Ranger 4x4 with 110k miles on it.

I've been having a weird problem with the oil pressure.  When driving at higher speeds the oil pressure gauge tends to take dives below "L" (low) and shakes and shimmies around there until I reduce speed.  I've added enough oil to make sure it isn't a problem with low oil.

I read somewhere on the internet that Ford had some problems with oil leaks or something in their V6 engines in the early 90s/late 80s.  Could this be my problem?

BTW, fresh oil and filter.

Gauge?
Pump?
Leak?  I haven't noticed a leak anywhere.
'

*sigh*  

Any help would be appreciated.

The shake and shimmy could be caused by an out of balance tire or bent rim.  As for the oil pressure, you might want to replace the oil pressure sending unit.

Sorry, I meant that the needle shakes and shimmies around "L".

About how much will a sending unit cost me?  20-30 bucks?
I'm already up to my ears in bills from my wife's car.

I agree. Check the sending unit first and hope that solves your problem.

check out
[url]www.therangerstation.com[/url]

Goet I'm ashamed that the other previous posts didn't ask you the questions I'm about to ask then give "Prof." advice!
First did this low pressure reading just start or has the oil pressure been low or close to low for sometime and just started getting worse.
If it just started showing low you may have a simple problem which is also a typical one...Bad connection at sending unit. Find sending unit and use some emery cloth to clean the corrosion off the terminal, get some contact cleaner and clean the wire terminal(make sure the cleaner says its plastic safe or it will eat the plastic housing that is typically found around the terminal. Could also be a bad sending unit but they typically show high or low pressure all the time, one or the other not both!! If you have seen a trend in oil pressure being low and just getting lower, find a friend at work, neighborhood, or take it to a garage and have them screw a oil pressure gauge into the oil galley(where the oil sending unit is) and find out what exactly the oil pressure is. If it does indeed get lower as you have higher engine rpm's then you have a bad oil pump or OUCH bad main/rod bearings. If you have any further questions feel free to email me directly anytime. I've been in your boat before...(not alot of money and major problems!)

mjacvn71...Ashamed of what I said?  BFD!  

Just so the whole world knows, I've recentley replaced my the OSU on my truck.  Here is the thread: [url]http://www.ar15.com/forums/topic.html?b=1&f=5&t=139955&w=searchPop[/url]

Oh yeah, I almost forgot.  mjacvn71, KISS MY ASS!

Hey Goet,
I had a similar problem once. Turned out to be the oil pickup screen was partially plugged and there was 100000 little bb balls of cooked oil in the bottom of the oil pan. It would take about 40 miles for the bbs to plug the screen, I would shut engine down, re start, and be on my way. Turns out, draining the oil would not drain the bbs.

Good luck

Several good suggestions here. I'd also like to recommend putting in a can of motor flush a few minutes before your next oil change (read the instructions on the can for details).

Also, if it looks like you're going to have to buy a new oil pressure sending unit, you might instead consider putting in a decent (VDO or Auto Meter) MECHANICAL oil pressure gauge (superior to electrical gauges). It won't cost a heck of a lot more than the replacement sender alone, and will give you much more detailed and accurate oil pressure readings. (Factory gauges are the pits — only a little better than idiot lights!)

Good point skibane...I remember working on a for mustang with a 4cyl. that had low oil pressure reading and it turned out out to be a valid reading. Hence the bad lifters and valvetrain noise! Some idiot had put that black silicone gasket maker on the oil pan and overdid it and the excess crumbled away and plugged the oil pickup screen. Dpeacher show some tact and manners...Geez!

I'll be more then happy to use some tact and manners when you stop the insulting remarks about myself and the others who posted in this thread before you.  

I'll still continue to "insult"   you and the others, review your post you people would see that you gave Goet useless advice! Your link described your problem which was not even remotely similiar to Goet's ranger problem. You had low oil pressure at idle, His oil pressure went low as RPM's went up! DUH! None of you gave him any valuable troubleshooting information. You clowns just said "replace the OPSU". In other words he would most likely be wasting his money on a part that he doesn't need. Yeah there is a chance that it's the OPSU, but find out for sure before wasting the $! I bet the local parts store just loves you replacing parts needlessly!! Don't be a stereotypical jarhead! Use troubleshooting to find out what part or system is bad before you go doing the replace parts, maybe I'll get lucky eventually and end up replacing the bad part....

Ya'all have nice navy day!
VFA-37 Strike Fighter Squadron three seven(Ragin' Bulls)
oct94-oct98 Aviation Electrician's Mate 3rd class USN

Could also be an issue where oil draining from the heads is building up in the lifter galleries - below the intake manifold, I've seen it on V8's.  Could be that something is restricting one of the return holes which allow the oil to drain down into the pan.

That's mighty big talk from a one wire, one enlistment, hide behind the keyboard, dip shit squid.  I would prefer to believe that Goet has enough G-2 to formulate a plan to troubleshoot the gripe after a courteous suggestion.  And that if he had any further questions, he would ask them, or refer to the MIM's.  

Staff Sergeant '84 - '99
F-4 and F/A-18 Aircraft Weapons Systems Specialist / Fire Control Technician  O-level and I-level. (That would be AQ to you there Einstein!)

VMFAT-101 (Sharpshooters)
VMFA-235 (Death Angels)
VMFA-321 (Hell's Angels)
Security Forces Battalion Pacific
MALS-26 (Patriots)
MAG-26
MALS-29 (Wolverines)

Hopefully we will be able to meet someday.  That way I'll be able to show you just how stereotypical this Jarhead can be.

Thanks guys.  I'll print this off and start at the cheap end of suggestions.  Just don't kill each other.  Maybe we should have a mechanics competition instead of shooting meets(?) :D

I really hope it isn't an engine problem.  Just can't deal with that right now.

BTW, it does seem to hold pressure at lower speeds.  I only first noticed this a little while ago when pushing 70mph that it would dip down to Low and then dance around there depending on the RPMs.  Coming back to 30-40 mph brings the needle to a mid-low.

Sounds exactly what my blazer did.....It ended up being a corrosion problem at the terminal of the OPSU and it's wire. I'm not even gonna waste anymore breathe with the knucklehead!

I had the same problem with my oil pressure gauge and water temp gauge on my 89 Ford F-250. It turned out to be a fuse-link that went up to instrument panel. If you still have a problem check that link. Mine was close to battery.
Gavino

A coworker had the same thing happen except to his Bronco. His dad died and he ended up with the Bronco. He changed the oil and went with 5w-30 as Ford recommends, the he put on some off the wall oil filter and the trouble started as you describe. We (the Equipment techs) told him to use the FL1A Motorcraft filter and maybe change back to the 10w-30 his dad had been using. He did and I haven't heard him complain anymore and I see him driving it daily. But, I have seen some oil pickup screens pretty cruddy especially after someone has been into an engine. Plugged with old gasket particles and crap off those 3-M things they use to cut gaskets off with. His oil pressure was fine at idle and went haywire at roadspeeds. IMO, that could be lack of flow caused by a partially plugged oil pickup screen also. Check the sender connections first as the others had mentioned. Good Luck.