Dholla

Hey Everyone, My oil pressure light keeps coming on and the Gauge drops to low at the same time even though i am full on oil and there is no visible oil leaks.. Everything goes to normal when im driving but sometimes it acts up while driving too...Does anyone know why this could be happening???

akdoggie

Personally, I'd pull the sender first and check the oil pressure with a mechanical gauge. That said, this description is usually an indication of oil pump, or main bearings being worn out. The oil pump isn't bad on these motors to change if necessary. The mains require oil pan removal, and bearings being reinserted, checked, and plastigaged.

This is definitely a bottom end of engine problem. Driving it too much can destroy the crank and or rods. This would require a complete rebuild or another motor. Best to consider your options, before driving this too much. The cost might be too much if you continue to drive it with no or very little oil pressure.

Good old Bill

Good sound advice AKdoggie.

pickupsrule

I had the exact same problem with truck right after I bought it over a year ago. I checked this forum and there were messages about some type of poor connection to the sending unit causing that. I pulled the connection loose, cleaned it, and put it back making sure it was tight and wire was good, and it never did it again. On my truck it is right under the engine near the oil filter and you don't have to jack the truck up to get to it. If that does not fix it then replace the sending unit. In my experience, cars with bad oil pressure usually indicate it at idle all the time or while running all the time. Bad oil pressure usually causes an engine to run hot due to poor lubrication. A good-bad off and on like you describe is usually the sender or electrical connection.
You can also hook a manual oil pressure gauge to the engine and see exactly what it is producing in oil pressure. I think the Ford gauge on the 150 is more like a light and is either on (normal) or off (low). It does not rise and fall with engine RPM on many (or maybe all) 150 engines like a true OP gauge. Kind of like a an "idiot light" in gauge form.
You do need to check it out because low oil pressure can wear out or damage your engine, but I doubt you really have low oil pressure.

akdoggie

I had the same exact thing happen on my 90 with a 5.0 w/gauges. They do tend to loosen and not give a good connection. His 4.6 has a one piece combination switch, with a lock on weatherpac connector, so I doubt that the connection is bad. It probably isn't it in this case.

I still would do the oil pressure check with a mechanical gauge. It takes a 1/4 x 18 thread fitting for the block. Standard Motor Parts number is PS288 in case you need to purchase a new oil pressure sender, if yours turns out bad.

Your description of loosing pressure when it gets hot is a strong indication of worn bearings or a pump though. Let's just hope it's not that deep, and you get out with a switch. Good luck

Dholla

Thanks akdoggie and pickupsrule for the response, I will check all that out tomorrow and I will post what happens when i figure it out... Hopefully its nothing too bad :/ i don't have a lot of money to fix a major problem right now haha