Oil level gauge question: Why the red marks above "8"? and below "5"?

[H.G.P.]

I assume the red marks (high above 8 or 9 ish, and below 5 ish), are warning areas on the gauge. So my question is why wouldn't Porsche have the "red zone" say at 6.0, or even 7.0!!

[Grady Clay]

It is because there are two different situations being addressed by the same gauge. In the area above 8 you start getting close to burping some oil out of the sump tank and into the air cleaner assembly – making a big mess and possibly getting oil into the intake.

The other situation is below 5 where there may not be enough oil in the system and it will start picking up air and trying to lubricate the engine with that. This is particularly true at high revs and high G loads from spirited cornering and braking. Really bad things happen if you run too low.

The level gauge is just an indicator so you know to look at the dipstick. All measurements should be done with the dipstick, the engine at normal temperature, on level ground, and at normal idle.

Anyone who ever drives a 911 knows that the oil level reads low when the engine is cold or revved up. That is because there is much oil “in process” draining back to the sump pump in the bottom of the engine case.

Every time you drive your 911, be sure the level comes up to the acceptable range when warmed up. I like to keep mine right at the high mark, even a little above, when the engine is as hot as it ever gets.

Best,
Grady

[HarryD]

Hi Grady,

Another question on interpreting the OEL gauge. At normal operating temperatures (about 190 per my temp gauge), my OEL gauge bottoms out when the dipstick shows a level about 1/4 betweeen Full and Add. Is there any reason (other than getting the panel gauge to read) not to wait until it gets to add before I add a quart?

I should note that when it is truly hot (210 ish), it will read a bit above the lower red mark and the dipstick will show 1/3 to 1/2 way between add and full.

[KCPSG]

generally the OEL gauge in most peoples cars don't work quite accurately, you should always read your dipstick once your car is @ normal operating temp. and your oil level should be 1/2 way between the 2 marks (reading on level ground) as you accelerate your engine is taking oil from the tank and pushing it through the engine. so your gauge should read a lower level as you are accelerating.

I always end up adding a little oil when the OEL level gauge starts reading a little lower than half @ full operating temp, however the hotter the oil gets the higher your oil level gets so be sure not to overfill.

[Drdogface]

Perhaps a newbie question here but here goes. On a cold start should you wait until the OEL gauge shows half or so before you start driving? Mine will languish on at the bottom for some time before it 'wakes up' but my dip stick will read just fine when warm.

[H.G.P.]

Thanks Grady and KSP.

I knew about checking from the dip stick. But I'm starting to understand the gauge fluctuations now.

My gauge starts out as noted and then usually changes as per Grady's post.

Thank you!

[Paulporsche]

Matk,
Start the car, wait a few seconds until the engine runs smoothly, then go. Drive by keeping the revs under 4000 until you hit about 180F, then go for it.

[Drdogface]

Pau,
Thanks for addressing my question. Love to see a pic, BTW, of your Yellow coupe....

[rcaradimos]

My 3.2l will read 1 quart low on stick from between the lines, i'll add the quart and it will drink it in about 400 miles. if dip stick just reads at tip, oil consumpion is almost none in 400 miles. fully warm and running. I tend to keep it there but if i intend on doing some long hwy miles i will bring it up to between the top and add lines on the dip stick.
Some oil consumption i think is welcomed by the cylinders, 2 strokes need the xtra lube and some of the constent high revs on the 3.2 might enjoy the same in a slight but not fouling manner.
Just a thought.