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95 XLT 5.8L
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Discussion Starter · #1 ·
This is about where it seems to be at most of the time, but it seems to fluctuate a little. every once in a while when I check it on the highway or whatever it’s more like a third “full”, or maybe a quarter, somewhere around there. But it tends to hang right around here for the most part. And yes I’ve checked the oil level and it’s fine, and at one point, before my last oil change, it was a bit high, according to the dipstick, even tho I put in the exact recommended oil quantity I got from a post on here and corroborated with Oil and Fluid Capacities | The best source of automotive and light truck oil and fluid capacities. and several other sources, and I had still been getting the same pressure reading
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1986 Bronco Eddie Bauer 5.0 mostly stock
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Have you checked the connection on your sending unit? Not sure where it is on a 95 but on my 86 its right there kind of behind the PS pump, take that wire off and put it back on make sure its good and snug.

How many miles you got, what kind of oil you running? It may be time to go a shade thicker if it's got a billion miles on it and you're still running 10w30. Then again, some pressure is better than no pressure and i know when it came to old SBC engines...if it had like 7lb of pressure...it was good...run it.
 

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The Tennessee Warden
96 XL, built 357W, E4OD, BW1356, 4.56 gears
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You’re oil pressure is most likely fine, but your oil pressure switch could be faulty. Or, the wire connection on the switch could be dirty. You can test the switch by grounding the stud on top of it. I believe @miesk5 has a good procedure for testing it, as well as the gauge itself. The switch is a cheap part and pretty easy to replace. It’s located on the engine block, just above the oil filter and toward the front a bit. You should use an oil pressure switch socket to remove it to prevent breaking it.
 

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95 XLT 5.8L
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Discussion Starter · #4 ·
Have you checked the connection on your sending unit? Not sure where it is on a 95 but on my 86 its right there kind of behind the PS pump, take that wire off and put it back on make sure its good and snug.

How many miles you got, what kind of oil you running? It may be time to go a shade thicker if it's got a billion miles on it and you're still running 10w30. Then again, some pressure is better than no pressure and i know when it came to old SBC engines...if it had like 7lb of pressure...it was good...run it.
It’s got about 175k miles on the odometer, and I run 5w30. I did think about going to thicker oil but I was wary of going against Ford’s recommendation in the owner’s manual
 

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1986 Bronco Eddie Bauer 5.0 mostly stock
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It’s got about 175k miles on the odometer, and I run 5w30. I did think about going to thicker oil but I was wary of going against Ford’s recommendation in the owner’s manual
First off, as mentioned, check your oil pressure switch wiring. Provided all that is good, as long as the pressure is "steady" and settles out once it gets to operating temp (aside from the typical rise and fall with RPM) then you can probably still keep running the same oil.

However, I'm going to say that at 175,000 i think you'd be more than safe to run a 10w30 oil...i think those new tolerances have loosened up a bit. Do some studying into it though beyond my pea-brained analysis. I do know its a shade thicker and should make the pressure a bit higher if the low pressure bothers you that much.

Please for the love of God don't put "motor honey" in it...no STP, or a can of "restore".
 

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84 Bronco, 351w, c6, custom doubler, np208, 5.13’s, TTB44, 9”, locked f/r
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As posted above, change the sending unit above the oil filter. I’ve had a handful of oil pressure scares like that, and 75% of the time it was just the sender
 

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1986 Eddie Bauer 5.0EFI AOD Full length headers Y pipe into single 3" Magnaflow 3" factory exit
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I would be quite concerned about low oil pressure, but the factory guage doesn't really give an accurate measure of what your pressure is, it's more of a dummy guage with its low to high reading.

My assumption has always been at minimum you need 10psi per 1000rpm So 10psi at idle, 20psi at 2000rpms, 30psi at 3000rpm, so when it reads low like yours is, it would concern me.

A cheap oil pressure guage with psi indicators would do a lot to determine where you really are at, but either way, there isn't a whole lot you can do about it if it's caused by wear between the crank and main bearings.

