kkim

Greg,

I guess the conventional wisdom is not to trust what the gauge is saying as "true". Yes, once you "calibrate" your gauge against your dipstick, I doubt if it will change. The caution was to not trust the gauge w/o knowing what the corresponding reading was on the stick.

In John's original question, he was using the gauge saying it was "full" and he was worried if it was overfilled. My recommendation was to read the dipstick to double check his gauge and rely on the dipstick reading as the "true" reading.

Terry Adams

I calibrated the gauge against the dipstick several times in the first 20K miles of ownership. Since then, I also see a gauge reading full every time the car comes back from an oil change. I am using about 1qt/2500 mi. I keep the oil topped up to about 2/3 on the gauge, and must confess to not having used the dipstick for years.

Monique

Terry & Greg,

Tsk, tsk, tsk! Gauges fail or give false indications. Had many do it to me.

Mechanical dipstick works absolutely. Gauges? Never sure.

rainmn

I agree, however this assumes you can actually read the dipstick. I find it very difficult to get an accurate read on that stupid spiral.

Rob 97 993c2

do you also add oil with the engine idling? I check it with the engine on, but do you shut off to add oil?

Father of 3

You can definitely add oil with the engine idling. The cool thing about this is you can see the oil guage needle go up as you add oil, although I tend to agree with Graham, the guage can be misleading. Mine pegs down to the bottom when the oil level is just below the midway point on the dipstick. Disconcerting but I usually take solace in having very good oil pressure (between 4-5 bars) at 3-4k rpms and measure with dipstick very frequently (still a paranoid newbie).

993inNC

Could it be that we are making too big 'a deal of this? I drove over 1000 miles home after picking up my car a couple of months ago. That level gauge NEVER moved off the red. Now having said that I, along the way added a quart or two...nothing. Which could only mean that the oil was lower than two quarts (if what I had read about the stick was true), the pressure gauge acts no differently now than it did then (and I have 2 bar@ idle, and goes up from there with rpms). Both gauges couldn't be wrong, and I am probably coming up on 2500+ miles without adding a drop nor a change in the level gauge from when I first did a complete oil change after purchase.

Moral to this, I was clearly way down on oil for the trip home. The pressure always remained and continues to remain high (and normal for whatever the rmp's) and with no apparent wear or damage to the engine. Could it be that with a dry sump system, under normal driving, as long as there is some oil in the tank and driving doesn't get abusive or spirited that its okay to not panic over a little discrepancy in how the dipstick is read? Remember there is some part of 10 to 12 quarts in there, should be plenty if you're operating in the normal temp range........no?

Monique

Another factor is the "oil cooler bypass valve". Until it opens with oil temp higher than 80C, the oil quantity gauge stays pegged at the bottom.

After the solenoid (assumption) actuated valve opens, the oil temp drops to about 65C, then resumes warming as the cold oil from the cooler mixes with the oil in the tank.

Another reason to use the DIPSTICK... only when fully warm.

993inNC

My gauge doesn't stay pegged at the bottom, it begins to slowly rise right from the start. As the oil warms is when it stablizes. When I did my oil change, I made sure the car had a slight "list" to the rear in the hopes all the oil would drain from the front.