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1994 pickup - 22re - radiator fan is always on - wtf
Someone please help.
I have a 1994 toyota pickup. 22re.
When I turn the engine on, the radiator fan turns on, and stays on. It never turns off unless I turn the engine off. (I mean the fan that is attached to the radiator which blows air on to the radiator).
So the temp gauge inside the truck never reaches full operating temp. It stays a hair above the C mark. Is it bad to drive it around like this? Will the radiator fan burn out if its always on like this?
After some research, I read that the "coolant temp sensor" can go bad, and either; it will crap out where the fan is on all the time, or, it will crap out where the fan never comes on.
See image of arrow pointing to the sensor I replaced. (internet image. not my truck. but same sensor stuff)
This made sense to me... so I went to pep-boys. Got a new coolant temp sensor. Replaced it. Super easy. Then restarted the truck. The fan is still coming on. WTF.
So, I unplugged the battery for 5 mins thinking the ECU maybe needs to reset. Nope that didn't do it either.
So, I'm at a loss. What should I try next?
I read somewhere, someone mentioned the radiator fan may have a relay in the fuse box in the engine bay. I def don't see anything specific to the radiator fan. I pulled a handful of the fuses just to check and they all seem good and have continuity through them.
Does the 94 have any fuse specific to the radiator fan?
See image. Are any of these fuses specific to the radiator fan?
What should I try next?
The truck is really clean and does not look molested in any way. I was thinking maybe someone hard-wired it to come on all the time, but the truck is clean and seems all stock.
From the factory, the 22RE engine has a mechanical cooling fan with a fluid clutch mechanism that is driven off of the water pump. In other words, the fan is always spinning to some degree and has no electrical connection.
From another post from BigBluePile a while ago:
No the fan always spins. It's just at temperature is when it reengages and you get the wwwWWWHIRR sound(and on startup).
and from the same post from TOYOTA 1:
No it spins whenever the engine is turning, but when the fan is not needed the clutches engage only partially. but when needed the fan clutch engages fully and keeps the fan spinning at the same rate (or close) as the motor.
When a clutch fan is going bad, the fan will either never engage fully(and can cause overheating). Or it can be stuck fully engaged(and can cool the motor too much).
Do you still have the stock mechanical fan or an aftermarket electric fan?
Have you verified that the engine is actually running cool?
There are a few possibilities that could contribute to an over cooling problem:
Stuck / bad fan clutch
Stuck open thermostat
Missing thermostat
The gauge is faulty or the electrical connection to the gauge is faulty and your truck is running normally
As far as I know, one of the coolant temperature sensors is for the gauge in your dash and the other is for the computer for air/ fuel mixture.
Thank you for the response.
Yes, the truck is new to me.
Seems to run awesome except for over-cooling.
It is all stock, including the stock OEM radiator fan.
To make sure I understand...
So, the fan on the radiator will always be spinning? but it is not "engaged to cool the radiator" until the "coolant-temp-sensor" tells the ECU to "fully engage the fan"?
Or, is it the water pump, mechanically that tells the radiator fan to fully engage?
I guess I'm still a little confused on what actually tells the fan to fully engage?
Also, the fan should not be fully engaged at all on startup right? Mine definitely is.
Based on your response it seems that maybe my clutch-fan is going bad and its always engaged?
Yes, I have verified the motor is not reaching full operating temp because the gauge on the dash never sits in the middle. The needle sits a hair above the "C" mark. Even on the highway. Which, this makes sense to me because the radiator fan is definitely fully engaged always.
So, what should I do now?
What do you guys think?
Anyway I can verify if it is indeed the fan-clutch? Cheap / easy to replace?
The fan SHOULD spin at start up and is engaged for a few seconds after startup then should "disengage" (but the fan still spins, it is just "idling"). Fan should be visibly spinning all the time the engine is running. I am not totally sure, but I think that the fan clutch has a bimetallic strip along with the fluid inside that tells the clutch to engage or disengage. I think it works off of the same principle as a cheap outdoor dial thermometer.
The strip expands as the temperature around the clutch rises.
I admit that I am not entirely sure how it works as I have never had a problem with mine.
It is purely mechanical and is NOT controlled by the ECU. This same fan set up is on my 22R carbureted engine which does not have an ECU.
What I meant by verifying that it is actually not reaching operating temperature is testing to see if your gauge in your dash is giving you a correct reading. After 20+ years, your gauge or the wiring could have a problem giving you an incorrect reading.
The best way to test this is with an infrared thermometer. The coolant temp should be around 180-190 degrees when the thermostat opens.
If the truck is actually not reaching operating temperature, I would definitely replace the thermostat first because the thermostat has control of when the coolant is allowed to circulate into the radiator.
They are fairly cheap from the dealership.
I hope I cleared some things up and did not confuse you more.
On initial start-up, the radiator fan is fully engaged.
After a few mins of driving, it's def still spinning, but it is not fully engaged.
I was wrong.
So, it is not fully engaged all the time.
I replaced the thermostat, and the temperature gauge sits slightly higher than before.
See the below image.
This is the highest I have ever seen the temperature since replacing the coolant-temp-sensor and also replacing the thermostat.
Normally the temp sits slightly lower than this.
I even had the truck idling in my driveway for 20 mins, while periodically revving the engine... and still the gauge sits a hair lower than what is seen in the below image.
Just so you know, these Toyota coolant temp gauges typically go to about 1/3 of the way up the gauge starting from cold for normal operating temperature. On my truck (1987 pickup) the gauge sits about 1/3 up the gauge.
Your gauge seems low to me but you could be fine.
Maybe someone who has a 1989-1995 truck could comment about the newer style gauge that you have and how their gauge looks.
Theses Toyota gauges are not the most accurate to begin with. Some gauges read higher, some lower for the same operating temperature. They are really there to tell you if your engine is overheating or not.
From your update description, it sounds like the fan is working correctly.
I would still try to use an infrared thermometer and point it around the thermostat and upper radiator hose to see if you are actually reaching operating temperature. You can buy one at Harbor Freight.
How is your gas mileage?
If you are getting good mileage, the engine runs well and you have checked the coolant temperature with an IR thermometer, you are probably fine.
03-04-2016, 05:44 PM