Like others suggested, a 10w-30 or even 10w-40 is thicker oil and may help get you a bit more oil pressure, but when oil pressure starts to drop, it's only a matter of time before you lose a bearing and things start knocking, aka rebuild time, so let's just hope & pray that it's just a bad guage or loose/crusty connection.
 

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1984, 300 L6, smogless, manual 3speed with overdrive.
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I run an aftermarket gauge that reads the lbs of pressure. It’s easy enough for any entry level mechanic to install. I do the same on on the temp with the aftermarket gauge, I know for sure I’m running the right degrees and psi for oil.
 

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1995 Ford Bronco XLT 5.8L
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Mine failed similarly a couple weeks ago.

It would sometimes show 50% (Between "R" and "M" in NORMAL). Then after awhile it would drop to the left, to the "N" in NORMAL, and sometimes all the way into the red.

Keep in mind that in a '95 Bronco's oil gauge only looks like a gauge. The sending unit senses "good" or "bad", only, not actual pressure measurements. The gauge should sit somewhere near the middle when pressure is satisfactory, and to the left (red zone) when pressure is bad.

I replaced the sending unit. Now it always shows between the M and A in the word NORMAL.

I cut opened the old sending unit and found the diaphragm was shot.

It's unsettling to begin imagining all the reasons you might lose oil pressure; bad pump, bad main bearing, clogged sump screen... none of which are particularly good news. It was a big relief that replacing the sending unit corrected the issue. These vehicles are pretty old now, and any diaphragms in sensors have begun to deteriorate with age. Obviously you'll want to verify good oil pressure before driving the vehicle further. In my case there was no change in the sounds of the engine running before vs after the sensor's failure. I ended up having to drive about 100 miles before I was able to get it tested and replaced.

The sending unit is really hard to replace on the 5.8L V8. The biggest issue for me was that I couldn't easily get my hand to contort correctly into the area. It was pretty easy pulling the wire off, and with the right tool removing the sensor would have been pretty easy. But I stopped short of removing it because I knew I could never get my hand lined up right to get the threads started on the new sensor, and I didn't want to be stuck in my driveway with the sensor removed. I took it to a shop and they put it in for me; took them about 30 minutes to get the job done.

If the sending unit is bad, switching from 5w30 to 10w40 isn't going to change the fact that the sending unit is bad. Change oil viscosity if you've actually taken a real oil pressure measurement and have decided that you can eek out a few thousand more miles from the engine by shifting to a thicker viscosity until it finally gives out. But don't do this only based on the value shown on the gauge representing "ok" or "not ok" from the sending unit.
 

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1991Bronco 5.8L, w/95frontclip, 6"Superlift/SuperRunner, Deaver J40 springs, 35x12.5 K&N, 3"Bassani
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As others have stated, the gauge is really a switch (on or off) that indicates whether or not you have pressure above 4.6psi. It doesn't give you an indication of actual pressure. Replace you sending unit and clean the connection and see if the reading corrects. It should fall in the middle of the NORMAL. To be more accurate change the sending unit out for a true mechanical oil pressure gauge so you can measure any fluctuations in oil pressure. You can even keep the OEM switch/dash gauge and wire up a secondary oil pressure gauge with an extension. They are all over the internet and mustang shops., Summit etc. Get some real gauges and never worry about guessing on oil pressure, engine temp or trans temps. just my two cents.
 
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The Tennessee Warden
96 XL, built 357W, E4OD, BW1356, 4.56 gears
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5,221 Posts
As others have stated, the gauge is really a switch (on or off) that indicates wether or not you have pressure above 4.6psi. It doesn't give you an indication of actual pressure. Replace you sending unit and clean the connection and see if the reading corrects. It should fall in the middle of the NORMAL. To be more accurate change the sending unit out for a true mechanical oil pressure gauge so you can measure an fluctuations in oil pressure. You can even keep the OEM switch/dash gauge and wire up a secondary oil pressure gauge with an extension. They are all over the internet and mustang shops., Summit etc. Get some real gauges and never worry about guessing on oil pressure, engine temp or trans temps. just my two cents.
Agreed
 

