low oil pressure

[ryan_88]

hi, i just got a 2001 xlt supercab the other day. its a V6 4.0L. it has 135,000 miles on it. yesterday i changed the oil. i put in 5 quarts of mobil 1 fully synthetic 5W-30, and used a motorcraft 820S filter. today, i go to start it up, and the check gauges light comes on and the pressure is on low. any ideas? thanks!

 

[MAKG]

The pressure spec is 40 PSI at 2000 RPM. If you don't know either of those numbers, you don't know the oil pressure is low. The stock gauge simply doesn't tell you that.

A big hint is that the "check gauges" light is on.

 

[ryan_88]

so you're thinking its a bad gauge rather than actually no pressure? it just seems weired because i changed the oil yesterday, it makes me think i screwed something up.

 

[ryan_88]

also, is the motorcraft 820S the right filter to use? everywhere i look says it is the right one, but the one i took off was just 820, and was shorter than the 820S.

 

[85_Ranger4x4]

Have you checked the oil level since you changed it? Did it start doing this right after you changed it (assuming you started it checking for leaks) or just this morning?

 

[ryan_88]

i changed it yesterday afternoon. last night i drove about 1/4 of a mile, and the pressure dropped to low, and the light came on. i shut it off, checked that the cap was tight, started it back up and all was well. drove for another mile and that was it. today, started it up and pressure was all the way down, light was on. i shut it off, checked cap, filter, plug, all are tight. i checked the oil level then, and it was fine. i just checked it again now, and it is still fine. there are no signs of leaks underneath either.

 

[ryan_88]

i think i'm going to try and replace the oil pressure switch. however, i cant seem to find it for the life of me. the haynes manual says its located at the oil filter. i dont seem to see it there any ideas?

i also found these, but i can't tell where that is.

 

[85_Ranger4x4]

You might try a different oil filter, since it happened right after you changed it seems as thought it was something that happened related to your oil change.

 

[ryan_88]

i changed the filter last night, still no pressure (so says the gauge)

 

[ryan_88]

ok, so i took it to the shop today. turns out it was the oil pressure switch. the mechanic said it was located near the harmonic balancer just below the AC compressor. thanks to all for your help!