine to warm up quickly, and then the cooling system keeps it there. If you are often running close to red, it sounds like you are always running on the verge of overheating, thus it doesn't take much to push it into the red. I agree with fan clutch and anything else that needs to be done. Good luck, and of course report back
 
SpenserAK said:
I doubt your gauge is incorrect. By design, they are really only a dummy gauge. The middle point of the needle does not represent a specific number, it represents a temperature range. I don't know the specifics for the 3FE, but on the 1FZ in the later 80 series, needle in the middle is something like 160-220, while normal operating temperature is around 190. Point being, your needle hits the middle before it's at full operating temperature, and by design it's normal for your engine to warm up quickly, and then the cooling system keeps it there. If you are often running close to red, it sounds like you are always running on the verge of overheating, thus it doesn't take much to push it into the red. I agree with fan clutch and anything else that needs to be done. Good luck, and of course report back
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The thing is in stays in the exact middle, even slightly below all around town. It only overheats when the temperature outside is above 60-70. Its almost like the sun beating down on the truck disables the entire cooling system. I have a working theory that the timing is off slightly. It has a rough idle but that goes away above 1000rpm
 
SciroccoDamonte said:
The thing is in stays in the exact middle, even slightly below all around town. It only overheats when the temperature outside is above 60-70. Its almost like the sun beating down on the truck disables the entire cooling system. I have a working theory that the timing is off slightly. It has a rough idle but that goes away above 1000rpm
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Rough idle is almost always due to unmetered air entering the system. The top half of the motor wants to be air tight.
Have a look at the 3FE tune up guide in the resources section.
 
SciroccoDamonte said:
The thing is in stays in the exact middle, even slightly below all around town. It only overheats when the temperature outside is above 60-70. Its almost like the sun beating down on the truck disables the entire cooling system. I have a working theory that the timing is off slightly. It has a rough idle but that goes away above 1000rpm
Click to expand...
Fan clutch, seriously. In colder temps, your system doesn't need the help. I hope you haven't done any damage, but you need to get this issue worked out before you keep driving it to troubleshoot things like rough idle.
 
The speedometer and odometer are unrelated to the overheating issues.
The 91-92 version is a cable driven unit.

Also check your belt tension because loose belts will cause low charging and may not allow the water pump to circulate the coolant like it should. Maybe you need new belts. Use Toyota belts, as they are less expensive than aftermarket and they are the correct fit.

These typically require very tight belts. More than you are used to using on other makes.
 
Thank you guys for the help, ive got a list of stuff to get started on. I did the test where you get the truck hot then test to see the resistance on the fan clutch and there was absolutely none, almost free spinning. Needless to say I ordered the fan clutch, regardless of that test. I will report back when ive got more things checked off.
 
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