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1986 Bronco Eddie Bauer 5.0 mostly stock
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As others have stated, the gauge is really a switch (on or off) that indicates wether or not you have pressure above 4.6psi. It doesn't give you an indication of actual pressure. Replace you sending unit and clean the connection and see if the reading corrects. It should fall in the middle of the NORMAL. To be more accurate change the sending unit out for a true mechanical oil pressure gauge so you can measure an fluctuations in oil pressure. You can even keep the OEM switch/dash gauge and wire up a secondary oil pressure gauge with an extension. They are all over the internet and mustang shops., Summit etc. Get some real gauges and never worry about guessing on oil pressure, engine temp or trans temps. just my two cents.
This is good to know…it’s basically just a “stupid light” but in the disguise of a gauge. Makes me want to get one of those Dakota digital or other aftermarket gauge clusters.


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at the very least, go to auto zone, spend 20 bucks on an oil pressure gauge, and hook it up temporarily to get a good reading. My bet is just the sending unit or bad connection (could be bad gauge), but oil should be good. I do also recommend a heavier oil with that many miles. I run a 20W50, but that is with a ZDDP additive for a flat tappet cam.
 

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You’re oil pressure is most likely fine, but your oil pressure switch could be faulty. Or, the wire connection on the switch could be dirty. You can test the switch by grounding the stud on top of it. I believe @miesk5 has a good procedure for testing it, as well as the gauge itself. The switch is a cheap part and pretty easy to replace. It’s located on the engine block, just above the oil filter and toward the front a bit. You should use an oil pressure switch socket to remove it to prevent breaking it.
Yo S,
As MS88Bronc advised.
  • Oil Pressure Always Reads High
  • Circuit.
  • Oil.
  • Pressure sensor.
  • Oil pressure gauge.
  • Oil Pressure Reads Inaccurately
  • Circuit.
  • Oil pressure sensor.
  • Oil pressure gauge.
D1 VERIFY POWER AT LOAD SIDE OF FUSE PANEL
  • Key to run.
  • Measure IP fuse No. 18 (15A) output, using Rotunda NGS Tester 007-00500 or equivalent.
Does voltage read between 10 and 15 volts?
YesNo
GO to D2.REPLACE IP fuse No. 18 and RETEST.
D2 CHECK GAUGE FOR MID-SCALE GRADUATION
  • Key off.
  • Connect the wiring connector to engine block ground.
Does gauge read within mid-scale graduation or slightly above?
YesNo
GO to D3.REPLACE oil pressure sender.
D3 CHECK GROUND CONNECTION
  • Key off.
  • Check resistance of oil pressure switch hex Circuit 31 (W/R) and engine ground, using Rotunda NGS Tester 007-00500 or equivalent.
Does circuit resistance read less than 0.1 ohm?
YesNo
REPAIR Circuit 31 (W/R) as required.GO to D4.
D4 CHECK FLEX CIRCUIT CONTINUITY
  • Key off.
  • Remove instrument cluster and check continuity between the cluster flex circuit and the oil pressure gauge, using Rotunda NGS Tester 007-00500 or equivalent.
Does circuit resistance read less than 0.1 ohm?
YesNo
GO to D5.CORRECT cluster flex circuit as required and RETEST.
D5 CHECK FOR CORROSION/POOR CONNECTIONS
  • Visually inspect the wiring harness connections for corrosion and poor connections.
Is there corrosion? Are there poor connections?
YesNo
REPAIR as required.REPLACE oil pressure gauge and RETEST.

Sender Failure; "Corrosion or faulty electrical connections; If the oil pressure gauge is pegged low after the engine is running, or is pegged high after the engine is running, or if there is intermittent illumination of an oil pressure indicator light, the sender could be faulty. Related Components to Check; All appropriate electrical connections to and from the sender The oil pressure gauge or indicator light; Appropriate fuses (see Shop or Owner’s Manual for fuse layout)..."
by MOTORCRAFT®

