# Coolant level mystery

**URL:** <https://community.cartalk.com/t/coolant-level-mystery/58641>\
**Category:** Maintenance/Repairs\
**Tags:** pontiac, coolant\
**Created:** [December 13, 2010, 3:07pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641 "2010-12-13T15:07:24Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Steve\_H1](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@Steve\_H1](https://community.cartalk.com/u/Steve_H1)\
**Post date:** [December 13, 2010, 3:07pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641/1 "2010-12-13T15:07:24Z")

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My "95 Pontiac Grand Prix has had the coolant level sensor, located on the side of the radiator, replaced twice now by my mechanic. The “LOW COOLANT” light still comes on, sometimes dimly or flickering, frequently. The radiator is always full and the coolant recovery bottle is at the proper level. The engine temperature stays in the normal range once it warms up. What else could it be??

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**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [December 13, 2010, 3:09pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641/2 "2010-12-13T15:09:43Z")

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The only thing left is the wiring for the sensor. Loose connection, chafed insulation, etc.

Although, when you say the sensor was replaced twice - in how much time?

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**Author:** ![jesmed1](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/jesmed1/32/2097_2.png) [@jesmed1](https://community.cartalk.com/u/jesmed1)\
**Post date:** [December 13, 2010, 3:12pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641/3 "2010-12-13T15:12:54Z")

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See post #19 at the bottom of this link:

> **[Pontiac Grand Prix Flashing low coolant light](https://forums.edmunds.com/discussion/7967/pontiac/grand-prix/pontiac-grand-prix-flashing-low-coolant-light)**
>
> I have 1997 grand prix, with 3800 series II engine. This has start about 3 days ago. I have checked the coolant level, which is at the proper level.

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**Author:** ![Steve\_H1](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@Steve\_H1](https://community.cartalk.com/u/Steve_H1)\
**Post date:** [December 13, 2010, 3:40pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641/4 "2010-12-13T15:40:09Z")

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The problem showed up again within a week (wife’s car, doesn’t drive much). I had it replaced again within 30 days.  
Steve\_H.

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**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\
**Post date:** [December 13, 2010, 5:22pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641/5 "2010-12-13T17:22:27Z")

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You probably need a coolant flush. These low coolant sensors that are mounted in the rad get contaminated pretty easily.

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**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [December 13, 2010, 5:34pm UTC](https://community.cartalk.com/t/coolant-level-mystery/58641/6 "2010-12-13T17:34:28Z")

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See pete p’s comment below which is what I was thinking. I don’t know this sensor’s design but they are often just electrodes where the coolant completes contact. The electrodes can easily pick up certain kinds of contaminants out of the coolant. Then they can’t pass the signal.