Oil Level

[LCAM-01XA]

Racer30, if you have access to the side of the oil pan you should be able to install the OEM Ford sensor, it screws in from the outside and the nut for it can be welded on the outside as well. However it may be a good idea to wait till I try it first, as if I screw up I will simply weld up the oil pan like it never happened, which may not be easily doable in a motorhome.

Jaluhn83, I'm not sure how exactly the sensor works, it's not really a float but I don't know what it really is. The EVTM is not very descriptive there, only says the sensor grounds when oil gets about a quart and a half low. My guess is at that time the sensor gets exposed to air, but what does to it to cause it to ground I have absolutely no idea. And the more I look at it the more it seems they use the sensor just as a switched ground for the relay's pull coil, while the actual warning light is hooked up to the load circuit of the relay, and the only reason to even use a relay is cause of the timing circuit which waits 5 min after power has been cut off before resetting relay (this done to allow for oil to drain back in the pan). I'll know more when I get my hands on a sensor and a relay with timing circuit attached.

 

[jaluhn83]

It's based on capacitance - the actual sensor is just probes with exposed metal contacts a short distance apart. The capacitance (ability to store charge, ie act like a capacitor) changes significantly whether is oil or air between the 2 probes. You need some external circuitry to measure that and compare it to a predetermined value to decide if there's oil there or air. This is probably integrated in that "relay" unit.

 

[antiqueford]

It's based on capacitance - the actual sensor is just probes with exposed metal contacts a short distance apart. The capacitance (ability to store charge, ie act like a capacitor) changes significantly whether is oil or air between the 2 probes. You need some external circuitry to measure that and compare it to a predetermined value to decide if there's oil there or air. This is probably integrated in that "relay" unit.

That's not what it sounds like. It is either open or grounded. If there's circuitry to be had, it is within the sensor body.

 

[LCAM-01XA]

On the diagram itself it's called a "low oil level switch" and is marked as "closed with low oil level". Schematics of its internals operation also portray it as a switch, and nothing more. Circuit operation description says "the low oil level relay determines whether the low oil level sender switch is grounded (oil low) or not grounded (oil not low)." Physically the thing is a hollow tube wit three long slots cut (120 degrees apart) in its wall thru which oil enters. Thru the same slots it is visible something like a plunger or float, and if you shake the sender said plunger/float will wiggle around and touch the walls of the tube. The reason I said last time it's not really a float is because it mounts sideways and also spins as you install it so in one pan it may end up with a slot on the top side and if moved to a different pan it may have a slot on the bottom, it's never really consistently in one and the same position. Unlike the aircraft sensor OldBull found, which is a normal float. Next time I'm raiding a U-Pull-It yard I'll make it a point to grab a few of these senders/switches and dissect one of them - you may very well be correct that it's some sort of capacitance sensor, but I'd like to see its inner workings for myself.

 

[The Warden]

I didn't see this mentioned in the discussion, so please forgive me if I missed it...but, when one of these engines is actually running, how much oil is in the pan? The pan obviously wont' be empty, but it's going to be lower than it would be when the engine's not operating, because some of the oil's being pumped into the galleries, up to the valvetrain, etc. Seems to me that that may factor into the height that you're putting the sensor at, but maybe that's already been addressed and I just missed it?

 

[antiqueford]

^ Good point!

I would guess about 2qts would be in the galleries/ draining back at a time? Either put the sensor in another inch lower or only activate it without the engine running. Key on, engine off, maybe can tie it in with brake and ABS lights somehow? Or ground it when cranking, and have the relay wired to give the light 12v when the sensor reads low.

 

[jaluhn83]

Physically the thing is a hollow tube wit three long slots cut (120 degrees apart) in its wall thru which oil enters. Thru the same slots it is visible something like a plunger or float, and if you shake the sender said plunger/float will wiggle around and touch the walls of the tube.

Sounds like some sort of a float sensor, disregard all my ramblings. My guess would be there's a magnet in the top of the float and a weight at the bottom so it floats magnet up - when the level gets low the magnet closes the reed switch inside. Or something like that.... If it's got a float it's not capacitance based.

Tim, I've thought about that, was figuring there'd be 1-2 qts circulating so ~6-7 left in the pan. Was thinking I'd try to set it up to trip with ~3 qts left in the pan.

 

[LCAM-01XA]

Warden, yes it was mentioned by Jaluhn83, but it completely slipped my mind. So I guess we really need a guinea pig, someone who has an old IDI pan laying around - fill said pan with water till about 6" below pan rails then dump 2qts of water out, and measure how far from the pan rails the new level is. Any volunteers? lol

Antiqueford, a level sensor that does not read oil lever as you drive is essentially useless. It is my unofficial policy to never even shut the engine off while on a long road trip (sometimes that means running it 24/7 for 2-3 days), I wanna know if I'm losing oil while I drive.

Jaluhn83 that float setup makes perfect sense. I'll still get medieval with one tho, or it will forever bug me.

 

[antiqueford]

I don't do all that many 1000+ mile hauls, so it's unlikely that with normal oil consumption, my oil level would suddenly drop. If it did drop more than 4 qts in 1000 miles, it would be cause for the "oh ****" light to come on anyway (hole in the pan, or worse). For me, the level switch would be a means to remind me that I've been neglecting to top it off regularly.

