Oil Level Question

gt_diesel · 08-13-2006, 06:18 PM

This may be a stupid question, but here it is.... What are the adverse effects of having the oil level a little high in the 930's? If the oil level is at the midway mark at an idle, The gague seems to drop down into the red when you get on the gas... If it is near the top it seems to drop down to about half...

After the oil was changed in my car, the oil level at an idle is a little above the full mark, but when getting on the gas, it will drop to about 3/4 on the gague.... Is that acceptable, or should some be drained out?

AFJuvat · 08-13-2006, 07:43 PM

It is a little high. As long as you aren't fogging for mosquitos, I wouldn't worry too much. The excess will burn off soon enough anyways.

AFJ

Eagledriver · 08-13-2006, 08:11 PM

If the oil isn't overflowing into the airbox then you don't have to drain it out. The oil level when you get on the gas is not important. The tank still has several quarts in it when the guage is in the red.

As has been said in many posts to this forum the only accurate check of oil level is at idle, level ground, engine fully warmed up.

-Andy

Jim Sims · 08-13-2006, 08:17 PM

Use the oil tank dipstick (in the filler neck), with the engine at hot operating temperature (~180F or more), idling and level to check oil level. Most keep level midway between dipstick marks. The tank level float gage will vary as you described depending on engine speed, car acceleration, etc. High oil levels can make a mess in the air box (look under your filter element) and on the top and/or bottom of the engine if it drains out of the airbox.

lindemans · 08-15-2006, 11:13 AM

To put you more at ease:
The level reading (both on dashboard as well as the dipstick) is totally meaningless at rpm's above idle.

At warm idle the equilibrium regarding oil in tank / oil in machine is the only reliable situation to measure whether the right amount of oil is in it.

I keep it half an inch under the max. reading of the dipstick.
This will keep the meter all the way up at warm idle (while driving the meter does indeed go all the way down).

hcoles · 08-16-2006, 06:57 AM

don't know about 930's but for 3.2 NA cars it is recommended to run in the middle of the marks or even a bit lower...of course this is checked with engine hot...best to be a bit above the first mark and at idle for maybe 1 minute...as lindemans and others have said. for 3.2 cars it is common for oil to foam up sometimes and go through the intake system, I don't think this is good... I don't see any harm for you to take 1/2 quart at a time out until you get to the right level.. then sleep easier

Carrera3.5L · Carrera3.5L's Garage

Quote:

Originally posted by hcoles
don't know about 930's but for 3.2 NA cars it is recommended to run in the middle of the marks or even a bit lower...of course this is checked with engine hot...best to be a bit above the first mark and at idle for maybe 1 minute...as lindemans and others have said. for 3.2 cars it is common for oil to foam up sometimes and go through the intake system, I don't think this is good... I don't see any harm for you to take 1/2 quart at a time out until you get to the right level.. then sleep easier

I'm curious to know what professional recommends this course of action or if this is simply internet lore that has become fact...

IMO, this practice is a bandaid for a different problem. I don't know of one high level shop that purposely fills a customer's car with oil to only the middle of the dipstick during an oil service and we certainly didn't perform this practice at Andial, regardless of engine size or whether it was turbocharged or normally aspirated. Can one of the professionals here (Steve Weiner, John Walker, Henry Schmidt, etc) confirm that this is accepted practice?

I have my personal car's oil level just a tad under the top mark on the dipstick when at idle, on level ground, and at operating temperature and I have NEVER had a problem with oil blowing through the intake system as described above. I'm also fortunate that the motor doesn't use any oil so I never have to refill before the 3,000 mile drain interval I use.

