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Oil pressure low

Tiny
BRYANFORSTE
  • MEMBER
  • 2005 BUICK LESABRE
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 267,000 MILES
Noticed my oil light flicker on off a couple times. Switched my digital to oil pressure the next drive and it's normal is 130psi. Car didn't fluctuate at cold idle and oil level was good. After driving a few miles it would drop to the 80's and quickly bounce back to 130. After about 30 miles it started to drop further and then bounce right back. Seemed to be less frequent after turning ac and vents off, but still occurring. Worse on acceleration and better at steady speed. Any suggestions? I have a few thoughts but don't want to influence advice. Thanks in advance.
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Saturday, July 20th, 2019 AT 12:28 PM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Welcome to 2CarPros.

Is the oil level full and clean? Also, have you checked the oil pressure switch to make sure the wiring and connector is in good condition? Also, check to see if there is any oil leaking from the sensor.

Here are the directions for replacing the pressure sensor. I'm adding them so you for location and if you find it is leaking, it will need replaced.

_____________________________________

ENGINE OIL PRESSURE SENSOR/SWITCH
Engine Oil Pressure Sensor and/or Switch Replacement

Tools Required
- J 41712 Oil Pressure Switch Socket

Removal Procedure
1. Raise and support the vehicle. Refer to Vehicle Lifting.

Pic 1

2. Disconnect the electrical connector from the engine oil pressure switch (1).
3. Remove the engine oil pressure switch (1) from the oil filter adapter using the J 41712.

Installation Procedure

pic 2

Notice: Refer to Component Fastener Tightening Notice in Service Precautions.

1. Install the engine oil pressure switch (1) to the oil filter adapter using the J 41712.
Tighten the engine oil pressure switch to 16 Nm (12 ft. Lbs.).
2. Connect the electrical connector to the engine oil pressure switch (1).
3. Lower the vehicle.
4. Inspect for oil leaks after engine start up.
5. Adjust the engine oil level to the full mark.

________________________________________

Let me know if this helps and what you find.

Take care,
Joe
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Saturday, July 20th, 2019 AT 10:33 PM
Tiny
BRYANFORSTE
  • MEMBER
  • 6 POSTS
Thank you so much jacobandnickolas for your thorough response with replacement instructions, did not know a special socket was going to be required but glad I didn't have to make another trip to get it. 130psi was almost double what it is now, after a new sensor/switch (same thing popped up after searching both ways.) Now I average 65psi instead of 130psi. Higher when cold or accelerating and lower when warm or decelerating. Fluctuates only with rpms and not speratic anymore. Thanks guys you nailed it!
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Sunday, July 21st, 2019 AT 11:22 AM
Tiny
BRYANFORSTE
  • MEMBER
  • 6 POSTS
Also, my sensor was not leaking, wires looked fine, but with high mileage (267000mi) looked a little gummed up in the hole.
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Sunday, July 21st, 2019 AT 11:24 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Okay what is probably happening is the engine oil pick up is getting clogged causing the low oil pressure issue can you confirm regular oil changes? If not here are diagrams and instructions to remove the oil pan so you can clean it. Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.
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Tuesday, July 23rd, 2019 AT 2:49 PM
Tiny
BRYANFORSTE
  • MEMBER
  • 6 POSTS
It ended up being the oil switch/sensor.
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Tuesday, July 23rd, 2019 AT 3:45 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Welcome back:

Great! At least that was an easy fix. As Ken mentioned, I was starting to question if it was something more difficult to fix.

Regardless, I'm glad you got it taken care of. Let us know if you have questions in the future.

Take care,
Joe
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Tuesday, July 23rd, 2019 AT 7:41 PM
Tiny
ZEAK
  • MEMBER
  • 1 POST
  • 1997 BUICK LESABRE
  • 3.8L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 19,000 MILES
I hear qweaking sound every so often. Is mean I need a new oil pump or a new oil pressure switch?
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Wednesday, July 24th, 2019 AT 6:42 PM (Merged)
Tiny
FREEMBA
  • MECHANIC
  • 1,152 POSTS
Low oil pressure usually causes a tapping or knocking sound.
To be safe have your oil pressure checked at a good shop, using
a different oil pressure gauge (not the one on the dash of the car).
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Wednesday, July 24th, 2019 AT 6:42 PM (Merged)
Tiny
TCCC143
  • MEMBER
  • 21 POSTS
  • 1994 BUICK LESABRE
1994 Buick LeSabre low oil pressure. I have replaced the oil pump gears but my oil pressure is still at less than 10psi. When I first start it in the morning it is at 45 and drops as the engine heats up. What can I do?
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Wednesday, July 24th, 2019 AT 6:42 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Hi there,

You may have a faulty pressure regulator valve, but if your car has a lot of miles on the speedo you may be looking at worn crankshaft bearings, if the oil clearance there is more than specified low oil pressure will be the result, an engine re build is the only recommended fix.

Mark (mhpautos)
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Wednesday, July 24th, 2019 AT 6:42 PM (Merged)

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