Zero oil pressure 80 MPH ?

[RickMar]

Hi, Thank you for taking the time to read this thread.

Many of us know of the infamous oil pressure sending units that have spooked many Explore and Mountaineer owners for years when the gauge indicated "Zero" or did other strange things.
Well as usual the leaves "Fall" and the Explorers and Mountaineers start to "Fall" apart. Making us all smiling happy people as we brace the wind, stand in the rain, shiver until our teeth almost fall out while completing our auto repairs makes everything just delightful huh?
Here it is for me. I am traveling down the highway at 75 - 80 MPH for 4+ years I have seen my oil pressure gauge read zero and I could just about put a mark in the road when it will return to normal. This day was different from all those years. At 80 MPH I see "Check Gauge" I look around thinking loe fuel, then I see Zero on my oil pressure gauge, I have seen this many times in the past and know it is the faulty sending unit I never replaced, This time I was WRONG , IT WAS INDICATING THE TRUTH !!
I drove along about 5 miles to my exit and stopped at a light, YEP sounded like the engine was toasted. Parked the vehicle and expected to not hear it run again after it cooled down. To my surprise it started... plenty of oil pressure and the clattering noises stopped completely.
Could anyone explain why my oil pressure would drop and then return to normal? Any information will be appreciated,
Thank you ,
Rick

 

[1998Explodasport]

Is there enough oil in it?

 

[SoNic67]

My guess:
You might have clogged return passages and the oil cannot return in the oil pan fast enough. At high RPM, the pump pushes all the oil "up" from the oil pan and eventually has no more oil to "suck", therefore low oil pressure.
After you stop, the oil will seep back in the pan and you have again oil pressure.

 

[Mbrooks420]

This is the perfect reason to actually replace a faulty sender, or better yet,install a real gauge. If the above is true about the clogged oil passages, might be time for some atf in the oil, and then a change. Is the oil level all the way full?

 

[RickMar]

Thank you all the the replies, I appreciate it very much.
Yes ...the oil is filled to capacity.. actually a bit over.
I have 220,00+ miles on the clock so I am leaning toward the advise of SoNic67. It makes perfect sense, the passages have seen a lot of oil over the past 11 years.

Mbrooks420 - How much ATF and how long of a cycle would you suggest?

I will be installing a gauge after this scare... I thought I toasted the engine without a doubt...I was very surprised and did not expect it to start
Thanks again.
Rick

 

[Mbrooks420]

I have never actually done this. I have heard about from several "old timers". Usually a quart of atf, and change it in short order. Maybe a few hundred miles. The detergents in the ATF should work fairly fast. A more modern approach might be Seafoam, and run it for longer.

 

[SoNic67]

I am in the same "boat" with my oil pressure. Actually I might be even worse since my wife heard a loud noise in the engine while driving it and the CEL came on - I will find out more this weekend...

I am VERY pissed that Ford put a fake gauge for oil "pressure" and not a real one. Now I have a T in the pressure port with a mechanical tube going to a mechanical pressure gauge sitting on the top on my dash.

 

[Mbrooks420]

http://www.explorerforum.com/forums/showthread.php?s=&threadid=14894

Shows how to convert the "oil pressure gauge" into an oil pressure gauge.

 

[RickMar]

Thanks again ...
The old timers do know a lot of tricks that work great but I think I'll go with the SeaFoam. I appreciate the info.

SoNic67... good luck with the CEL I hope it is not a major problem.
Thanks again for the info, I appreciate it.

Rick

 

[kevinsranger]

when my vacuum modulator diaphram went bad on my a4ld on my 94 ranger, it was sucking all the trans fluid out and into the intake of my truck, and somehow getting into the oil, well needless to say now that i fixed the modulator, i have the cleanest oil when i check it and the engine has 300,000 miles on it and running perfect

 

[Rudy602]

I'm not sure how you would get much ATF in your oil by having it sucked into the intake and combustion chambers. Usually a lot of white smoke.

 

[2000StreetRod]

using existing indicator

http://www.explorerforum.com/forums/showthread.php?s=&threadid=14894

Shows how to convert the "oil pressure gauge" into an oil pressure gauge.

I believe driving the existing indicator with an oil pressure sending unit instead of the stock oil pressure switch only works on some specific years of 1st generation Explorers. The indicator was modified in later years so it can't function as a gauge. That's why I added a pillar pod gauge driven by a sending unit: Oil pressure gauge

 

[kevinsranger]

I'm not sure how you would get much ATF in your oil by having it sucked into the intake and combustion chambers. Usually a lot of white smoke.

quite a bit for some reason, i kept watch on it on the engine oil dipstick and kept draining it before i figured it out lol

 

[Rudy602]

strange....any smoke show?

 

[kevinsranger]

strange....any smoke show?

not at all, that i noticed anyway. i only imagine it went thru the intake because it was getting sucked thru the vacuum line, but the crankcase was the part getting filled

 

[Hitchhikingmike]

Rickmar, what engine do you have SOHC V6, OHV V6 or V8?

 

[Rudy602]

Yeah, I don't know where it taps that motor for vac. but the intake was a likely spot in the days of vac. modulators and the white smoke show was impressive -- you had to smile at the sight.

 

[RickMar]

Hi - Hitchhikingmike

I have a V8 5.0L (302 cu. in.)

Rick

 

[Mbrooks420]

I believe driving the existing indicator with an oil pressure sending unit instead of the stock oil pressure switch only works on some specific years of 1st generation Explorers. The indicator was modified in later years so it can't function as a gauge. That's why I added a pillar pod gauge driven by a sending unit: Oil pressure gauge

Ahh. That's unfortunate. A real separate gauge is probably the best thing anyways.