High oil pressure?

ALBERT STEURY

MEMBER
1995 FORD RANGER
3.0L
V6
2WD
MANUAL
220,000 MILES

I began experiencing a slightly higher oil pressure and even though I was not due for an oil change. I went ahead with changing the oil and filter after flushing the engine in hopes that it would resolve the issue. It did not help and within the next few days of driving it short distances it exhibited the following conditions: If I was driving at around 35mph that seemed to give me the lower oil pressure of all the high-pressure readings. If I traveled at 55mph or higher, it would have a higher oil pressure between mid and the highest point on the gauge. The last time I drove it the oil pressure was about 85 % of the way on the gauge to being pegged at high. I have now parked it. I would like to ADD that I have gone to a full synthetic oil using 5w-30 I was wondering if this was a problem. Anything would help. I am on disability with some mental and physical issues, but I am still able to work on my truck. I am self-taught and do have mechanical know how aptitude.

Thursday, September 7th, 2023 AT 2:47 AM

1 Reply

BORIS K

MECHANIC
836 POSTS

Hello,

First, I would suggest checking the engine oil pressure using a mechanical oil pressure gauge. See image 1.

It is best to remove the oil pressure sensor, located on the right rear of the engine.

Removal and Installation:
Disconnect the battery ground cable. Disconnect the engine control sensor wiring from the oil pressure sensor. Image 2
Remove the oil pressure sensor.

Screw in the oil pressure gauge and start engine.
Let it get to operating temperature. The oil pressure will be high with cold engine
Oil pressure at idle
12.5-15 Psi
At 2500 rpm 40-60 Psi

If the readings are correct, then you know that the oil pump is in order, and you might have a possible faulty sender unit or a possible wiring issue between the sender unit and the instrument cluster.

Pin out at sender to cluster, see image 3.
Pin 1, dark green, white wire to cluster pin 5 on connector C214.
Suggest checking this wire pin to pin for a possible resistance issue.
Expect to see less than 2ohm pin to pin.
This can be checked using a voltmeter.

How to use voltmeter:
https://www.2carpros.com/articles/how-to-use-a-voltmeter

How to check wire:
https://www.2carpros.com/articles/how-to-check-wiring

If the readings are high, then you most likely have a sticky oil pressure relieve valve.
This valve is internal in the oil pump.
To access the oil pump, located at the rear of the engine, you will need to remove the oil pan.

Reasons for high oil pressure:
https://www.2carpros.com/articles/high-oil-pressure

A good video for the 3.0L Vulcan V6(this on a Taurus so transverse mount):
https://youtu.be/jk-Fjjv6Ve0?si=Rzar4fEIP-s-fVip

Cheers, Boris

Images (Click to make bigger)