# 98 Jeep Wrangler Antifreeze overflow

**URL:** <https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041>\
**Category:** Maintenance/Repairs\
**Tags:** wrangler, jeep\
**Created:** [November 5, 2009, 12:54am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041 "2009-11-05T00:54:53Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![underpressure](https://avatars.discourse-cdn.com/v4/letter/u/aeb1de/32.png) [@underpressure](https://community.cartalk.com/u/underpressure)\
**Post date:** [November 5, 2009, 12:54am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041/1 "2009-11-05T00:54:53Z")

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I have a 98 Jeep Wrangler v6 that loves to overpressurize the radiator cap during driving and it coats the under side of the hood with antifreeze. I have replace the rad cap with an 18psi cap and replaced the thermostat with a 109 degree thermostat with no result. I have flushed and filled and burped the system with no result. The system does not overheat and temp stay109 degrees. Any further ideas?

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**Author:** ![Xebadaih](https://avatars.discourse-cdn.com/v4/letter/x/d07c76/32.png) [@Xebadaih](https://community.cartalk.com/u/Xebadaih)\
**Post date:** [November 5, 2009, 12:57am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041/2 "2009-11-05T00:57:10Z")

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First off 109 degrees is way to cold. Typo, twice?

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**Author:** ![underpressure](https://avatars.discourse-cdn.com/v4/letter/u/aeb1de/32.png) [@underpressure](https://community.cartalk.com/u/underpressure)\
**Post date:** [November 5, 2009, 1:23am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041/3 "2009-11-05T01:23:24Z")

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That would be correct. 190 instead of the 212 typical of the motor.

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**Author:** ![Xebadaih](https://avatars.discourse-cdn.com/v4/letter/x/d07c76/32.png) [@Xebadaih](https://community.cartalk.com/u/Xebadaih)\
**Post date:** [November 5, 2009, 1:35am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041/4 "2009-11-05T01:35:27Z")

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There is a possibility that you have a blown head gasket and that exhaust gasses are over pressurizing the cooling system. A blown head gasket does not always exhibit obvious symptoms so don’t count it out. The cooling system can easily be checked for the presence of exhaust gases at any shop.

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**Author:** ![underpressure](https://avatars.discourse-cdn.com/v4/letter/u/aeb1de/32.png) [@underpressure](https://community.cartalk.com/u/underpressure)\
**Post date:** [November 5, 2009, 1:38am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041/5 "2009-11-05T01:38:28Z")

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That would make sense of the murky brown film on the rad cap. A blown head gasket would probably also allow slight amounts of oil into the antifreeze or vice versa right?

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**Author:** ![Xebadaih](https://avatars.discourse-cdn.com/v4/letter/x/d07c76/32.png) [@Xebadaih](https://community.cartalk.com/u/Xebadaih)\
**Post date:** [November 5, 2009, 1:42am UTC](https://community.cartalk.com/t/98-jeep-wrangler-antifreeze-overflow/39041/6 "2009-11-05T01:42:08Z")

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Absolutely. Is your oil milky looking? If so, don’t start the engine until the problem is fixed.