I have a 2014 GSR with 60k miles and I ran into a problem in June and haven't had time to do much troubleshooting. I drove the car around 20 miles to/from a restaurant, and when I got home, I could hear the coolant boiling.

It was only around 75°F that evening, and my temp gauge never went above the normal operating temperature, but obviously the coolant got hot. When I checked the temp, it said 208°F for the coolant, meaning it definitely got above boiling temps.

So my first thought was a stuck thermostat. Swapped it out, no luck. Even tested the oem one by throwing it in some hot water, and it opened/closed perfectly fine.

Second thought was fuses. 40A fuse for rad fans is perfectly fine.

So my next step was to kick on the AC, and the fans turned on perfectly fine. I drove it 5 miles and parked it, and when I turned the car off, the radiator fans kicked on for about 30 seconds, then shut off on their own.


Sp the fans aren't dead, fuses are fine. My next step was to turn it on and pull the plug on the coolant temp sensor that's on the thermostat housing. Fans kicked on, but then again so did my CEL saying my car was overheating (since it couldn't read it).

Is there anything else I should check before buying a replacement water temp sensor that goes on the thermostat housing?


In the middle of trying to finish my tune and can't do anything til the temps are under control.

Thanks for reading, and I appreciate any ideas you can throw at me.
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It sounds like you've already done a good amount of troubleshooting, but there are a few more things you could consider checking before replacing the water temperature sensor:

1. **Wiring and Connections:** Ensure that the wiring and connections to the water temperature sensor are in good condition. Sometimes, a loose or damaged connection can cause inaccurate readings or intermittent issues.

2. **Cooling System Pressure Test:** Perform a cooling system pressure test to check for any leaks. Even a small coolant leak could lead to overheating. Make sure the system is holding pressure as it should.

3. **Coolant Level and Quality:** Verify that your coolant level is at the proper level and that the coolant mixture is correct. An improper coolant mixture can affect the boiling point and cooling efficiency.

4. **Air Pocket:** There could be an air pocket trapped in the cooling system that's causing circulation issues. Bleed the cooling system to ensure all air is removed.

5. **Radiator Cap:** Check the condition of your radiator cap. A faulty cap can cause coolant to boil at a lower temperature than normal.

6. **Water Pump:** While less common, a failing water pump could lead to insufficient coolant circulation and overheating. Check for any signs of coolant leakage from the water pump.

If you've ruled out these factors and the issue persists, then replacing the water temperature sensor might be a logical next step. Additionally, if your car is undergoing a tune, consider consulting with a mechanic or tuner who has experience with your specific model. They might be able to provide insights based on their expertise.

 

I appreciate the info!

I've also checked as much of the wiring as I can see under the hood. Haven't lifted it to check anything under yet. Coolant levels are good, and I put more in after swapping the thermostat. It all looked pretty good.

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Radiator cap also looked good. I checked that when I added more coolant.

Air pocket was a thought as well. Haven't seen any leaks but I've possibly gotta get it to a shop for a separate, non related issue, so I might see if they'll do a pressure test.

Water pump wasn't even a thought since it's only got 60k miles on it, so it'll probably be the last thing I check.