Oil Light...FSM no help TS, Anyone?

[Schroder]

So, for the last year or so, my oil light would come on once in a while, just flicker a few seconds, or stay on a few seconds, and it usually meant the rig was a little low on oil (Wife drives it as primary vehicle, and tells me anytime this happens).

More recently, it has come on and stayed on for longer periods, like 5, 10, 20 minutes at a time, at low speed, Hwy speed, around town, accelerating, declerating, whatever. I did the obvious oil level check and it is fine, just slightly above the mid-point between when you should add, and when it is full on the dip stick - that is early in the morning prior to start, and even just 5 minutes after running it.

So, after searching the FSM for ways to TS this light, I find nothing obvious, outside of the fact that there is an oil level indicator switch, as well as an oil pressure indicator switch, either of which could go south at 156K (1996 FJZ80) mark. I am thinking, based on the exploded diagrams, that the oil pump is mechanical on these things, and likely does not go south often.

I am running M1 5W-30 since I have owned it (35K), and it was running Redline prior to that, and very well maintained by a single owner.

Any obvious things I am missing here? No CE light yet, nothing else related.

 

[Romer]

Werner, when you say it usually meant it was a little low, how low was it? This would concern me if the light came on really being low multiple times. How often do you check it?

I am personnaly not familiar with where the switch and wiring is locates, but my first look would be at the wiring and the connector in case it is loose or dirty. Not an expert in these areas so I am sure another will chime in.

 

[Schroder]

I check it every couple of weeks, but when life got busy, it would go longer. It has traditionally used a little oil between changes. When I would add oil, it would be a quart-n-half low. Otherwise, I caught it between changes.

 

[Schroder]

Today is a great example. Going up the hill (I-70West) from the house, it comes on for a few minutes on the drive up 6th avenue, then goes away until we stop in Evergreen. It comes on again on the way down I-70, and goes away half way home.

I check oil when I am home again, and it is just a smidge below midpoint between full and add on the dip stick.

 

[MoGas]

Keep it at the "Full" mark and see what happens. I bet your level switch is going bad. When I had a leak, my light would come on @ exactly the "low" mark. All that light comes on for is the level, not pressure or pump failure.

 

[Schroder]

Thanks for the tip. Curious, where did you find out what is exactly tied to the dash light? I figure if I studied the wiring diagram long enough, I could find out, just wondering.

I will fill it up and see what happens.​

 

[Schroder]

So, after thinking about your response, I remember being under my rig one time, thinking to my self ..."My, what a big oil pan you have....."

SO, even with the oil level showing at just under half way inbetween 'add' and 'full', I bet you could put a quart in, and still be under the full line.

Sure enough, having put in just under 1.5 quarts in this thing, the oil level on the dip stick (after it settled for some time) it sits right about 2mm below the full line! Gee whiz this thing is thirsty.

Also, running a K&N Oil filter, so factoring in the additional oil capacity within the filter, then the reduced overall oil level when the system is pressurized, may very well bring me to a point of triggering the indicator light.

I asked the wife to tell me if it comes on again in the next few days. I will update the thread when we find out anything.

 

[nakman]

Mine comes on if I'm more than 1/3 the way below "full" on the dipstick, and that's after taking the sensor out and bending it down a little bit, was a tad more touchy before. Here's the thread you want to read: https://forum.ih8mud.com/80-series-tech/24818-low-oil-light.html

 

[Schroder]

Thanks for the link...Been looking everywhere.

 

[Elijah]

Another thing to keep in mind, the oil level should be checked right after the vehicle is turned off. If you check when the engine is cold or before starting the dipstick should read over the full line.

 

[Schroder]

Yeah, interesting you state that, I ran it warm this morning to do a final check prior to leaving for work today. After shutting it off, and only waiting a 2 minutes, it showed at the mid point again, and that was after having added about 1.75 Qts since this thread was started.

 

[corsair23]

My tip FWIW...

Fluid levels drive me nuts

Next time you do an oil change, fill the 80 up with 8qts and let it sit. Check the level cold and see where YOUR rig shows the oil level at in that condition. Record that in your FSM, memory bank, whatever.

Now get the engine up to operating temp (15-30 minute drive), shut down the engine, and check the oil level and note where YOUR rig shows the oil level at in this condition.

Now you know (given a known 8 qts in) what YOUR rig shows/reflects on the dip stick as the "proper" level. I've read enough threads on aftermarket dipsticks etc. to realize that fluid levels are in many cases rig dependent.