ByByBMW

Had my Boxsters oil changed late December and have since put over 400 miles on. Today, started the car, from a cold condition, and immediately got the max oil level alert. Up to now, the level has been consistent at all segments lit except the last segment, I.E. full but not overfilled.

Any ideas??? Dealer visit?

Marine Blue

Bad sensor?

Spokayman

Have you been driving a lot of short trips or have had extensive idling lately? Short trips and idling tends to cause a buildup of water in the oil (condensation) and this can actually cause the oil level to go up. If this is the case, take the car on an extended run or two at higher speeds to get the oil hot which will burn off the condensation.
If this is not the case, then perhaps a faulty sensor as suggested above.

Macster

What Spokayman said.

The only thing I can think of is the car needs to be on level ground.

BTW, if you check the oil level cold and it is at the max line the oil is likely to be above that when the engine and oil is up to temperature.

In cold weather my Boxster's oil level gains a couple of bars/segments once the engine is hot and I shut off the engine and then check the oil again hot, after the engine has sat long enough that when I get back in the car and turn on the key the oil level reading count down is just 5 seconds.

ByByBMW

Interesting because in my car, it is almost exactly the opposite. My oil level usually never changes from cold to hot. When I start from cold, the level is one segment from the top, up to full temp. and it is STILL one segment from the top.
I reset the oil level system and went for a drive, the whole time, the system showed level at one segment down. It wasn't until I shutdown and waited the one minute that I got the max level exceeded warning.

perretar

About 10 min. of idling on my Cayman gets the oil up to normal temp, why would that cause moisture build up ?

Marine Blue

Getting up to operating temperature isn't usually enough to burn the moisture out of the oil and exhaust. You often hear from people posting about a tan sludge on their oil cap, this usually occurs in cars that are driven short distances and never really get to the really high operating temperatures. The moisture builds up and condenses on the cap (coolest spot).

Before I learned this 15 years ago I used to start my car up during the winter. My car now stays off during the winter and I only fire her up when I'm ready to go for a drive.

swmic

Coolant temp and oil temp art two different things. Although your temp gauge may say the car is up to nominal operating temp, your oil takes much longer to warm up completely and get rid of the moisture.

Macster

This is contrary to what I have observed. A cold engine and its oil will have a lower oil level than the same engine parked in the same spot with the engine and oil fully up to operating temperature.

Unless there is some normalization of the level going on based on temperature the reading behavior you report suggests an oil level sensor problem.

You should consult with an experienced/trained tech about this though before even thinking about any wrenching.

Macster

To add what others have said no way the oil is fully up to temperature after just 10 minutes of idling.

What it takes is driving the car some time until the coolant temp gage needle has reached the point where it generally is when the engine is fully warmed up and then driving the car some more time -- another 10 or 15 minutes to be sure.

This will have the oil, all the oil, up to its operating temperature.

Even this is not sufficient though as depending upon climatic conditions the engine may be running rather cool. I have observed coolant temperature variations from around 180F in real cold weather to 226F in real hot weather.

Obviously, 180F is not nearly the boiling point of water at sea level. However, the engine crankcase does run under low pressure some of the time and this lowers the boiling point of water in the oil.

In short the engine needs to be run a good amount of time to get the oil fully up to temperature and kept there long enough that as much water in the oil will be boiled away as is possible.

Spokayman

Also remember that engines run rich at first start, and run more rich when the weather is cold. This introduces unburned fuel into the oil as well. The more cold starts and short trips the more often this occurs.
I don't know if the amount of unburned fuel has much of an effect on the oil level, but it dilutes the oil and it generally makes the oil less able to protect the engine.
For these reasons (cold temps, rich running, cold oil and coolant temps) many vehicles will adjust the service intervals of their engine to account for the less than ideal running conditions. As an example our MDX will allow around 8,000 miles in warmer weather, and barely 4,500 in the winter. I always change at less than these intervals anyhow.

Machog

The cheap, frivolous answer would be; "having only done 400 miles since you got it-is the obvious problem".

Take it out and and put 400 miles on in a day!

On a less frivolous note, put some serious miles on it in a day and then come back and check it. Even after mine (11 Cayman) is warmed up after 15 min or so, I can loose an oil bar after a long 'enthusiastic' run. Not scientific or based on anything sensible, just and observation.

Machog

medtech

Go get it checked out. Can't remember when or where, but I've had more than one indy tell me that having too much oil can be a bad thing.

ByByBMW

I've decided it's ambient temperature related. Over the weekend, Tucson set records for high temperatures. Today, the temps started out about 10-12 degrees cooler and I don't have the max level exceeded warning. But checking a couple of things and looking at the evidence tells me my car was filled to within an RCH of the max level sensor and I need to drain about a half quart of oil, which I will do when my replacement filters and drain plug get here AND i can get a local indie to rent me the time on a lift so I can get-er-done.

From now on, when I get the oil changed, I am going to have only 7.5 QTS added and that should be just right and of course I can always add a touch more as needed.

ByByBMW

Just noticed your definitions of understeer, etc. I like them do you mind if I borrow them?