Steve Weiner-Rennsport Systems

Hi,

After responding to a thread in the 964 Forum, I thought this was a subject that might be useful for discussion here as well.

I've seen this happen far more times than I care to remember (thousands) and its painful to see, especially when it results in expensive (preventable) engine repairs.

The one common denominator in all these occurrences is an unfailing trust in the oil level gauge. Since this instrument takes some skill and experience to correctly interpret the readings, misinterpretations leads to these issues.

The bottom line here is that the "Dipstick is the Gospel". With a hot, idling engine, that flat piece of wire is dead-nuts accurate, albeit hard to read when the oil is clean, and really should always be THE primary way to determine oil level.

Lastly, dry-sump engines are VERY VERY different from wet-sump ones and oil levels should never, ever be maintained at the top of the dipstick range. Keep excess oil out of the intake system by maintaining oil levels halfway or slightly below and you will not have smoking issues, ruined & contaminated cats, extended longevity of oxysensors, spark plugs, and cleaner pistons & valves.

When I retire, I may very well write a book about all these kinds of things to help prevent air-cooled Porsche owners from such grief.

Cemoto

Steve,

Thank you for taking the time to write this.

It always seems the newbies have problems and tend to overfill.

It might be a good time to remind all about the collapsing internal funnel and it's degradation as well.

I'll be first in line to buy the book!

Best Regards,

Al

.

Steve Weiner-Rennsport Systems

Hi Al,

Careful what you promise, I may hold you to that!!

AOW162435

Steve,
Well said - thank you. The oil level topic seems a perpetual source of confusion.



Andreas

JB 911

Great post.

Also many have reported significantly less oil consumption when adopting the half or under technique. Furthermore, when oil consumption is a barometer for general engine health, this makes me sigh to think that some rebuilds may have been avoided with this simple advice.

https://rennlist.com/forums/993-foru...-your-oil.html

Seamless

When it comes to the car sitting on a level surface, how level is level? My garage floor has a slope for drainage and I have been slightly lifting the rear of the car to compensate when filling/reading the oil level. I use a bubble level on the door sill.

Matt Lane

I avoid the brain damage and do the occasional check at a tidy gas station on their slab which is invariably nice and flat.

M

OverBoosted28

What a coincidence. I took the car out (after a few weeks) for a quick spin. When I got home I checked the oil. Was barely showing on tip of dip stick. Put a quart in and brought it up to just over a 3rd up from bottom of twist. It's sorta hot here and I was in a hurry to get out of heat. Took car for a spin to cool it down before putting it away. Lots of smoke when I sped up :-(. Pulled over (again in the heat) and found trail of oil. Now I wanna cry, hate having a mess and instantly think the worst. Oil fill cap was cockeyed when I put it on. Pressure blew oil out onto passenger side, ran down all over exhaust. Wiped up as much as possible. Now I get to pull intercooler and spray "CRC electronic cleaner" all over to rinse oil off. So make sure, after all your effort to not overfill, that you put cap on correctly. Aloha

1st State 993

Steve,
Thanks for sharing your wisdom. My gauge is nearly useless. The dip stick level needs to be about 2/3 of the way up to get the gauge out of the red! This had always been my target - now I know better! Any way to make the gauge mire accurate?

Steve Weiner-Rennsport Systems

My pleasure; this subject has been a passionate one for me since 1976 as I've seen SOOOOO many people struggle with oil levels (and the consequences). Most folks simply do not understand how dry-sump oiling works and how to correctly maintain the systems, hence all the difficulties.

My hope is to offer something constructive that prevents these problems from recurring.

Regarding the oil level gauge,.......its been a problem since 1965 so this is nothing new at all. I've simply counseled my clients for almost 40 years on how to get their engines completely up to normal operating temperature (185 deg F), use the dipstick and understand when its accurate (hot, idling on level ground).

nine9six

Duplicate post...

nine9six

Based upon this post, I cant help but wonder if over filling of the oil is not a significant contributing factor to the SAI port clogging. Add to this, a faulty or corroded check valve, and the probability increases even further. Now, add in the stated root cause of worn valve guides, and I see a system with multiple points of failure...

One man in the business, seeing thousands of the same issue; why the statistical probability alone, must be staggering when considering contributing factors to the SAI issue.

EDIT:
If I were a betting man, which I am not; I'd even venture to say that early SAI clogging is PRIMARILY due to engine oil overfilling, and not worn valve guides. Not saying worn or oversized valve guides does not further promote the issue, but if the numbers Steve is quoting is correct, it would be very difficult to ignore the data!

tougu

Thank you Steve! Fantastic timing for me, I wonder if you wouldn't mind chipping in with an opinion:

I've been trying to track down a misfire CEL code on my 96. I noticed recently that when I topped up oil (to about 3/4 up the gauge) the code (P03XX) came back. Care to make a wild guess as to whether the oil level is perhaps too high and has gotten into the intake and fouled the plugs, causing the misfire?

I feel like most of the other potential causes have been analyzed - belt, plugs, wires, fuel delivery, tuning, grounds, and so forth. I know misfire codes (esp on a 96) can be tough, but do you think this could be it?

Cheers!

OverBoosted28

Even if you meant 3/4's up on the dip stick, that'd be too much. Forget you even have the oil level gauge until it's properly calibrated!
3/4 on the oil level gauge is (on average) way too much oil

PiB993

Any possible connection between overfill and smoke out the left exhaust but not the right?