Engine Oil Warning Light - how low?

[KWAWD]

I've a question about the oil warning light on the dash; at what level does it come on?

I was filling the oil the other day and I accidently drove the car with low oil before I realised it, i.e.: the oil was slightly less than half way between the high and low marks on the stick.

But there was no warning light on the dash. How low does the level have to get before the light would come on? Is the warning light a reliable indicator of too low oil pressure?

[leadfoot6]

You have nothing to worry about as long as what you described is a "one off" situation, and the indicated oil level was actually as how you described it.

The oil would need to be lower than the lower dot, or you would need to be giving the engine a "big rev"(oil areation), or cornering/braking hard enough that the oil pick up was sucking air due to underfilling or leakage.

A brief "flash" of the light would be mild cause for concern, which would require prompt investigation.

A longer illumination would be of greater concern, requiring even quicker investigation.

The warning light is not conclusive proof of true low oil pressure, but it would be strongly advised to take heed of the readings.

What is more important is how you managed to drive the car before refilling the oil and double(triple) checking the added quantity.

[Spetz]

I have heard 15psi is when it goes off.
But I don't know how true that is

[KWAWD]

Its a long story, but briefly: I started the oil change without realising I didn't have enough oil on hand to finish. I was going to buy some oil the next day to finish but then there was a family emergency when my mum went into hospital for a week and I just forgot all about it while that was going on.
Later I drove the car three times (about 200 k's) before remembering.

What I find surprising is that the oil/engine light never came on. Never saw it flickering either.
When is it supposed to come on?

Is there any risk of damage while it was low like that? How would it behave if there was any damage?

[KWAWD]

btw, pretty annoyed with myself about it!

[leadfoot6]

I've a question about the oil warning light on the dash; at what level does it come on?

I was filling the oil the other day and I accidently drove the car with low oil before I realised it, i.e.: the oil was slightly less than half way between the high and low marks on the stick.

But there was no warning light on the dash. How low does the level have to get before the light would come on? Is the warning light a reliable indicator of too low oil pressure?

I could not find a direct answer from the Mitsubishi Magna workshop manual.

Referencing a Pajero forum, and from a thread entitled "Oil Pressure", the consensus is that the oil pressure warning activates at 5psi:

And yeah oil light is for low pressure, 5psi I think.

https://www2.pajeroclub.com.au/forum...3&postcount=10




, which is somewhat less than the specified idle pressure of 11.6 psi:

Haynes manual 1997-2005
V6 petrol engines 3, 3.5 and 3.8 litres oil pressure 80kPa@idle

https://www2.pajeroclub.com.au/forum...01&postcount=4

If your oil pressure light activates for any length of time, and the oil pressure switch is indeed operating correctly, it is safe to assume that damage has been done.

[leadfoot6]

Its a long story, but briefly: I started the oil change without realising I didn't have enough oil on hand to finish. I was going to buy some oil the next day to finish but then there was a family emergency when my mum went into hospital for a week and I just forgot all about it while that was going on.
Later I drove the car three times (about 200 k's) before remembering.

What I find surprising is that the oil/engine light never came on. Never saw it flickering either.
When is it supposed to come on?

Is there any risk of damage while it was low like that? How would it behave if there was any damage?

As stated in post # 2, once again, if conditions are accurately represented by you, then there is no risk of damage, unless you subjected the engine to the (over)stresses that I also referred to in that post.

I don't believe that you would have done so.

Accordingly, sleep easy.

[KWAWD]

Thanks Leadfoot! I am a bit of a worrier so the more I think about this the more I'm wondering about it. It seems the oil pressure warning light is pretty useless if it only comes on after the pressure has dropped dangerously low! but that explains why I never saw it come on. Thats useless really.

As for driving the car hard; I don’t do that but I do remember on one of the trips the tippy was in manual mode and I forgot and when I went to drive from a stop it revved very high before I realised and put it back to auto.
That happens after I've driven a while on a freeway as I've found its better to have it in tippy mode, otherwise sometimes it downshifts too low for the 380 motor at anything over 90kmh. By keeping it in tippy I can manually switch between 4th and 5th as needed, which is all it needs at those speeds. For some reason I usually forget to put it back again after exiting the fwy and coming to a stop!

Well I went back to check my photos and I see the oil level was closer to 3/4 full than half so not as bad as I thought, but I am wondering how you would be able to tell if there was any damage done? Would there be anything to look for? Fuel economy? Noises? Seems ok, but I havent driven it more than a couple of k's since then. i can take it out later today or tomorrow for a test drive.

Mum is ok, she had kidney failure and had to have stents replaced. Somehow all the drama completely pushed the oil change out of my mind at the time. I had to drive over to mums a few times that week for things, which is miles away and then the hospital. I think the take away from this is to never start the oil change without everything being on hand first, in case you're interrupted.

[KWAWD]

Today I went for a drive down the freeway so
ran a simple test. Reset the fuel trip meter and drove 12 k’s. The fwy was mostly flatish.
I reset it once I reach 100 k’s an hour and turn on the cruise control, drove the 12 k’s and the reading was 8.4 l/100km which is typical for this car. Its always used a bit more than the KH on the same test.
I’m happy because it hasn’t even been serviced recently so this is a good result.
Didn't notice anything else with the radio off, sounded normal.

What this has shown me I think, is that its not super critical that the oil level sits smack dab on the max mark.
Here I was driving with it for a few trips on half way with no troubles.
I have been so careful to get it smack on the mark at each oil change but I think i’ll stress less about it now.
For example I notice its slightly over the max mark now (about 5 mm) but I’m not going to worry. In the past I would have carefully siphoned that off.

[WytWun]

otherwise sometimes it downshifts too low for the 380 motor at anything over 90kmh. By keeping it in tippy I can manually switch between 4th and 5th as needed, which is all it needs at those speeds.

If you'd fixed the shift maps as I've previously advised you, you'd have long forgotten this issue...