on my 92 f150 351w i have the factory gauges still so im not sure how accurate they are, but my oil pressure gauge usually sits on the "n" of "normal" but about a week ago the gauge was pointing at the line way past the n. basically saying there was the least amount of oil pressure possible before it would blow up. ive checked the oil level and it is fine. what else do i check or do to fix this if the gauge is right?

 

oil sending unit on the side of the engine. See if it is leaking.

 

how do i find it or what does it look like? which side of the engine?

 

put a after market gauge in, see how that works, is the engine rattling or knocking ?

 

The sender unit is right next to the oil filter. Don't keep driving it until you know for sure what's going on. Best thing to do would be to put a mechanical gauge on there to see exactly how much pressure you have.

 

its not knocking or rattling or anything, it runs as strong as the day i bought it almost 2 years ago. it doesnt help that this is my daily driver and i have no alternate car to drive.

thanks for the help.

 

It's just a Ford thang.

 

Do you use a Fram oil filter? This happened to me, then I put in an FL1A. Back to normal.

 

How many miles are we talking? my 351w (87) has 106, and its just at the "N" but seems to be fine, and sometimes dives when you get off the highway. but thats the least of my issues now, it sits, only being a V-7 bummer. I would try a guage that will give you an actuall reading, and if your miles are up there you may be in need of a new oil pump and some new main bearings.

 

yeah right now i have a fram oil filter on it. sometimes i use the fl1a, i buy either one of those oil filters. i have to change my oil in less than a 1000 miles anyway so ill buy the motorcraft oil filter and see what happens.

i have a 135,000 miles on it. i hope its not the oil pump. i read in my haynes repair manual how to drop the oil pan and it says i have to lift the motor up and take a bunch of things apart, do i really have to do that to take the oil pan out?

if i buy an aftermarket oil pressure gauge how do i hook it up?

 

you can tee off your original sending unit this way both gauges work. kit will come with lines and fittings. you'll prob have to purchase a tee if you want to keep both gauges working. i always do on anything newer than 90, but this is just me. im sure others will have there opions as well. but the gauge is very easy to install. the hardest part is running the line through the firewall

 

Guys... I can't believe no one said this yet.

The factory gauge means NOTHING. It's just an idiot light. As long as there is more than 7psi, it will read somewhere in the normal range. You absolutely can't look at it and say, "My oil pressure reads low!" It just doesn't work that way.

You have to put a mechanical gauge on it to see what your pressure is.

 

I'm curious where you got the 7psi number from....what is that sourced from? I agree the gauge will read that there is normal pressure and that it could infact be low...but I've never seen a reference to exactly how low (you just referenced specifically 7 psi so I'm curious). The stock gauge is not accurate at all and basically shows normal if there is any pressure at all. There is a perfectly good reason for this...but to keep it simple and not get off topic here..its for the people who have no idea what to do if the oil pressure gauge reads low....and for people that don't understand how oil pressure is affected when an engine gets older.

You don't need the stock oil pressure gauge, it has no effect on the truck to disable it. With that being said, just go buy a mechanical oil pressure gauge. It will give you the instructions on how to set it up. Basically you replace the sending unit (unscrew/screw), run a line from that to the dash and mount the gauge itself.

Now once you've got an accurage assessement (from your new gauge) of your oil pressure...you'll be much better able to diagnose a problem (it might even just be the stock sending unit and your engine is ok). However, don't run the engine until you know it has adequate pressures.

Report back your oil pressure findings and then we'll help you figure out what to do. Also, don't use a fram filter...stick wtih the FL-1A's.

 

thanks guys, after i get paid in a couple days ill go pick up a gauge and let you know what i find out. ive been driving my truck since i first posted this and the pressure has been fine, according to my stock gauge anyway. it still worries me sometimes though.

 

I don't have a source for the number, unfortunately. I've seen several different members post the same number in the past, but that's all I'm basing it on. Also, it doesn't take all that much pressure to lubricate the engine with oil. 5-7 lbs is about all you need, but if you fall below that point, you run into problems. So 7 psi jives with what I've seen people post on here.

It does sound awful specific, though.

I'll try and see if I can find something that documents that, as it would be nice to know for sure.