Overview in 92-96; "The oil pressure system uses a switch and a fixed resistor; the resistor is attached to the engine wiring harness. A primary magnet, to which a shaft and pointer are attached, rotates to align this primary field, resulting in pointer position. The bobbin/coil assembly is pressed into a metal housing which has two holes for dial mounting. There are no adjustment calibrations or maintenance required for this gauge; Oil Pressure Sender - The oil pressure sender controls the magnetic oil pressure gauge's pointer position. The oil pressure sender (switch) closes under normal engine operating conditions. The oil pressure sender opens with the engine off and no oil pressure..." by former member Steve83

Installation, Sunpro,w/T for stock gauge in an 86
Source: by Sixlitre (Malcolm H, Eddie Bauer) at 1986 Ford Bronco Mechanical Oil Pressure Gauge & Keep Stock One Too pictures, videos, and sounds | SuperMotors.net

 

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Check your connection, if that doesn't fix it, and you check your sending unit and it's bad, now you're spending money. Either get a new unit, a gauge, or both. If you add a gauge, you'll know exactly where you are.
Back in the 90s, we had a '79 f250 crew cab, didn't even know how many miles it had on the 400m. Gauge wasn't reading, I put in an aftermarket gauge.
With either 10w30, or 10w40, it was maybe 15lbs at idle, and 18lbs, maybe 20lbs anywhere from about 1800rpm and up. Using 1qt of 80-90 bumped it to around 20lbs at idle, 30lbs or more above 1800rpm. Drove it like we stole it for several years, until someone rammed into it parked in front of a friend's, and diamonded the frame.
 

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95 XLT 5.8L
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Discussion Starter · #17 ·
As others have stated, the gauge is really a switch (on or off) that indicates whether or not you have pressure above 4.6psi. It doesn't give you an indication of actual pressure. Replace you sending unit and clean the connection and see if the reading corrects. It should fall in the middle of the NORMAL. To be more accurate change the sending unit out for a true mechanical oil pressure gauge so you can measure any fluctuations in oil pressure. You can even keep the OEM switch/dash gauge and wire up a secondary oil pressure gauge with an extension. They are all over the internet and mustang shops., Summit etc. Get some real gauges and never worry about guessing on oil pressure, engine temp or trans temps. just my two cents.
I’m an absolute noob here. Would you maybe be able to link me a guide of some sort or something of that nature with some pics maybe that details the process you described because frankly I don’t even know where I would start here, I’m 19 and I only started tinkering with this stuff when I bought the truck like 6 months ago, so I’m still kind of at the point where when something needs to get fixed I just take stuff apart, see what happens, and then put it back together with new parts lmao
 

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Yooo where did you get these gauges from and how did you install them? Is there any kind of guide or anything out there because I’m still really new to this crap
those are autometer gauges, can be had from just about anywhere, or online.

to install, you mark your locations, use a hole saw (easiest way) and punch the hole. slip in the gauges, intall the mount nut from the back and tightend down (easiest to do with dash out, not required though.)

and run your oil lines or electrical lines as needed. if you are backlighting, run a wire from your fuse box or dash lighthing panel depending on how you want things working.
 
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1986 Bronco Eddie Bauer 5.0 mostly stock
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Yooo where did you get these gauges from and how did you install them? Is there any kind of guide or anything out there because I’m still really new to this crap
You can get those gauges all over the internet in several different flavors, you can even get them at your local autozone or oreilly...do some research. The biggest decision you'll need to make is if you want mechanical or electronic gauges. The mechanical style will literally have a copper or nylon tube running from your engine, through the firewall, and into the dash (or wherever you mount the gauge), whereas an electronic will have a sending unit you have to install into an oil port then a wire runs to the gauge. For precise reading the mechanical is hard to beat...but you have to be very careful of how you route that line, if it cracks or gets kinked or gets a hole in it somehow, youll be shooting oil everywhere, i have gone the route of electrical in my last couple of builds just because it was "neater" those dang nylon hoses can be a pain in the rear.

I had my fuel pressure gauge mounted on my cowl in my race car...was easy to see and didnt worry about a fuel leak inside the cabin if something happened. Plus it was an NHRA rule...if you had a fuel pressure gauge you had to have a diphragm adapter to run the gauge in the cabin...and those were expensive and I'm a cheapskate.
 
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