Question about 1999 Jeep Grand Cherokee

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99 Jeep oil pressure problems

I saw your response regarding an oil pressure problem with a Jeep and I'm having one myself that I hope is also related to the switch. When I start the car first thing in the morning my oil pressure gauge shows around 50. As I pull out of the driveway it begins to fall off. Within two minutes it's down to zero. I usually continue on to work and the pressure bounces around a little but always drops when I idle. If I shut her down and wait 30-40 minutes and then start her up again the gauge reads 40-50 for the rest of the day without much fluctuation. It does not make knocking or rattling sounds so I think it's probably a switch problem but it seems as though you have had a lot of experience so I'd like your opinion.

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  • galoutte Jan 22, 2009

    my gauge goes up and down and it never stop and i have change the sending unit and know i don t know were to go



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Sounds like a bad pressure sending unit, or a partially plugged passage going to it. First though, check that the wire connection is good on the unit. Sometimes just adding a good additive such as marvel oil will free it up sufficiently to restore function. With no noises etc, that's the most likely source of your problem. If not, driving as you have been the engine would be junk by now!!!
Good luck

Posted on Jan 17, 2009


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That is natural. The oil pressure rises in response to engine rpm's.

Idling at a light? Low oil pressure

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Best regards
Mike a6b05ec.gif

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