Low oil pressure light

Tiny
TARA B
  • MEMBER
  • 2002 MERCURY MOUNTAINEER
  • 4.0L
  • V6
  • 2WD
  • AUTOMATIC
  • 115,000 MILES
I was driving my SUV and went to slow down at a red light and my low oil pressure light came on and my SUV shut off. I went to start it and it would turn over all the way. I had it towed home. I checked my oil level and it was fine. I did some research and thought it was the oil pressure sensor so I replaced that. My SUV still didn't start fully but this time sounded more like a dead battery. Not wanting to take any chances I took the alternator and the battery off and took them to be tested. The alternator was fine but the battery was not. I bought a new battery. I took them home placed the alternator and new battery. The vehicle started just fine. I drive around the block and allowed it to just idle for a bit and all was well. I went to drive it today and got about four blocks from home and the low oil pressure light came back on. I just don't know what else to do. Maybe the oil pump? Please help. Thank you in advance for your time and consideration.
Monday, March 18th, 2019 AT 2:24 PM

3 Replies

Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello,

This could be a problem with the wire coming from the oil sending unit. The threaded stud on the bottom needs to be clean and oil/dirt free. If the connector on the wire is stretched out, you can take a pair of pliers and crimp it back down, so it makes a nice solid connection.
I have included in the diagrams down below, the factory troubleshooting diagnostic flowchart for your cars Oil Pressure System. It will require you to install a Oil Pressure Test Gauge, but you should be able to rent this for free at your local auto parts store. Get back to us with what you find out.

Thanks,
Alex
2CarPros
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Monday, March 18th, 2019 AT 4:26 PM
Tiny
TARA B
  • MEMBER
  • 2 POSTS
Ugh! So I thought let me go ahead and do a oil change and filter replace and found metal shavings in the oil. So I'm sure I'm now looking at a bigger bearing issue if not rebuild.
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Monday, March 18th, 2019 AT 5:04 PM
Tiny
SCGRANTURISMO
  • MECHANIC
  • 4,897 POSTS
Hello again,

Yes, unfortunately, metal shaving in your oil is usually a sign that your bearing have not been getting properly lubricated and have gone metal to metal and shaving themselves down. If there is a lubrication failure it is usually the top end of the engine to go first, since it is the farthest away from the oil pan and the oil has to travel the farthest to get up there. That means the camshaft bearings, although, it still might possibly be the main bearings or connecting rod bearings. You can tell pretty quickly if your engine is an overhead valve design, by simply taking off the valve covers and your camshaft(s) should be right there.
Anyways, sorry to hear that and let us know what you find out.

Thanks,
Alex
2CarPros
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Tuesday, March 19th, 2019 AT 4:31 AM

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