[87gtconvert]

87 5.0 119k... Now that it has got cold out here in Cincy, the oil light is coming on when the car is cold from over night or when having sat for a bit in 40 degree weather. Oil level is fine. When you start it the light is on for a a min if not less. Once the car runs for that little bit if not just 10 seconds or so the light will flicker a tiny bit and go out. If you good it a little it may go out sooner. The same time the needle gauge stays up where it should be, moving as you goose it. The car does use oil, a quart a MONTH maybe. No burning, no leaking, bottom of motor/car is clean.
Could I be lucky and the sensor for the light is just bad in doing its job when cold or do I have an oil pressure issue when cold. The car never makes any chatter from the motor as if it were starving for oil.
I do plan to change out the oil sensors soon.

 

[seijirou]

87 5.0 119k... Now that it has got cold out here in Cincy, the oil light is coming on when the car is cold from over night or when having sat for a bit in 40 degree weather. Oil level is fine. When you start it the light is on for a a min if not less. Once the car runs for that little bit if not just 10 seconds or so the light will flicker a tiny bit and go out. If you good it a little it may go out sooner. The same time the needle gauge stays up where it should be, moving as you goose it. The car does use oil, a quart a MONTH maybe. No burning, no leaking, bottom of motor/car is clean.
Could I be lucky and the sensor for the light is just bad in doing its job when cold or do I have an oil pressure issue when cold. The car never makes any chatter from the motor as if it were starving for oil.
I do plan to change out the oil sensors soon.

I think that light is an oil level light. I don't think the foxes have an oil pressure light, just the gauge. It's been a while though I could be mistaken.

 

[liljoe07]

Has nothing to do with oil pressure. The light works by the sensor grounding out and providing the ground source for the bulb to turn on. Probably just the sensor in the pan.

 

[orl1mjf]

Going through a quart a month is quite a bit, it must be burning or leaking it somewhere. What weight oil are you running?

 

[87gtconvert]

So the needle gauge is PRESSURE and the LIGHT is low oil? Well right now it is full. But there have been times where I have topped it off and a few weeks later it is low over a half a quart again.

 

[seijirou]

So the needle gauge is PRESSURE and the LIGHT is low oil?

That's right.

 

[87gtconvert]

I looked at three car parts places today, two of them did not even list the low oil sensor and the other did but could not even order it. What the hell? This part is in TONS of cars, why isn't it avail in parts stores?????

 

[orl1mjf]

No parts places seem to stock them for whatever reason. I have found them here
Mustang Low Oil Sensor at LRS - Free Shipping!

 

[87gtconvert]

Yes I found that site. BIGGER ISSUE though. My 17 year old son has been "checking the oil" well I did today and it was off the stick. It took a GOOD 2.5 quarts to get it back to full.
This makes about 5.5 quarts put in it in the last 6-8 weeks. That is a TON. There are no leaks, no smoke out the ass end, nothing. Where is it going? Rings bad? I have been told it is read main seal? Would that leak onto the garage floor?

 

[orl1mjf]

I would think if it was leaking that much you would see it somewhere, floor, block, trans. etc. I'm sure some will disagree with me, but early 5.0's are known to use some oil, not 6 quarts in a week though. What weight oil are you running?

 

[everett2]

How many miles are you putting on it to burn that oil. Is your son out hot dogging it.
I suggest using a high mileage oil. Forget mobil 1. The threads I read at bob is the oil guy just about everyone who uses mobil experiences more oil consumption than other brands.
Quaker state defy is great stuff. Pennzoil high mileage is good too. Valvoline high mileage also aids as far as consumption.
Going slightly thicker may also help.
I use 0w-40 in every vehicle I own. I suggest using a 0w-40 or 5w-40 so that the oil pumps fast when cold started. 10w-40 flow slower at start up than a 5w or 0w.

