weird oil reading problem

[CyFi6]

So i have this weird problem with my 7mge, it has 83k orig miles on it and when i want to check the oil, i need to make sure the car has been run all the way warmed up and everything first before i shut it off to check the level. If i decide i want to move the car before checking and jsut run the car a few mins and then check it, even letting it settle for a few minuets, it will show a low oil level. it will be about 1/2 to 3/4 quart low. If i drive the car and get it hot and everything and then check the oil itl be all the way full. Whats up with that?

 

[plaaya69]

Sounds weird. Are you sure you are checking the oil on flat level ground?

 

[CyFi6]

yes this is if i check on the same level spot

 

[IJ.]

It should be checked cold before the car has started to get an accurate reading.

 

[Figit090]

yeah...

i would think cold, more viscous oil (not warmed up) will not completely fall back into the oil pan, where hot oil is going to be less viscous and drain quickly back into the pan.

to test that theory you could check your oil, make a note. then run it for a bit but without warming it up, park it, wait like you did, take a reading. then wait an hour, check it again....my guess is it will be back up there.

 

[Tire Shredder]

yeah...

i would think cold, more viscous oil (not warmed up) will not completely fall back into the oil pan, where hot oil is going to be less viscous and drain quickly back into the pan.

to test that theory you could check your oil, make a note. then run it for a bit but without warming it up, park it, wait like you did, take a reading. then wait an hour, check it again....my guess is it will be back up there.

oil level has nothing to do with viscosity, and everything to do with where the oil is sitting.

like IJ said:

- unstarted (so it's all in the pan)
- level ground

 

[Figit090]

oil level has nothing to do with viscosity, and everything to do with where the oil is sitting.

like IJ said:

- unstarted (so it's all in the pan)
- level ground

maybe i used the wrong terms;

what i mean is, if the oil is thick and doesn't run back from the top of the engine to the oil pan, his reading will be 'low'.

if the oil is warm and not as thick, it could run back to the oil pan faster, filling the pan up to the 'higher' reading.

make sense? i'm not to familliar with how fast oil flows down a surface when hot as compared to cold...
and i know you need those two things to check the oil - i was just trying to brainstorm why the engine temp could effect it.

he did say he checked it on the same level spot and in both instances he started the engine, the only variable is temperature.

 

[IJ.]

I'm guessing he's just pulling the stick and looking at it after its ran and splashed Oil everywhere instead of wiping it and redipping.

 

[CyFi6]

No, i am reading it properly. Im not that stupid
I just never experience this with other cars so i was wondering why it was doing it, it seems that figit would be right in saying thicker oil wont drip or flow as well when cold, i guess that might have something to do with it if the 7m has small oil galleries.

 

[IJ.]

The lower tube may be missing so when you put the stick back in after it's been running the Oil that's dripping down the inside of the crankcase drips onto the stick higher up as you pull it back out to read it.

There is NO way that you can be showing more Oil after it's been running if anything it should read less as there's a Qt hanging around in the galleries, pump and head.

 

[AJ'S 88NA]

Change your oil and filter put the right amount in then start it let it run alittle to get oil in the filter. Then let it set until cold and check it. make note were it is and that should be your correct level.

 

[jdub]

I would run the oil level a quart high

 

[CyFi6]

Change your oil and filter put the right amount in then start it let it run alittle to get oil in the filter. Then let it set until cold and check it. make note were it is and that should be your correct level.

if i do that and warm it up and check it, itl probly be overfull

 

[jdub]

And the problem with running a quart high would be?

 

[Supracentral]

And the problem with running a quart high would be?

Better not be any, we run all of our Supra's that way.... :icon_razz

 

[CyFi6]

running with too much oil IS a problem. it gets high enough that the crank can dip into the oil and whip it up and foaming it up = no oil pressure

 

[Supracentral]

Ahem... I think we know that...

You can safely run more than one quart over a Supra (7M or 2J) and get nowhere near the crank...

 

[jdub]

running with too much oil IS a problem. it gets high enough that the crank can dip into the oil and whip it up and foaming it up = no oil pressure

Got any idea of how many quarts over full it would take before that would happen? Of course you don't, or you would not have made that statement. Time for a little research my man.

 

[CyFi6]

reasearch on how to incorrectly fill the oil pan? Please dont ask whats wrong with overfilling if youre gonna be like this after i state it, i cant detect sarcasm in text.

 

[IJ.]

When I was a kid just starting to work on cars at a neighbours place the father had a sign on the wall that's stuck with me all these years.

"Oh Lord help me keep my big mouth shut till I know what I'm talking about"

In this case it applies.

You need to pull a 7M pan and actually measure the levels before spouting crap about the crank touching the Oil and aerating it.