Unas2k5
Well-Known Member
- Thread starter
- #1
Hey everyone,
I’m trying to diagnose an overheating issue before I start replacing more parts, and I wanted to get some opinions from people who have seen this before.
Car:
* 2015 Mustang GT 5.0
* ProCharger Stage 2
* Around 850+ hp
* Mishimoto 160° thermostat (about 3 years old)
* Stock/base GT radiator (not Performance Pack)
Symptoms:
* On cooler days (70-80°F), the car runs pretty well. Driving home yesterday in the 70s, my CHT never even reached 200°F.
* On hot days (90°F+), especially in traffic or after idling, my Cylinder Head Temperature climbs into the 240-250°F range, which obviously concerns me.
* Lund Racing told me this is not tune-related. They said my tune already commands the fans on earlier than stock and suggested checking the thermostat, water pump, fans, or a possible air pocket.
Today I used my Autel IM508 with the engine OFF (cold engine) to run active tests on the cooling fans.
Results:
* High-speed fan test: Only the driver-side fan comes on. The passenger-side fan does nothing.
* Low-speed fan test: Neither fan comes on, although I can hear a relay clicking when I command the test.
Before I start replacing parts, I’m trying to figure out what this points to.
Questions:
1. On a 2015 GT, should both fans run during the high-speed active test?
2. Does this sound like a failed passenger-side fan motor, a fan control module issue, wiring, or something else?
3. Could having only one fan operating explain why the car is fine in 70-80°F weather but gets into the 240-250°F CHT range once ambient temperatures are above 90°F?
4. Since I already have a brand-new Reische 170° thermostat, would you replace that first, or would you diagnose the fan issue before touching the thermostat?
5. Any fan upgrades better than stock?
Any advice would be appreciated. Thanks!
I’m trying to diagnose an overheating issue before I start replacing more parts, and I wanted to get some opinions from people who have seen this before.
Car:
* 2015 Mustang GT 5.0
* ProCharger Stage 2
* Around 850+ hp
* Mishimoto 160° thermostat (about 3 years old)
* Stock/base GT radiator (not Performance Pack)
Symptoms:
* On cooler days (70-80°F), the car runs pretty well. Driving home yesterday in the 70s, my CHT never even reached 200°F.
* On hot days (90°F+), especially in traffic or after idling, my Cylinder Head Temperature climbs into the 240-250°F range, which obviously concerns me.
* Lund Racing told me this is not tune-related. They said my tune already commands the fans on earlier than stock and suggested checking the thermostat, water pump, fans, or a possible air pocket.
Today I used my Autel IM508 with the engine OFF (cold engine) to run active tests on the cooling fans.
Results:
* High-speed fan test: Only the driver-side fan comes on. The passenger-side fan does nothing.
* Low-speed fan test: Neither fan comes on, although I can hear a relay clicking when I command the test.
Before I start replacing parts, I’m trying to figure out what this points to.
Questions:
1. On a 2015 GT, should both fans run during the high-speed active test?
2. Does this sound like a failed passenger-side fan motor, a fan control module issue, wiring, or something else?
3. Could having only one fan operating explain why the car is fine in 70-80°F weather but gets into the 240-250°F CHT range once ambient temperatures are above 90°F?
4. Since I already have a brand-new Reische 170° thermostat, would you replace that first, or would you diagnose the fan issue before touching the thermostat?
5. Any fan upgrades better than stock?
Any advice would be appreciated. Thanks!
Sponsored
