Low oil pressure 93 ATX

[CheckerSHO]

This 93 atx has been a big problem so far in the few months i've owned it. At this point, the main problem i am having is oil pressure. When i first got the car, the oil light would flicker at times at a stop when hot. So i do the usual thing and replace the rod bearings. There was no engine noise at that time besides timing chain tensioners(repaired that too-was streched chains, also cleaned tensioners out while they were out). I didn't look at the main bearings...i probably should have though. because the light still comes on at idle when hot. So i put a manual gauge on it and its dropping below the spec( 12.5psi hot idle). Has anyone on here run into bad oil pumps on these motors? Just trying to gauge which would be more likely before I tear back into this thing. If i have to do the oil pump it will be the 4th time that timing belt has come off in 2 months heh.

 

[93rev2sev]

What kind of oil are you using?

5W20 is too thin for these motors when new, let alone after 100,000 miles.

Edit:
Did you check the clearances on the new bearings?

 

[Phoenix]

Low oil level + old ass oil can cause that on wear'd bearing , but you did them. Happens to me all the time in my green winter beater, when light comes up , I know its time to add oil.

Id check these things

Wire that goes to the oil pressure sensor (wiggle , check corrosion)
The oil pressure sensor itself
If that gives no results , oil change with 5w30 (Castrol to name one) AND the filter , Already seen a failed filter giving me that crap.

 

[SHOtimer]

I echo the above posts, my first thought was what grade oil are you running, and my second was how old is it?

5w30 or 10w30 is best, depending on your climate. Are you running synthetic? If so, that could be your issue, might need to change to conventional - Castrol works great.

Let us know and we can go from there.

Doug

 

[CheckerSHO]

I'm running 10w30 motorcraft oil(not synthetic). The oil is new(i did the rod bearings like 400 miles ago). I didn't check the clearance on the new rod bearings, because the old ones didn't look like there was a problem with them so i just swapped them out. The engine was neglected in its prior life(run 15,000 miles on same oil best i can tell). I ruled out a sender problem because its got a manual gauge on it as we speak(just to verify the low oil pressure)

 

[ViPER1313]

If I'm not mistaken 12 to 13psi of oil pressure at hot idle is normal. The pressure switch shouldn't light up unless there is less than 6psi of pressure. Sounds to me like the pressure sending unit for the idiot light is dead.

 

[Storm-Chaser]

Yeap - the low [ OIL ] pressure idiot light should illuminate when the pressure drops below 6 psi.

Conversely - where on the block is the second gauge measuring pressure from? Did you install a "T" where the OEM pressure sending unit [was], or are you measuring oil pressure from a different source-point on the block? Is the aftermarket gauge mechanical or electrical?

 

[CheckerSHO]

I removed the oil pressure sender and put a mechanical gauge in its place. Its a temporary one...like its run up to the windshield lol. Its a professional one, the heavy line guy at my work let me borrow it.

 

[93rev2sev]

If the guage registers at least 6PSI at idle, and it climbs rapidly with RPM, I would be ok with that.

 

[Storm-Chaser]

Sounds pretty textbook to me, and I think others will agree that your oil pressure sending unit is at fault. Replace it and the low OIL pressure light issue should be resolved.

For those trying to rectify a low [ OIL ] pressure light at idle, this is how it is done. First, validate whether the condition actually exists (ie. oil pressure is low), by checking the pressure at the original source using a good quality mechanical gauge. Ideally you would like to use a brass tee-fitting so the pressure reading from the mechanical gauge can be directly compared to the flickering idiot light.

While there are other places on the block where an oil pressure gauge/gauge sender can be tapped, the oil pressure (and related gauge reading) varying throughout the engine.

I removed the oil pressure sender and put a mechanical gauge in its place. Its a temporary one...like its run up to the windshield lol. Its a professional one, the heavy line guy at my work let me borrow it.