Sorry for this pedestrian query (searched the topic and didn't see anything about it) but I check my oil level after every drive in my 987.2 and sometimes get the full reading and sometimes get the 1 block down reading. Why is this?

 

Sometimes you're not quite level when you start the reading.

Sometimes you have a lot of short trips and moisture adds to the oil level. Then you have an extended drive and the moisture burns off and the level drops again.

Sometimes you're level is 'between the lines' and you see the reading based on the resolution range of the sensor.

Anyway don't sweat it until you are 3-4 bars down, each bar is only 1/4 quart.

BD

 

Yeah, readings can vary by a little depending on how flat your car is (or not) at the time of measurement. Also, it usually reads 1 bar higher when the oil is hot vs. cold or lukewarm, at least IME (2 Boxsters).

No sweat.

 

The car is always on my level garage floor and engine is always up to temp at time of reading. The sensor won't give a reading until engine is up to temp and has been at rest for a certain number of seconds. Any way I am not really sweating it but I was curious as to way the level would be lower one day then higher then lower etc.

 

Up to temp is relative. While the system takes a reading if the engine hot enough this is not the same as the engine being the same temp all the time.

IIRC with my Turbo the oil temp has to be 70C to be hot enough. That's only 158F. But the oil temp can reach probably exceed 200F upon occasion so the oil level reading taken at 158F will be lower than the oil level reading taken at 200F all other things being equal.

Also, in my 02 Boxster there is a 'bug' in the oil level system. I have not been able to detail the exact circumstances but what I have observed is after cold start, some idle time, then a short drive -- just a few blocks and I turn off the engine for a few minutes while I run into the convenience store for something when I get back to the car and turn on the key the countdown timer shows just 5 seconds until a reading can happen.

Since I do not expect this -- knowing the usual time remaining should be minutes and lots of them -- I do not bother to actually let a reading happen but instead just automatically turn the key from off to on to start. I only catch a glimpse of the 5 second value.

But I have a few times paused to confirm this is real and at least once actually let the reading take place. Unfortunately I can't recall now what the reading was. Real low or where it should be? I do not remember.

 

I believe Macster is right.

Gen 2 will let you measure oil level when the water temp is up to par, not necessarily oil temp (though it will be closely related). I'm not saying that it's measuring cold oil level, but oil temp will always lag behind water temp. "Hot" oil temp will range from mid-100s to mid-200s (hot track).

Say you're driving home and the coolant temp reaches 210 or so degrees (though the gauge will show normal temp). The fan will kick in and try to lower the coolant temp (thermostat should already be open by this time). Coolant temp will start to decrease but oil temp will be much higher. In this kind of scenario, the oil level gauge may read 1 bar higher.

On the other hand, let's say you just drove during a cool morning on a highway and achieved good speeds home due to lack of traffic (very little stop and go). The higher speeds/wind velocity would've kept your water temp lower and the oil temp would be correspondingly lower than previous scenario. You get home, park it, and measure the lower temp oil. In this kind of scenario, you may get 1 bar lower.

In any case, my guess is that your oil level is very close to the threshold between the 2 levels and that's why small fluctuations will result in 1 bar higher or lower. Remember, 1 bar equates to less than 1/2 quart (slightly over 0.4 qt. IIRC..... EDIT: or was the whole gauge ~0.42 qt.?? Anyway, they vary by very little) so being close to the threshold and having hotter oil may put you over the line.

I'm sure this is way more than you wanted to think about , but I used to be curious about the same exact scenario and looked around a bit regarding this subject.

Cheers.

 

Thanks guys for the good info, I kind off thought it had to do with oil temp and being between the threshold of the 2 marks.