Coolant Temp 299!?
Thread Starter
Racer
Joined: Sep 2022
Posts: 338
Likes: 67
From: Escondido, CA
Coolant Temp 299!?
My Coolant Temp guage climbs steadily to 299 and stays. I just replaced the Thermostat. Also, the Low Coolant warning stays on, even though I just had the coolant flushed at Jiffy Line. The Oil Temp gauge says “Lo” (oil pressure is 53 at idle). The aux fan goes on when the coolant temp shows 285.
I’ve just now been running it at idle with the hood up, in the garage (it’s about 85F outside) and after about 15 minutes the main fan started and oil temp is 165. It’s been about 25 minutes and the oil is at 230. Oh, and the low coolant warning light is off.
Those aware of my recent posts know that I made a mistake and got oil in my radiator; I’ve flushed that.
Any suggestions on how to troubleshoot?
I’ve just now been running it at idle with the hood up, in the garage (it’s about 85F outside) and after about 15 minutes the main fan started and oil temp is 165. It’s been about 25 minutes and the oil is at 230. Oh, and the low coolant warning light is off.
Those aware of my recent posts know that I made a mistake and got oil in my radiator; I’ve flushed that.
Any suggestions on how to troubleshoot?
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
I'd suggest starting with an IR temp "gun" to see if the measurements at the thermostat housing / radiator inlet are in rough agreement with what the temp gauge says.
And is this temp measurement based on the "analog" gauge, or is this based on the coolant temp show in the DIC (LT1 cars).
And is this temp measurement based on the "analog" gauge, or is this based on the coolant temp show in the DIC (LT1 cars).
Melting Slicks
Joined: Feb 2003
Posts: 2,668
Likes: 809
From: Saskatoon Sask.
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
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Thread Starter
Racer
Joined: Sep 2022
Posts: 338
Likes: 67
From: Escondido, CA
OK, update.
Did some more research here and found a few mistakes I made; the main being that when I filled the coolant I only did it at the radiator, when I should have also filled the engine at the thermostat.
Then I read some articles that got me a bit concerned that perhaps I may have blown a gasket.
So I filled the engine and then got a combustion leak tester. Good news is that the fluid stayed blue. Also the oil is still clean.
BTW, on the subject of the leak tester; no one, in what I read here or on the tester instructions, warned me to replace the radiator cap when I’m done with the test. By that time, the thermostat is open and the fluid is circulating. I turned off the engine and hot radiator fluid spewed!
So, cleaned that up and now waiting for the engine to cool down, then will top off at the thermostat again and at the radiator. Then I’ll test again.
Did some more research here and found a few mistakes I made; the main being that when I filled the coolant I only did it at the radiator, when I should have also filled the engine at the thermostat.
Then I read some articles that got me a bit concerned that perhaps I may have blown a gasket.
So I filled the engine and then got a combustion leak tester. Good news is that the fluid stayed blue. Also the oil is still clean.
BTW, on the subject of the leak tester; no one, in what I read here or on the tester instructions, warned me to replace the radiator cap when I’m done with the test. By that time, the thermostat is open and the fluid is circulating. I turned off the engine and hot radiator fluid spewed!
So, cleaned that up and now waiting for the engine to cool down, then will top off at the thermostat again and at the radiator. Then I’ll test again.
Thread Starter
Racer
Joined: Sep 2022
Posts: 338
Likes: 67
From: Escondido, CA
OK, update.
Did some more research here and found a few mistakes I made; the main being that when I filled the coolant I only did it at the radiator, when I should have also filled the engine at the thermostat.
Then I read some articles that got me a bit concerned that perhaps I may have blown a gasket.
So I filled the engine and then got a combustion leak tester. Good news is that the fluid stayed blue. Also the oil is still clean.
BTW, on the subject of the leak tester; no one, in what I read here or on the tester instructions, warned me to replace the radiator cap when I’m done with the test. By that time, the thermostat is open and the fluid is circulating. I turned off the engine and hot radiator fluid spewed!
So, cleaned that up and now waiting for the engine to cool down, then will top off at the thermostat again and at the radiator. Then I’ll test again.
Did some more research here and found a few mistakes I made; the main being that when I filled the coolant I only did it at the radiator, when I should have also filled the engine at the thermostat.
Then I read some articles that got me a bit concerned that perhaps I may have blown a gasket.
So I filled the engine and then got a combustion leak tester. Good news is that the fluid stayed blue. Also the oil is still clean.
BTW, on the subject of the leak tester; no one, in what I read here or on the tester instructions, warned me to replace the radiator cap when I’m done with the test. By that time, the thermostat is open and the fluid is circulating. I turned off the engine and hot radiator fluid spewed!
So, cleaned that up and now waiting for the engine to cool down, then will top off at the thermostat again and at the radiator. Then I’ll test again.
Thread Starter
Racer
Joined: Sep 2022
Posts: 338
Likes: 67
From: Escondido, CA
I ensured that it was really topped off… and everything works. It’s 100F today and I drive it to get tires then smogged (it passed!) and the temp stayed below 230. Drive away from the light, get up to speed, and goes down to 212ish.
So then here’s my theory, somebody correct me if I’m wrong.
I think that, because it was truly low, the fluid was not contacting the temperature sensor so the sensor was really getting that high but the rest of the engine was not. I’m just guessing, really don’t know why it would get that high but not do damage. But like I said, passed smog, oil’s clean, no funny smells, idle and runs solid.
So then here’s my theory, somebody correct me if I’m wrong.
I think that, because it was truly low, the fluid was not contacting the temperature sensor so the sensor was really getting that high but the rest of the engine was not. I’m just guessing, really don’t know why it would get that high but not do damage. But like I said, passed smog, oil’s clean, no funny smells, idle and runs solid.
