Oil Pressure Gauge Drops To Zero
 

Quick question for you guys. I have an 01 F150 Lariat Supercrew 4x4 with the 5.4 Triton. The truck has 222,000 miles on it. Recently, I have noticed that when I am stopped at a stop light/stop sign while in gear, the oil pressure gauge drops to zero and the light comes on. As soon as I let off the brake and give it gas, it pops back up to normal. While driving, the needle never moves and stays consistent until I stop again, and back down to zero it goes. If I put the truck in Park, the pressure goes back to normal. Same with neutral. It seems it is hit or miss and does not do this all the time, but I just wanted to see what your thoughts are. After doing some research I am leaning towards an oil pressure sensor/sending unit, but before I put money towards something I was looking for opinions from all of you. The truck runs perfectly fine, I just want to make sure it is not something more serious. Thanks! :-X22

Well, you could either replace the sending unit first or you can connect an oil pressure gauge to see what's actually happening. Either way, you'll have to get out there and do something.

"Getting out there and doing something" is no issue for me. But, currently I am sitting in my office at work and cannot do so until I get home. I was looking for a little heads up, or someone to come in and say "Hey, had the same thing happen to me, I did (insert procedure here)." Thanks.

Well, my 97 5.4 did it when it's up to temp from a dead stop, but it "blinks" the light on, and the needle drops quickly, and almost bounces back up. If I take off easy, it doesn't do it.

The needles in these (from what i've read elsewhere in here) are electronic, and are "on/off" and not worth much more than letting you know you're low on oil and need to get some in it ASAP. They're not really useful for watching actual oil pressure is what I'm saying..

I read about using 5/20w oil, for fuel mileage, being okay to use in these, and granted it was a dumb idea at 195K miles, but I did, and that's when I started noticing it. But in the cold, I've never seen it do it again. Mine is burning almost a quart per 1000 miles, so I've been watching that, and I'm sure if I let it be a quart low it would come back on.
I think it's a combo of old engine and oil that is too thin to be in the engine, but It's 30 degrees all winter lol I can't test anything else til summer

It's currently 30 degree's here, but in the past 5 days we have received 20" of snow. It started around then. I had just changed my oil about 2 weeks ago. The truck doesn't use any oil, and when I checked it last night, the oil was still at the same/correct level. The only oil I use, and have been using for the past 3 years, is the Penzoil High Mileage oil.

While doing my research I had also read about the oil pressure gauge on these being "inaccurate" to a certain degree. I also read there was a "bypass" of sorts to help make the oil pressure gauge a little more accurate, although not 100%. Thanks for the info! :-X22

Before dumping a oil sending unit on it, which lets face it, probably needs changed with a quarter of a million miles on it, could try the seafoam treatment, you'd have to change your oil again tho... just another trial type thing ya could do.

As mentioned above,put a mechanical gauge on it and see what
the pressure is at a hot/warm idle.

As mentioned above,put a mechanical gauge on it and see what
the pressure is at a hot/warm idle.

sending unit
 

i can almost tell u for certain its the sending unit. easy fix, just unscrew the old one screw in the new one, it's that simple. u might want to screw in a oil pressure tester just to see where u are at pressure wise with that many miles on the truck because the gauge is more of a switch than a gauge.

The gauges on Ford basically work like an idiot light. Low or no pressure indicates below 5 lbs or so, anything within any kind of normal range puts the needle at about 55-60% where it stays. Ford uses a fixed resistor--the reason is that owners would freak out when the pressure got semi-low at a hot idle.

You either have a serious low pressure problem or a bad sending unit. Either change out the sending unit or put a real gauge on it. I'll bet it's a bad sending unit.

Good luck,
George

For my 3 and a half cent worth, the oil sender is just a switch.
There is no accuracy to it. It either closes a ground to the dash or it dosen't.
It normally closes on 5 to 7 psi.
For oil pressure as an example, I have 186,000 on my motor.
With an electric oil pressure gage and sender on for the last 100,000 plus miles, the hot idle pressure is 25 psi, the running pressure is 70 psi+/-.
You need to test it to tell what condition the pump and bearings are in for full knowledge or replace the sender switch and accept if the gage come up to normal position just telling you the switch is closed.
Good luck.

Couldn't read all the post . Just put a new sending unit in , ford did mine for $75 i believe fixed problem or if u want to get in there yourself. Seafoams never worked for anything iv used it for

The absolute best thing I've ever seen it do was fixed a non-functional fuel gauge lol It really seemed to help my ANCIENT 4.3 in it. But I realize there's a lot of opinion on that.



Anyways OP what's the bottom line? You changing the switch or did ya get a gauge?

Changing cooling lines on my 97 4.6L and getting that bugger out is virtually impossible. Does the sending unit unscrew at both ends (that is in the line connection as well as the wire harness end?

Doesn't look to be a standard detachable connector setup.

The connector has a snap lock on it so it stays on.
There different but the coils and injectors all have locks on them.
Better to remove the oil filter to get at it better.
Good luck.