P500 P520 overheating - Help needed

A

ALCONN

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Apr 28, 2025
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Hi All

My 2021 P520 recently started to overheat although the temp gauge on the dash only shows 2 bars
I know it was overheating because the seat got rather warm
I also noticed that the cooling fan wasn't coming on as usual
Check the fan fuse and it was fine
I thought it could be the temp sensor and when I unplugged it with the key on the fan comes on ??
Ordered a new sensor and same issue continues
2 bars on the gauge and engine getting hot, fan doesn't come on unless I unplug the temp sensor
HELP
Please and Thank you
 
trigger

trigger

Old Ironsides
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Hi All

My 2021 P520 recently started to overheat although the temp gauge on the dash only shows 2 bars
I know it was overheating because the seat got rather warm
I also noticed that the cooling fan wasn't coming on as usual
Check the fan fuse and it was fine
I thought it could be the temp sensor and when I unplugged it with the key on the fan comes on ??
Ordered a new sensor and same issue continues
2 bars on the gauge and engine getting hot, fan doesn't come on unless I unplug the temp sensor
HELP
Please and Thank you
Well the seat getting hot is normal unless you have some type of shielding. Is it spitting antifreeze? I understand questioning when the fan comes on but how do you know you're overheating?
 
Dan Lawrie

Dan Lawrie

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Nov 11, 2024
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Las Vegas, NV
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  1. 520
Hi All

My 2021 P520 recently started to overheat although the temp gauge on the dash only shows 2 bars
I know it was overheating because the seat got rather warm
I also noticed that the cooling fan wasn't coming on as usual
Check the fan fuse and it was fine
I thought it could be the temp sensor and when I unplugged it with the key on the fan comes on ??
Ordered a new sensor and same issue continues
2 bars on the gauge and engine getting hot, fan doesn't come on unless I unplug the temp sensor
HELP
Please and Thank you
I live in vegas and my p520 always runs with 2 bars. If you look under the buggy you will see the exhaust loops just inches below the seatbelts. That's why I put in a heat shield above this exhaust loop. It has made a huge difference my butt nolonger frys on our daily rides. My fan doesn't go on that often either but I don't think it's a problem. I would check your anti freeze / coolant. Maybe it's too much water not enough coolant.
 
A

ALCONN

New Member
Apr 28, 2025
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Ontario, Canada
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  1. 520
Thanks Dan
Perhaps you are correct it just feels a lot hotter than before and used to hear the fan every so often
Any Idea what the engine temp should read at the cylinder head if I hit it with an infrared thermometer
would love to know and confirm everything is ok

Appreciate the response
 
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A

ALCONN

New Member
Apr 28, 2025
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Ontario, Canada
Ownership

  1. 520
Well the seat getting hot is normal unless you have some type of shielding. Is it spitting antifreeze? I understand questioning when the fan comes on but how do you know you're overheating?
Hi Trigger

Just feels a lot hotter than I felt before - Not spitting antifreeze
Havent heard the fan run and used to every so often
Maybe paranoia but dont want to cook the engine

Any Idea what the engine temp should be if I read it with a infrared thermometer at the cylinder head ?

Thank you
 
Hello_Darkness

Hello_Darkness

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The fan should come on when the sensor us unplugged, it's a failsafe since the PCM assumes it doesn't know the actual temperature.

With the sensor unplugged, it thinks the coolant is -40 F and sees the IAT sensor isn't that temperature and turns the fan on to keep from overheating.

Fan doesn't come on until around 215-220 or so I believe.

If the system wasn't working, the gauge would hit 3 bars and then start puking coolant
 
H

hondabob

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If you run WOT in deep loose sand for about 15 miles you can get it hot enough to have the 3rd bar to come on. I drove it easy for a few minutes, and it went back to 2 bars. After a minute or two hot soak you can get the 3rd bar to come on for about 20 seconds on the hot start up. Same with the other Pioneers and Talons.
 
Dan Lawrie

Dan Lawrie

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Nov 11, 2024
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Las Vegas, NV
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Thanks Dan
Perhaps you are correct it just feels a lot hotter than before and used to hear the fan every so often
Any Idea what the engine temp should read at the cylinder head if I hit it with an infrared thermometer
would love to know and confirm everything is ok

Appreciate the response
I don't know I've never checked it.
 
The Green Goat

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I've had mine to 5 bars with the overtemp light on, but it's because I had a radiator plugged with mud.

Rinse the hell out of yours from all angles until the water runs clear. Then, spray the fins down with foaming coil cleaner (like for an HVAC condenser; found at Home depot). Let it sit for 10 minutes, then rinse again. Do this a few times until you don't get anymore crud out.
 
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DRZRon1

DRZRon1

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Hi Trigger

Just feels a lot hotter than I felt before - Not spitting antifreeze
Havent heard the fan run and used to every so often
Maybe paranoia but dont want to cook the engine

Any Idea what the engine temp should be if I read it with a infrared thermometer at the cylinder head ?

Thank you
I’d check temp at the fitting at the top and bottom of radiator as well as just grab the radiator hoses😂.

If it’s circulating water, fan runs in right direction, filled with coolant, not puking coolant out, clean radiator, thermostat opens - it’s fine.
 
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A

ALCONN

New Member
Apr 28, 2025
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4
3
Ontario, Canada
Ownership

  1. 520
The fan should come on when the sensor us unplugged, it's a failsafe since the PCM assumes it doesn't know the actual temperature.

With the sensor unplugged, it thinks the coolant is -40 F and sees the IAT sensor isn't that temperature and turns the fan on to keep from overheating.

Fan doesn't come on until around 215-220 or so I believe.

If the system wasn't working, the gauge would hit 3 bars and then start puking coolant
Thank you

I appreciate the feedback

Think Im good then, just paranoid :D