EOT and ECT fluctuation - intermittent heat

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Dec 16, 2018 | 04:02 PM

Gunt

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EOT and ECT fluctuation - intermittent heat

Recently I have noticed a constant fluctuation in my eot and ect temps. I installed a mishimoto thermostat a few months back and my temps were perfect 198-202 coolant and oil was never more than 10 degrees warmer no matter how I drove. Now I’m noticing a difference in coolant temps that moves from 180s to low 200s and my oil temps will sometimes drop drastic, like from 205 down to 170 in just seconds and come right back to 205 or even hover in the 180s. It’s really all over the place. I’ve lost heat until I drive for almost 45 minutes as well. After a cold soak the temps are within a few degrees of eachother. I have some coolant I have noticed dripping off bottom of my radiator but it’s not a lot and coolant level holds steady. Any ideas? Today I topped my coolant off to the minimum line and ran the truck with the degas cap off. I gained enough coolant for the level to reach the max line on degas bottle. I’m stumped.

Dec 16, 2018 | 06:30 PM

xcrsp440

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I had a bad head gasket in a car and it exhibited the same symptoms. As the air got trapped in the system and went past the sensors there is nothing for them to read and temp drops, then as coolant flows thru again, there is something again to read and temp shoots back up. Same thing with the heater, air gets in core and no heat is produced. Have you had the coolant system apart recently, maybe got an air bubble in it?

Dec 16, 2018 | 06:41 PM

Nummy76

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The first things to pop in my head were air in the cooling system and/or temp sensors, possible corrosion or loose wire grounding problem

Dec 16, 2018 | 07:03 PM

Gunt

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I have had it open but that was about 2 months ago. I am wondering if I have a radiator leak that is sucking air. Anyone have experience with that?

Aug 10, 2021 | 12:31 PM

JohnCash

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Gunt are you still around? This is happening to my truck, did you figure it out?

Aug 10, 2021 | 01:09 PM

Gunt

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Quote:

Originally Posted by JohnCash

Gunt are you still around? This is happening to my truck, did you figure it out?

I wish I could help more. I traded this truck in and it was exhibiting the problems until the day I did. After a few months and having to replace coolant monthly I assumed a failing head gasket or another failed oil cooler and chalked up my loss and bought a Tacoma. I hope you get it figured out…I don’t miss my headache of being a 6.0 owner!

Aug 10, 2021 | 01:18 PM

JohnCash

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That's funny, I sold my Tacoma for the Excursion 6.0. Needed more seats! In a week I'm replacing the oil cooler and EGR cooler with BPD parts so I might just let it sit until then and avoid any issues. Thanks for the reply, enjoy the taco!