Intermittent Oil Light coming on. (1 Viewer)

[MauiUZJ]

The Low Oil Pressure light has come on several times recently. First couple times it was just a flicker, then on for a few seconds at a time. Then today it stayed on for several minutes. Oil level is good, and the engine sounds healthy. Oil Pressure Gauge always reads good.

Guess I need to get a good electrical wiring diagram and trace some wires to see if it is the switch, or perhaps a short to ground. It seems to happen at highway speeds.

 

[ppc]

View attachment 3309330
The Low Oil Pressure light has come on several times recently. First couple times it was just a flicker, then on for a few seconds at a time. Then today it stayed on for several minutes. Oil level is good, and the engine sounds healthy. Oil Pressure Gauge always reads good.

Guess I need to get a good electrical wiring diagram and trace some wires to see if it is the switch, or perhaps a short to ground. It seems to happen at highway speeds.

That is not an oil pressure warning light but is a oil level warning light. Check the oil level on the dipstick to confirm it is OK. The level sensor on the side of the oil pan is known to give false readings as it gets old. Some Have tried to remove and clean but with limited sucess.

 

[ToyotaMatt]

View attachment 3309330
The Low Oil Pressure light has come on several times recently. First couple times it was just a flicker, then on for a few seconds at a time. Then today it stayed on for several minutes. Oil level is good, and the engine sounds healthy. Oil Pressure Gauge always reads good.

Guess I need to get a good electrical wiring diagram and trace some wires to see if it is the switch, or perhaps a short to ground. It seems to happen at highway speeds.

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[flintknapper]

That is not an oil pressure warning light but is a oil level warning light. Check the oil level on the dipstick to confirm it is OK. The level sensor on the side of the oil pan is known to give false readings as it gets old. Some Have tried to remove and clean but with limited sucess.

This ^^^^^

Check your oil level.

 

[jaymar]

I’ll get that when the oil level is marginal. Incline or quick stop can affect it. Or acceleration. Driving around for a while can make it go off; presumably the oil is heating up and expanding and covering the sensor.

 

[LongDuck]

Magic Genie says; "Time to change your oil, Master!"

(*Note, she's reading the FSM, as there wasn't a Mud Forum back in those days...)

 

[bhsdriller]

I get it when it's cold but goes away. Check your oil level

 

[Mjones]

View attachment 3309330
The Low Oil Pressure light has come on several times recently. First couple times it was just a flicker, then on for a few seconds at a time. Then today it stayed on for several minutes. Oil level is good, and the engine sounds healthy. Oil Pressure Gauge always reads good.

Guess I need to get a good electrical wiring diagram and trace some wires to see if it is the switch, or perhaps a short to ground. It seems to happen at highway speeds.

Mine does the same thing and dipstick shows oil level is fine. The warning light on mine seems to appear more often as I approach 2.5k-3k miles past an oil change and then goes away after the oil change and then repeats the cycle. I used to leak enough and still burn enough I was having to add a quart or two between oil changes. But will some replaced seals and no little leaks it's just a slow burn. So at most adding 1/4 to 1/2 quart between oil change intervals. I'm guessing just old grungy oil level sensor.

 

[flintknapper]

I’ll get that when the oil level is marginal. Incline or quick stop can affect it. Or acceleration. Driving around for a while can make it go off; presumably the oil is heating up and expanding and covering the sensor.

The oil level sensor is a small 'float'at the end of an arm (see below).

IF the actual oil level (per the dipstick) is correct then pulling the sensor and cleaning it can free up a 'sticky' float.

Most sensors are leaking oil from the seal anyway, so a good time to inspect. I can guarantee you the seal is hard as a rock by now and dried out.

 

[-Spike-]

The sump holds more than 8 quarts of oil. When it's a quart low it will be hard to tell on the stick. The oil level sensor is sensitive, and will light up even though the stick reading looks fine. Add a quart and that should fix it.

 

[jaymar]

The sump holds more than 8 quarts of oil. When it's a quart low it will be hard to tell on the stick. The oil level sensor is sensitive, and will light up even though the stick reading looks fine. Add a quart and that should fix it.

Until, in my case, it leaks out two days later.

 

[MauiUZJ]

Thank you.

That is not an oil pressure warning light but is a oil level warning light. Check the oil level on the dipstick to confirm it is OK. The level sensor on the side of the oil pan is known to give false readings as it gets old. Some Have tried to remove and clean but with limited sucess.

Magic Genie says; "Time to change your oil, Master!"

View attachment 3309486
(*Note, she's reading the FSM, as there wasn't a Mud Forum back in those days...)

