# Oil pressure guage not working until warm, 99 Mountaineer V8 AWD

**URL:** <https://community.cartalk.com/t/oil-pressure-guage-not-working-until-warm-99-mountaineer-v8-awd/7874>\
**Category:** Maintenance/Repairs\
**Created:** [December 1, 2007, 2:16pm UTC](https://community.cartalk.com/t/oil-pressure-guage-not-working-until-warm-99-mountaineer-v8-awd/7874 "2007-12-01T14:16:23Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jonnruth123](https://avatars.discourse-cdn.com/v4/letter/j/ee59a6/32.png) [@Jonnruth123](https://community.cartalk.com/u/Jonnruth123)\
**Post date:** [December 1, 2007, 2:16pm UTC](https://community.cartalk.com/t/oil-pressure-guage-not-working-until-warm-99-mountaineer-v8-awd/7874/1 "2007-12-01T14:16:23Z")

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Here’s another one for the experts. My oil pressure guage stays flatlined until about 5 miles down the road, and the colder it is, the longer it takes to function. The check gage light also stays on until the gauge functions. A mechanic at Valvoline thought it was a oil pressure sending unit. Any ideas!  
  
  
  
 BTW, this site is great, I was able to fix my heater(faulty t-stat), thanks to this site.

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**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\
**Post date:** [December 1, 2007, 8:23pm UTC](https://community.cartalk.com/t/oil-pressure-guage-not-working-until-warm-99-mountaineer-v8-awd/7874/2 "2007-12-01T20:23:44Z")

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I would have a MECHANIC, not an oil changer, check the actual oil pressure with a calibrated gauge (not the one on the dashboard). If the pressure is OK, it’s probably a bad pressure sender.

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**Author:** ![Johnm6211](https://avatars.discourse-cdn.com/v4/letter/j/e99b99/32.png) [@Johnm6211](https://community.cartalk.com/u/Johnm6211)\
**Post date:** [December 4, 2007, 1:25am UTC](https://community.cartalk.com/t/oil-pressure-guage-not-working-until-warm-99-mountaineer-v8-awd/7874/3 "2007-12-04T01:25:56Z")

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This is usually caused by the “Oil Pressure Sending Unit” failing. This hardley ever has anything to do with the engines actual oil pressure, the oil pressure does exist it is just that the gauge does not read ir for a short time after cold start up.

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**Author:** ![Jonnruth123](https://avatars.discourse-cdn.com/v4/letter/j/ee59a6/32.png) [@Jonnruth123](https://community.cartalk.com/u/Jonnruth123)\
**Post date:** [December 4, 2007, 4:53am UTC](https://community.cartalk.com/t/oil-pressure-guage-not-working-until-warm-99-mountaineer-v8-awd/7874/4 "2007-12-04T04:53:43Z")

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Look closely MORON, I said MECHANIC! He owns the franchise.

Thanks Johnm6211, advice I could actually use!