Oil gauge not reading right?

[impulse001]

So I just bought a 5.0, and the drive home was about 1 1/2 hours.. Plenty of time to feel out the car for a bit.

When I was crusing around 55-65 MPH the oil gauge would fluctuate between 0 and the first bar. When I was around 85-90 the oil gauge would be around the 2nd to 3rd bar. Why is it reading so low?

 

[LiquidGT]

Replace the sending unit, mine had erratic readings when I first got it.

 

[impulse001]

Replace the sending unit, mine had erratic readings when I first got it.

Well, what is the sending unit and where do I find it? lol

 

[DMAN302]

I would get a good (and had fairly cheap) mechanical gauge on that car if the sender doesn't show anything better on the factory gauge after being replaced. Actually I might be inclined to get my hands on a gauge before replacing the sender (ford dealership will carry..usually 10-20 dollars.) Reason the pressure reads higher at higher speed is because the RPM is higher. Higher RPM means you're turning the pump faster...result is more pressure. Also when the engines cold oil tends to be thicker, combined with a higher cold idle..pressure will be higher than when hot.

First you need to find out IF you have low pressure by checking on a real gauge (stocker is in no way accurate...actually stock ford gauge is not even a decent dummy gauge)

 

[LiquidGT]

Its the thing right next to the oil filter with one wire coming off of it.

 

[impulse001]

Well, i really want to keep the inside of the car as stock as possible, so if I try replacing the sending unit, i take out the cable, and just unscrew the whole thing? Or do i have to unscrew a bolt or something from the bottom with a wrench?

 

[LiquidGT]

Just unplug it and wrench it from the bottom. Didnt take me 5 mins.

 

[NKau]

Well, i really want to keep the inside of the car as stock as possible, so if I try replacing the sending unit, i take out the cable, and just unscrew the whole thing? Or do i have to unscrew a bolt or something from the bottom with a wrench?

Temporarily, unscrew the factory sender, and replace it with a cheap mechanical sender/guage. You don't have to even run it into the car. Just hook it up, leave the cheapo gauge underhood, and see where the oil psi is at a warm idle, and what it does when you rev the motor, then remove, and hook your stock sender back up.

You typically want 10 psi per 1,000 rpm your motor is turning. A fresh/healthy motor should still see 15-25 psi at warm idle though.