 

[87gtconvert]

I am using 10w40 in it. The car is getting maybe 200-250 miles a week put on it. It is just getting used around town, to school and back, no HWY driving, stop and go 25-35 mph speed limits. He does hot rod a little but nothing bad.

How many miles are you putting on it to burn that oil. Is your son out hot dogging it.
I suggest using a high mileage oil. Forget mobil 1. The threads I read at bob is the oil guy just about everyone who uses mobil experiences more oil consumption than other brands.
Quaker state defy is great stuff. Pennzoil high mileage is good too. Valvoline high mileage also aids as far as consumption.
Going slightly thicker may also help.
I use 0w-40 in every vehicle I own. I suggest using a 0w-40 or 5w-40 so that the oil pumps fast when cold started. 10w-40 flow slower at start up than a 5w or 0w.

 

[87gtconvert]

I would think if it was leaking that much you would see it somewhere, floor, block, trans. etc. I'm sure some will disagree with me, but early 5.0's are known to use some oil, not 6 quarts in a week though. What weight oil are you running?

I will look closer but when we changed the oil last I did not notice anything that would have make me think UT OH. Couple drips on the ground time to time under it, thats all.

 

[P40E]

If i was 17 and i had a chance to drive a mustang i would be flooring it at every light . :evilgrin:

You need to start checking the oil yourself . If you are losing a quart of oil every 250 miles thats a bit excessive i would think . If its leaking you would see it somewhere . If its burning the cats. might be hiding the smoke . Hard driving would burn more oil .

 

[orl1mjf]

I agree with running a thicker oil, high mileage formula or a additive like Lucas, see if the consumption drops.

 

[87gtconvert]

I agree with running a thicker oil, high mileage formula or a additive like Lucas, see if the consumption drops.

Thanks guys I will try the tricks you state to do. Yea he is 17 but I am on him all the time to take it easy on the car, more the reason now.
Could this be a ring issue?

 

[Hack]

It doesn't take much oil burning to go through a quart in 250 miles. The engine is just getting worn. If you don't get a puff of smoke on startup the valve guides are probably ok but a little oil is getting burned (getting past the rings).

The dash light probably is going on when it's cold due to the oil level in the pan being slightly low plus the cold oil isn't draining back to the pan quickly enough. You want to let the car get a little warmer before you step on it too much. Higher RPMs will suck the oil out of the pan faster. From your description it sounds like the oil level sensor is working. It's telling you the oil level is getting low due to slow drain back. All your oil is getting pumped up into the valve covers at cold startup.

Probably 5W 30 would do better at cold startup as well. DO NOT go to thicker oil as it will drain back even more slowly during cold startup! You could run the oil pan dry and oil pressure will drop to zero (momentarily). That's not a good scenario.

 

[87gtconvert]

Well the oil light was comin gon because he ran it a good 2+ quarts low. It was not even on the dip stick. I THOUGHT he knew how to check oil but I guess not. gave him another lesson.
I have been saying to take it easy on the old car, they will be FRISKY on ya, specially when it gets cold. They don't like cold like some of us old folks, me anyways. As fast as it is burning how often should I change the FILTER? ha ha ha.

It doesn't take much oil burning to go through a quart in 250 miles. The engine is just getting worn. If you don't get a puff of smoke on startup the valve guides are probably ok but a little oil is getting burned (getting past the rings).

The dash light probably is going on when it's cold due to the oil level in the pan being slightly low plus the cold oil isn't draining back to the pan quickly enough. You want to let the car get a little warmer before you step on it too much. Higher RPMs will suck the oil out of the pan faster. From your description it sounds like the oil level sensor is working. It's telling you the oil level is getting low due to slow drain back. All your oil is getting pumped up into the valve covers at cold startup.

Probably 5W 30 would do better at cold startup as well. DO NOT go to thicker oil as it will drain back even more slowly during cold startup! You could run the oil pan dry and oil pressure will drop to zero (momentarily). That's not a good scenario.