Ralph

hcoles · 08-17-2006, 05:25 AM

I don't have a list of professional references one company that is near me JW that I visit fairly often describes that the 3.2's often have an issue at high (6000) rpm where oil goes across and down the intake system. After hearing from so many places to run a qt. low..that's why I made the comment. If this is all internet lore and wife's tails... I guess it could be. On the other hand other than your post I have never heard or read that one should keep the oil level up to the top mark. Very likely just putting down the road...there would be no issue, AX and track could be another issue. When I took the top of the intake system off my car the other day...I saw some evidence of oil but that was in the form of a black layer of soot or not sure what to call it. If Henry or John Walker say to always fill to the top for AX and track for reasons...then I'll reconsider. btw - I daily drive my 89 3.2 with ax and track days, I wish I had the power of your car.

ischmitz · ischmitz's Garage

In my experience the oil get aireated and that is what mostly contributes to the volume expansion in the oil tank. The more oil you have in the tank to begin with the less room you leave for this expansion to not overfill it. There is alway more than enough oil in the tank to supply the gravity-fed primary oil pump.

I do not see any reason to fill up to the top of the dipstick at warm idle unless the owner/driver is someone who likely will not care and check the oil level during the service interval. In that case you buy her/him a little bit of safety margin that the engine won't run dry due to oil consumption. Two additional quarts could mean another 3000 miles before trouble hits hard

at normal oil consumption levels.

Other than that I'am curious if someone has ever recorded an oil consumption/1000 mile vs. fill level chart. I bet at some point closer to the Full mark consumption/1000 miles goes up quite a bit.

Ingo

Carrera3.5L · Carrera3.5L's Garage

Quote:

Originally posted by hcoles
I don't have a list of professional references one company that is near me JW that I visit fairly often describes that the 3.2's often have an issue at high (6000) rpm where oil goes across and down the intake system. After hearing from so many places to run a qt. low..that's why I made the comment. If this is all internet lore and wife's tails... I guess it could be. On the other hand other than your post I have never heard or read that one should keep the oil level up to the top mark. Very likely just putting down the road...there would be no issue, AX and track could be another issue. When I took the top of the intake system off my car the other day...I saw some evidence of oil but that was in the form of a black layer of soot or not sure what to call it. If Henry or John Walker say to always fill to the top for AX and track for reasons...then I'll reconsider. btw - I daily drive my 89 3.2 with ax and track days, I wish I had the power of your car.

There's nothing wrong with doing something that works for you, if you want to fill the oil up half-full on the dipstick that's fine but I personally don't believe that this is the proper method and is simply masking a problem. I speculate that I would have been fired from Andial if I tried to explain to Dieter or Arnold this rationale and did this with customers cars rather than trying to rectify the problem. Perhaps because we would be losing dollar sales of a couple of quarts of oil for every car?

As for wanting the same power as me, consider that you may be competitive in a stock type class you are racing in now but probably wouldn't be in a higher class that you would undoubtedly be placed in with extensive engine modifications. My motor is very mellow, I left alot of power on the table with the constraints I had to work with. One can do much better for a hot-rod street or race engine...

Ralph

Eagledriver · 08-17-2006, 09:22 PM

While the recommendation for running the oil at midrange is fine for street driving, it's a very bad idea for track driving. We find that on all 911's with stock oil tanks you must run at the top to prevent oil starvation in extended corners and heavy braking areas. This is also why many racers use modified tanks with more capacity and baffles.

-Andy

hcoles · 08-19-2006, 06:02 AM

ok, good input.. my car is basically stock motor and suspension and I'm doing DE days or track days.... I certainly don't want to starve the motor.. I guess this would happen in turn 2 at ThunderHill if anywhere...I think I'll start running the level 2/3 or so up and see what happens. thanks

lindemans · 08-21-2006, 02:26 PM

Quote:

Originally posted by ischmitz

Other than that I'am curious if someone has ever recorded an oil consumption/1000 mile vs. fill level chart. I bet at some point closer to the Full mark consumption/1000 miles goes up quite a bit.

Ingo

That's an interesting thought; I have meticulously recorded oil comsumption over some 5.000 mls with 1/2" below max; which gives me a quart to the 1.000 mls. I'll continue monitoring with lower level in the tank.