Overheating Issue, I think?

[matts_6.2]

Hey guys, so I recently replaced the thermostat, coolant temp sensor, and the coolant. Very rarely and at an occurrence of every other week, my car will randomly "overheat" going up to about 260 degrees for coolant temperature cause the AC to shut off and Reduced Power Mode. I don't think the car is actually overheating because when I check under the hood there is no steam and I can touch the hoses for about 2-3 seconds before having to let off. The second reason I think it's an electrical issue is because the temperature would also jump to really hot and then back to normal temps and back and forth. This can occur while driving at highway speeds or sitting idle. I honestly have no clue what could be causing this. Looking forward to and appreciate and help or feedback.

[morepowerjoe]

Maybe one of your fans isn't working. Pop the hood and let the car warm up for about 5 minutes or so unless your in a extremely cold environment then a while longer and then turn on your ac and see if both your fans are on.

[bottletalk]

why did you replace those parts? did u bleed the system after changing the coolant? do u have the right level of coolant in your overflow?
did you check your water pump? with the car off and cold remove ur rad cap. start the car and watch the coolant in the rad, when the engine heats up the thermostat will open and you should see the coolant change/flow at a noticeable speed.
does the pump pulley look good? no slop or play?

[matts_6.2]

Originally Posted by bottletalk

why did you replace those parts? did u bleed the system after changing the coolant? do u have the right level of coolant in your overflow?
did you check your water pump? with the car off and cold remove ur rad cap. start the car and watch the coolant in the rad, when the engine heats up the thermostat will open and you should see the coolant change/flow at a noticeable speed.
does the pump pulley look good? no slop or play?

I replaced those parts because of the current issue. It used to happen more frequently until I replaced them but now it seems that the issue is coming back. I did bleed the system by letting it run with the cap off while keeping it about 2k rpms. In the overflow, when the car is cool the coolant marks halfway on the overflow stick and its nearing the full mark when hot. I have seen the coolant flow when I first changed out the fluid. I will have to check the pulley later today.

[matts_6.2]

Originally Posted by morepowerjoe

Maybe one of your fans isn't working. Pop the hood and let the car warm up for about 5 minutes or so unless your in a extremely cold environment then a while longer and then turn on your ac and see if both your fans are on.

Will do and update you. With the AC on, both fans spin.

[morepowerjoe]

On mine my high speed relay to the fan actually went out and kept my fans from coming on in high speed mode. You might want to check that out too.

[matts_6.2]

Originally Posted by morepowerjoe

On mine my high speed relay to the fan actually went out and kept my fans from coming on in high speed mode. You might want to check that out too.

My fans seem to go into that high speed mode too. Super loud and pushes a lot of air. The only thing I can think of so far is the actual wire from the harness and the water pump. Although I am aware of the radiator, the fans, and the cap.

[gtstorey]

Have you scanned for trouble codes? This could be a wiring issue also. If the ECM looses signal it might go to a max temp.

[matts_6.2]

Originally Posted by gtstorey

Have you scanned for trouble codes? This could be a wiring issue also. If the ECM looses signal it might go to a max temp.

I have scanned for codes, nothing pops up. I'm heavily convinced that it is a wiring issue as well but can't think of anything other than the actual coolant temp connector.

[bottletalk]

Originally Posted by matts_6.2

I have scanned for codes, nothing pops up. I'm heavily convinced that it is a wiring issue as well but can't think of anything other than the actual coolant temp connector.

use a multi meter and verify your wires from the sensor connector to the ECM connector. try running the car with the sensor disconnected, did it trigger a code? check ur temp display while disconnected....I think it fails at min temp on analog but no display on digital.
you still have the original sensor? run the car with ur new sensor connected until it gets to that high temp now turn off the car and quickly disconnect the sensor then take your multimeter set at ohms and measure the resistance in both polarities on the sensor and record ur findings. now duplicate that temp on a stove with a pot of water with the original sensor in it connected to your meter....do you get the same readings? if yes then your car is overheating. if no connect the original sensor electrically only(unless u have a signal generator)to ur car, leave the other in place in the block. try running the car and check if u get temp fluctuations like before(monitor ur rad cuz the fans will not turn on) if yes your analog input on the ecm is shot or u have a wiring issue, if no your car is overheating.

[matts_6.2]

Originally Posted by bottletalk

use a multi meter and verify your wires from the sensor connector to the ECM connector. try running the car with the sensor disconnected, did it trigger a code? check ur temp display while disconnected....I think it fails at min temp on analog but no display on digital.
you still have the original sensor? run the car with ur new sensor connected until it gets to that high temp now turn off the car and quickly disconnect the sensor then take your multimeter set at ohms and measure the resistance in both polarities on the sensor and record ur findings. now duplicate that temp on a stove with a pot of water with the original sensor in it connected to your meter....do you get the same readings? if yes then your car is overheating. if no connect the original sensor electrically only(unless u have a signal generator)to ur car, leave the other in place in the block. try running the car and check if u get temp fluctuations like before(monitor ur rad cuz the fans will not turn on) if yes your analog input on the ecm is shot or u have a wiring issue, if no your car is overheating.

The only problem with this is that I can't just make it fluctuate like that, it seems to be completely random at times. The other week down here it went down to 30 degrees and it did it randomly. I think it may be the ECM signal or wiring somewhere from the ECM to the sensor.

[bottletalk]

I'm guessing you traced the sensor wire back and looked for pinches or breaks. could even be a bad crimp/solder connection in the connector. if u disconnect the sensor and turn the car on does the gauge go high or low?

[Miami_SS]

Originally Posted by matts_6.2

Hey guys, so I recently replaced the thermostat, coolant temp sensor, and the coolant. Very rarely and at an occurrence of every other week, my car will randomly "overheat" going up to about 260 degrees for coolant temperature cause the AC to shut off and Reduced Power Mode. I don't think the car is actually overheating because when I check under the hood there is no steam and I can touch the hoses for about 2-3 seconds before having to let off. The second reason I think it's an electrical issue is because the temperature would also jump to really hot and then back to normal temps and back and forth. This can occur while driving at highway speeds or sitting idle. I honestly have no clue what could be causing this. Looking forward to and appreciate and help or feedback.

I had the same symptoms and it turned out to be a cracked radiator and a blown head gasket which was replaced at the dealer this week ($5k in Miami). See my most recent post. I had the same symptoms and took it to the dealer 2x be4 a competent Tech (at the dealer) diagnosed the issue. I thought it was a thermostat or water pump be4 they did leak down test. The car acts like brand new now but I paid 4 it.