Temp Hashmarks and Measuring my Oil
 

Hi All,

I've read through a number of the threads about checking oil and I wanted to ask. What do the temperature hashmarks mean and when should I check my oil? Here's an example:

Typically, when my car gets all the way to normal driving temp (for me, at 75 - 78 degrees on a Miami morning, it seems to be about 1/8th of an inch over the first hashmark in the temp gauge), my oil gauge needle sits at about 2/3rds to 3/4ths full. This usually happens after about 40 minutes in traffic. The dipstick shows about the same.

Today it rained, and during normal driving my temp actually DROPPED to slightly under the first hash mark. The oil gauge all of a sudden was reading at about 1/4th to 1/2 oil level when sitting level and letting everything settle.

So the question is, when does my oil reading count? After driving 40 minutes in the rain, my car shows cooler than normal, and oil level is lower than normal, but is the car not "warm" at this point?

Should I just go by the highest measure I get? 3/4ths to 2/3rds?

Am I possibly overthinking the hell out of this? :p

That all sounds pretty normal to me. Mine's about the same. It fluctuates a fair amount with the temps. The trick is to make sure it's up to operating temp and the thermostat opens to feed the front oil cooler before checking. For mine that's when it just passes beyond the first hash mark. I was paranoid my first winter in Atlanta because it would be a struggle to get it hot enough to open the thermostat and I would think the oil level was low, when in fact it was fine.

I try to keep mine around the halfway mark on the dipstick with the front cooler open. Over filling can cause it own series of "messy" issues.

No, that's not a fair statement. :rolleyes:

To the original question... you car seems to be operating normally. A 911 will have different ultimate oil temperatures when fully warmed up, depending upon the ambient temperature and how it is being driven. The temperature may go up or down slightly, if conditions change. "Fully warmed up" means as warm as it is going to get in a given set of conditions. In the middle of the country, when it gets really cold, fully warmed up will be well short of the normal range, which is generally around the 90C hash mark.

The oil level gauge shows the level of the oil in the oil tank. This level will increase with increased temperature. When full warm, the oil will be at a level in the tank that is going to measure somewhere between the two hash marks on the oil level stick in the tank. The gauge reading should roughly correspond the the stick. All of my cars have had gauges that were well calibrated; some people ***** that theirs don't work. I don't know if these people actually have a problem they need to fix, or if they just don't quite get it.

I generally run my oil level near the top of the tank stick upper hash mark and add oil when it gets a quart low, if it uses that much between changes. I've never had a problem with overfilling, the oil volume increasing too much, etc. You'll notice that, if you run a fairly full tank, you'll see the gauge registering above zero when you run down the road at normal engine speeds. If you fill the tank to the lower mark on the stick (too low) or halfway between the marks, the gauge may show zero oil when running down the road. It's all normal.

The bottom line is to get used to what your car does.

JR

I actually like my oil level gauge.... I've checked it against the dipstick enough times that it's spot on accurate. I don't rely 100% on it but it works great. Does what it was made to do!

I've owned 8 911s over the past 30-40 years and none of them have sucked any oil into the intake when the oil level was at the upper mark on the stick. Of course, I'm smart enough to fill them when they are hot and not in the dead of winter. I don't recall a single oil level gauge that didn't work as it was supposed to, either.

My clocks have been as accurate as the watches I've worn, too. Not saying they are as accurate as a modern digital watch, but they have been close enough.

Maybe you need to fix some things on your car.

JR

Yes, you are probably overthinking this a bit.
Sounds like normal changes in volume due to temperature.
You car has about 12 quarts of oil, so a half quart plus or minus is trivial...unlike a car that only has 5 quarts

These will help

http://forums.pelicanparts.com/uploa...1445882680.jpg

http://forums.pelicanparts.com/uploa...1445882710.jpg

In hard cornering, or high revs brusque throttle lift, the car Will suck oil into the air filter if filled above halfway. There is no need to fill to the top hashmark.

All of these blanket statements about sucking oil into the airbox... You guys realize that Porsche routed the oil breather hose into the intake in many different ways, right? And, you also realize that at high revs, the oil level in the tank drops, right? And most people that have the problem of sucking the oil into the intake have overfilled their tanks by at least one or two quarts...

Give it a rest.

JR