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Coolant Gauge Jumping!

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Old May 21, 2008 | 03:03 PM
  #1  
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Default Coolant Gauge Jumping!

I've got a different idle and the coolant range is going up and down 10 degrees every few seconds. I drove about 5 miles from start up and get a check engine flashing light. Pulled over and checked the codes, shows a P300 Current. While stopped the check engine light turns off.
so I turn off the car and restart....check codes again...NO CODES! not even history one for the P300. So I drive and still feel strange idle when stopped at lights. Coolant gauge still fluxuating between 10 degrees. Oil did not climb above 196, since it was a short drive.

Any suggestions on what's the problem?

I think that my themastat is going out or the water pump

I hope it's something more simple. It's been raining pretty good today.

Thanks in advance.
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Old May 21, 2008 | 03:12 PM
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My coolant range is always changing, 196-216 all the time.
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Old May 21, 2008 | 03:15 PM
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Mine stayed at a certain degree, once up to operating tempeture.
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Old May 21, 2008 | 03:50 PM
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Fluctuation in coolant temperatures is sometimes contributed to steam pockets/air voids within the block.
It could also be as simple as road debris blocking the air flow to your bottom breathing radiator. Check the radiator and a/c cores for debris like plastic bags, bugs, leaves, etc.
Maybe it's just the sensor that's bad?
Have you recently changed coolant or drained coolant, then refilled for any reason?
In many cases, simply raising the front of the vehicle may allow the steam pockets/air voids to be released and work their way to the radiator or reservoir.
The REDLINE product called WATER WETTER was designed to help reduce the problem in that it's a water surfactant. It makes the water a bit more slippery and at the same time lubricating the water pump. It can be used with water or coolant. An added bonus is that it may reduce or at least stabilize water temperatures.

Last edited by hotwheels57; May 21, 2008 at 03:54 PM.
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Old May 22, 2008 | 01:30 AM
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Seems the Jet PCM went on the fritz again. I guess it's a inferior product. Once I took it out, the car was back to normal. Seems during the rain storm, the Jet got water logged. Dried it all off and made it home. With the Jet left in, I was getting in the dianostic a no comm message on everything. Seems I am done with the Jet for a few months and maybe forever. Should have got a professional tune.

Thanks for trying to help me guys.

Regards.
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Old May 22, 2008 | 02:20 AM
  #6  
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Originally Posted by Storm Cloud
Seems the Jet PCM went on the fritz again. I guess it's a inferior product. Once I took it out, the car was back to normal. Seems during the rain storm, the Jet got water logged. Dried it all off and made it home. With the Jet left in, I was getting in the dianostic a no comm message on everything. Seems I am done with the Jet for a few months and maybe forever. Should have got a professional tune.

Thanks for trying to help me guys.

Regards.
How exactly does the PCM get water logged?
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