 

[jaluhn83]

I'm going to try the filling thing once I get my pan off here in the next few weeks. I'll make sure and take pictures of what I find up doing.

 

[LCAM-01XA]

I don't do all that many 1000+ mile hauls, so it's unlikely that with normal oil consumption, my oil level would suddenly drop. If it did drop more than 4 qts in 1000 miles, it would be cause for the "oh ****" light to come on anyway (hole in the pan, or worse). For me, the level switch would be a means to remind me that I've been neglecting to top it off regularly.

Punching a hole in the pan is not something I'm really worried about, I've gone to great lengths to ensure that is not a viable threat My concern is a slower leak, like a seal partially letting go, something that's not serious enough by itself to sideline you but if left unnoticed can eventually mess things up. Well that, and the neglect thing you mention, guilty as charged there too

I'm going to try the filling thing once I get my pan off here in the next few weeks. I'll make sure and take pictures of what I find up doing.

Actually if you gonna do that here's a better idea - measure how far below engine block rails the full mark of the dipstick sits, fill the pan to that level, then dump a gallon out (2qts for the low mark and 2 more for circulation volume while running), and measure how far below pan rails the level is now. Quick and simple and for the most part accurate.

 

[OLDBULL8]

[Warden, yes it was mentioned by Jaluhn83, but it completely slipped my mind. So I guess we really need a guinea pig, someone who has an old IDI pan laying around - fill said pan with water till about 6" below pan rails then dump 2qts of water out, and measure how far from the pan rails the new level is. Any volunteers? lol/QUOTE]

OK, I'll be the "PIG". Got two engines torn down now with the pans off. Soon as I get my camera battery charged I'll do that. I'll try and tilt the pan a little to mimick the engine installed, along with laying it flat.

I don't need an oil level sensor in my PSD, when it runs low on oil it shuts down cause the %#$* injectors won't fire anymore.

Check back about 8:00 PM tonite, Ill post the info.

 

[The Warden]

So I guess we really need a guinea pig, someone who has an old IDI pan laying around - fill said pan with water till about 6" below pan rails then dump 2qts of water out, and measure how far from the pan rails the new level is. Any volunteers? lol

How sure are we that 2 quarts is what you have in the engine when she's running?

Here's an idea, if we're not sure and if the "FULL" level is below the rotating assembly (I've never had an oil pan off one of these engines, so I'm not sure), and if there's someone who's about to do an oil change and who'd be willing to try this. With the engine off, check the oil level, and bring it up to Full. Then, start the engine, give it a couple of minutes to make 100% certain the oil galleries are full, then pull the dipstick again while the engine's still running. When you stick it back in after wiping it, pull it out as fast as you can and hopefully you won't get too much draining oil on the dipstick...and, see if the level's on the dipstick. If not, then add some cheap oil into the crankcase, then check again. Keep doing that until you get some oil on the dipstick, keep tabs on exactly how much oil you've added, and that should tell you definitively how much oil's in the crankcase (keep in mind to factor the difference in level between where you stop and the "FULL" mark). You'll want to immediately drain that oil out...which is why I suggested someone who's about to do an oil change anyways.

Just a thought

I don't do all that many 1000+ mile hauls, so it's unlikely that with normal oil consumption, my oil level would suddenly drop. If it did drop more than 4 qts in 1000 miles, it would be cause for the "oh ****" light to come on anyway (hole in the pan, or worse). For me, the level switch would be a means to remind me that I've been neglecting to top it off regularly.

I remember once, shortly after I got my hands on my truck...I was driving down the highway and I started hearing a ticking sound. I checked my oil pressure gauge to find it was reading 20 psi I pulled over and popped the hood...the dipstick was completely dry and there was oil all over the firewall. Turned out the plastic line going to my mechanical oil pressure gauge had failed, and I was pumping oil out of the block. Fortunately, no ill effects from that...I've put almost 70K miles on the truck since then with no problems. This is a pretty extreme example, but it helps demonstrate the need for something like this...even if you're religious about checking oil level at every fuel-up (I am), you can still have something go wrong, and it'd be nice to know something's going on before it's too late. Same logic with a low coolant level alarm setup...

 

[LCAM-01XA]

OK, I'll be the "PIG". Got two engines torn down now with the pans off. Soon as I get my camera battery charged I'll do that. I'll try and tilt the pan a little to mimick the engine installed, along with laying it flat.

I don't need an oil level sensor in my PSD, when it runs low on oil it shuts down cause the %#$* injectors won't fire anymore.

Check back about 8:00 PM tonite, Ill post the info.

Excellent, thank you very much for this! To make it easier on you just do what I suggested in my last post - measure distance between dipstick full mark and block rails, fill the pan to the same level below its rails, then dump a gallon (milk jug, ice-tea jug, coolaid jug, etc.) out and see how low water sits now.

 

[OLDBULL8]

Well here we go with all the measurements on the oil pan. Gonna take 3 post for the pics.

1st ---Depth of pan at rear deepest point. 11"
2nd---Depth at front of pan. 6-1/2"
3rd---Depth at center top of slope from rear. 5-1/2"
4th---Bottom of slope 11", top of slope 14" from rear.