# 2003 Mercury Grand Marquis - Temp issues

**URL:** <https://community.cartalk.com/t/2003-mercury-grand-marquis-temp-issues/195409>\
**Category:** Maintenance/Repairs\
**Tags:** mercury, radiators\
**Created:** [July 24, 2024, 1:05am UTC](https://community.cartalk.com/t/2003-mercury-grand-marquis-temp-issues/195409 "2024-07-24T01:05:51Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![merv49](https://avatars.discourse-cdn.com/v4/letter/m/9f8e36/32.png) [@merv49](https://community.cartalk.com/u/merv49)\
**Post date:** [July 24, 2024, 1:05am UTC](https://community.cartalk.com/t/2003-mercury-grand-marquis-temp-issues/195409/1 "2024-07-24T01:05:51Z")

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coolant temp rise in slow speeds and hot weather

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**Author:** ![davesmopar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/davesmopar/32/41750_2.png) [@davesmopar](https://community.cartalk.com/u/davesmopar)\
**Post date:** [July 24, 2024, 5:01am UTC](https://community.cartalk.com/t/2003-mercury-grand-marquis-temp-issues/195409/2 "2024-07-24T05:01:29Z")

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> [@merv49](#):
>
> coolant temp rise in slow speeds and hot weather

What about faster speeds, does the temp still rise??

What has been done to find the problem??  
Have you checked the coolant level yet??  
Checked for a coolant leak??  
Is the radiator cooling fan working??  
Is the check engine light on??  
Does the heater still blow very hot air??

If you are seeking help, you will need to answer questions the best you can, or we will only be guessing…

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [July 24, 2024, 11:41pm UTC](https://community.cartalk.com/t/2003-mercury-grand-marquis-temp-issues/195409/3 "2024-07-24T23:41:42Z")

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My first steps with that problem – presuming the coolant level is ok — are to verify the engine compartment fans are spinning like crazy when it starts to overheat, and that the cooling system is holding the correct pressure. If this car still has the original cooling system pressure cap, might be a simple solution to just replace it with a new one. Those caps don’t work correctly forever.

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [July 24, 2024, 11:44pm UTC](https://community.cartalk.com/t/2003-mercury-grand-marquis-temp-issues/195409/4 "2024-07-24T23:44:37Z")

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Does this only happen when the AC is on?

Tester