Engine oil change instructions

SAVINIMARK

MEMBER
2001 MERCURY MARQUIS
4.6L
V8
AUTOMATIC
220,000 MILES

When I turn the car on the oil pressure gauge acts normally, but if I have been running it for a while, and I pull up to a stoplight, or have to idle for any period of time while in drive and not neutral, my oil pressure gauge will fluctuate slightly. It does not drop the whole way up and down, it just shimmies and shakes This is new for my car and I am wondering if it is a problem foretelling bad stuff down the road or just an older car with over 200,000 miles on it showing wear and tear? Thanks in advance for letting me know what might be wrong guys.

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,722 POSTS

Hello,

I would start by changing the oil and the oil pressure sensor. Here is a guide to help you with that and I diagram (below) to show you where the sensor is which is down by the oil filter:

https://www.2carpros.com/articles/how-to-change-engine-oil-and-filter

Please let us know what happens.

Cheers, Ken

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Thursday, August 17th, 2017 AT 3:19 PM

SAVINIMARK

MEMBER
2 POSTS

Upon further inspection I believe the problem is electrical in nature, though I am not certain what makes it happen. The problem gets worse if I am using one or more of my electrical devices (ie radio AC defrost).

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Thursday, August 17th, 2017 AT 3:26 PM

KEN L

MASTER CERTIFIED MECHANIC
47,722 POSTS

This can be caused by an alternator that is failing by leaking AC voltage into the system. Here is a guide that will help you confirm the problem.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please let us know what you find.

Cheers, Ken

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Friday, August 18th, 2017 AT 1:10 PM