LOL, first thing I did was to check the oil level. It’s good. Wish my 80 came with a FSM. I only have a FSM for my hundred series.

 

[BILT4ME]

Thank you.


LOL, first thing I did was to check the oil level. It’s good. Wish my 80 came with a FSM. I only have a FSM for my hundred series.

Look /\ /\ /\ above to the RESOURCES section and download the one for your truck!

 

[jaymar]

Thank you.


LOL, first thing I did was to check the oil level. It’s good. Wish my 80 came with a FSM. I only have a FSM for my hundred series.

You can also get printed copies, for $$.

 

[-Spike-]

Thank you.


LOL, first thing I did was to check the oil level. It’s good. Wish my 80 came with a FSM. I only have a FSM for my hundred series.

It may look good, but if adding a quart fixes the light, you can infer what the problem was.

In my experience, when the oil level sensor has a problem, it doesn't work. If it is lighting up, it's almost always because it is working, and doing its job correctly. Especially when it's fine after an oil change but starts coming on after you get some mileage on it- obviously the oil level has gone down.

The reason it comes on at highway speeds is because with the engine revving steadily, the oil is being pumped to the top of the engine and doesn't get down to the sump as fast, and so the sensor is triggered.

 

[baldilocks]

It may look good, but if adding a quart fixes the light, you can infer what the problem was.

In my experience, when the oil level sensor has a problem, it doesn't work. If it is lighting up, it's almost always because it is working, and doing its job correctly. Especially when it's fine after an oil change but starts coming on after you get some mileage on it- obviously the oil level has gone down.

The reason it comes on at highway speeds is because with the engine revving steadily, the oil is being pumped to the top of the engine and doesn't get down to the sump as fast, and so the sensor is triggered.

After reading your posts someone with no or little automotive experience would think that the dipstick is unreliable and should be disregarded in favor of the light. My light has never illuminated in the 7 years I’ve had my 80 and per the dipstick, the oil is very near one quart low at the 5k oil change. So, if the dipstick reads full but the light is on oil should be added until the light extinguishes?

In my world the oil level sensor does not exist as this 80 is the only vehicle I’ve ever owned with an oil level sensor which I perceive to be fluff.

 

[MauiUZJ]

The oil level sensor is a small 'float'at the end of an arm (see below).

IF the actual oil level (per the dipstick) is correct then pulling the sensor and cleaning it can free up a 'sticky' float.

Most sensors are leaking oil from the seal anyway, so a good time to inspect. I can guarantee you the seal is hard as a rock by now and dried out.



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Thank you for the very detailed and awesome post. This is the first FZJ80 I’ve ever had. I wonder if my FJ80 had a oil level warning system. It’s been 8 years, and I don’t remember if it had one. Super glad this is all it is, and maybe the sending unit needs a little love.

 

[MauiUZJ]

It may look good, but if adding a quart fixes the light, you can infer what the problem was.

In my experience, when the oil level sensor has a problem, it doesn't work. If it is lighting up, it's almost always because it is working, and doing its job correctly. Especially when it's fine after an oil change but starts coming on after you get some mileage on it- obviously the oil level has gone down.

The reason it comes on at highway speeds is because with the engine revving steadily, the oil is being pumped to the top of the engine and doesn't get down to the sump as fast, and so the sensor is triggered.

I suppose I should add that by “looked good” I meant the oil level was a hair below the middle of the dipstick when parked.

Considering this 30 year old rig was parked most of the last 10-12 years, I have been checking all my fluids religiously several times a week.

 

[MauiUZJ]

After reading your posts someone with no or little automotive experience would think that the dipstick is unreliable and should be disregarded in favor of the light. My light has never illuminated in the 7 years I’ve had my 80 and per the dipstick, the oil is very near one quart low at the 5k oil change. So, if the dipstick reads full but the light is on oil should be added until the light extinguishes?

In my world the oil level sensor does not exist as this 80 is the only vehicle I’ve ever owned with an oil level sensor which I perceive to be fluff.

Of course you always trust the dipstick first and foremost. I never had an oil level light before unless my 92 had one, but if it did it never came on.

 

[-Spike-]

I suppose I should add that by “looked good” I meant the oil level was a hair below the middle of the dipstick when parked.

Considering this 30 year old rig was parked most of the last 10-12 years, I have been checking all my fluids religiously several times a week.

On my truck, when the oil pan is at full capacity, such as after filling it after an oil change, the oil is at the very top of the hashed section of the dipstick. You are probably not at risk of pumping air on the road, but I wouldn't take your truck off road if I were you. And I'd say again that your oil level sensor is working exactly as intended- you are technically low on oil.