Hey guys!
New to the forum, I just got a 2001 F150 4.6L.

I have a question about the low oil sensor: the sensor comes on when the oil level is still about 1/2 way between the low and full marks, and when it does come on my oil pressure guage doesn't read anything. I have read somewhere that the dash oil pressure guage is not really a guage? ...it's an all or nothing reading? The engine doesn't clatter when this happens, so I assume that it has some oil pressure. So when the light is on, does it overide the gauge?

This has happened twice now. Both times I've added about 1L of oil and everything is fine. So now I'm wondering where the oil is going? It doens't leak, and I haven't seen any blue smoke?

 

xl,

couple of things here. first off your truck DOES NOT have a "low oil level warning" device!

what it DOES have is a "low oil presure warning device"! it works like this: when the oil pressure gets low becuase of lack of oil in the pan or a faulty pump, the oil pressure will drop, if it drops below the level of the oil pressure sending unit's operating range the guage will drop and at the same time turn on the oil light as a warning.

You are correct the low oil pressure sending unit is basicily an all or nothing unit, anything above 6-10 psi "it's happy" and sends a voltage to the pcm and your guage to put them in the normal range.

The fact that your truck (4.6L especially) can be really picky about what oil you use, my bro has that motor in a Lincoln and will burn a quart to 1000 miles (no smoke) just goes away. He switched to fords oil and weight and never uses a drop (go figure) On mine I use Mobile One and never use a drop. "Just for what it's worth"

Now some engines have more oil capacity in there pans than others. So when the oil level gets low and you brake to come to a stop, all the oil can be forced to the front of the pan for a few seconds (depending on your braking period) and the oil pump gets starved for oil and will not produce pressure and turn on the warning light and kill the guage, this should return after the pump picks up oil again, a second or two after your stop.

If this is whats happening! Of coarse the best thing to do is get it to were it's doesn't use that quart of oil.

Hope this has been informative and not too long.

Gene

 

thanks Gene!

yes, it was helpfull, and it's got me thinking about a few other things. I guess I should read the owners manual a little more closely
The idiot light looked like the low oil level light on my Mustang.

The "low oil pressure light" came on again this morning. And again, the engine did not clatter as if it had no oil pressure at all. After turning the engine off, then back on again, the oil pressure came back and everything seems fine.
So I guess my new question is what's causing this?
-faulty sending unit
-oil pump
-or simply the wrong grade of oil?

-Don

(p.s. does this forum have PM's?)

 

Hey Don,

I would just go to your parts store and get a new sending unit. They don't cost much $ 10 or $ 15 bucks and not to bad to get to.
Location is right next to the oil filter on the block, open or boxed end wrench is all that is needed to change it out.

Good luck and lets us know if it cures your problem!

Gene

 

again, thanks Gene!

This weekend I'll be changing the oil and filter to 10W30 Syn.
If it's that cheap for a new sending unit, then I'll be doing that at the same time.

 

I have a similar problem here; when the outside temperature cools off my oil pressure light comes on and the gauge drops. I have no problems all summer long but as soon as the whether starts cooling off the behavior occurs. Once things warm up (either the engine our the outdoor temperature during the day) everything works fine. I have a feeling that it is the sensor but I wanted to solicit other's thoughts.

Thanks

 

Has ford ever made a f-150 with a low oil level light? My old 93 explorer limited had the low oil level light, as soon as oil dropped to add mark the light would come on.

I really miss that in my f-150, today i checked the oil and it wasn't even on dipstick! In the explorer it would have told me with the light.

 

For what it is worth, replacing the sensor fixed the problem!

 

Where is that sending unit anyway? I posted about an identical problem a month or so ago but still haven't fixed it...yes I'm lazy.. I called AZ, but they said the part was 'unavailable' to them. Still need to get one and replace it for peace of mind. I've not had the problem when the engine is warm/hot.

 

The oil pressure switch is on the back side of the filter housing.
Takes a deep metric socket and about 2 foot extension.
The connector has a lock tabs that are pressed inward, then pull the connector off.
I just added an oil pressure gage sending unit, so know how it all goes.