Gbos1

Okay so how do you disseminate from “Idol” time to actual miles driven? For instance… I have 5 months of Winter where I am and idol my car up to temp every 2 weeks as instructed by Porsche Classic … sometimes it takes 1/2 hour to get up to temp at idol?

frederik

Off-topic here, but don't do this! Let the car sit on a battery tender, don't touch it. Start it in spring. Idling to warm up takes a long while, and all this time the car is running on a rich mixture. The fuel seeps through the cylinders and dilutes the oil. Then you don't drive it so it doesn't get really hot, so the fuel doesn't have a chance to evaporate. This leads to excessive wear on the cylinders.

In addition, the warming/cooling cycle causes condensation in the engine, which dilutes the oil with water. Normally you burn that off when the oil gets hot, but it doesn't, so...

Ideally each time you start the car, you want to go on at least half an hour of driving.

Das14444

you dont. it’s all factored in. typically you will see about 30-35 mph as the average speed (unless its a track car and was trailered to the track or something)

a car with 35,000 miles would have about 1,000 operating hours = avg speed of 35 mph

a car with 40,000 miles with an average speed of 30mph would show 1300 operating hours

this could vary if your car is running idol for hours

the issue when the operating hours dont add up to the miles on the odometer: if a car shows only 9k miles but has 2000 operating hours (average speed of 4mph) thats not right…or a car shows 85k miles and shows just 500 operating hours (average speed of 170) thats also not right

in the first example the odometer stopped or was disconnected, in the second example the DME was probably reset or replaced at some point

Gbos1

Frankly, this is a load of B.S.! Moral of the story is unless it’s an outlier you can’t peg accurately miles to hours.

Das14444

what I wrote is certainly not BS…just basic DME diagnostic tools…but bury your head in the sand

notfastenough

Why the hours are not a critical measurement. Load of B.S. might be a bit strong. lol... Hours can certainly help with overall evaluation.

Oh... and you definitely shouldn't idle your car that long. Even Caterpillar states this is a bad idea, contrary to every truck driver in the world doing differently.

autobonrun

I know what you’re saying, it’s another piece of data.

The problem I see is having data misinterpreted or misused by the untrained or by those that get their training through internet comments. In a world where everything is computerized, more and more reports are available and I’m concerned what is next.

In over 40 years of engineering, I can tell you I had access to hundreds of reports every project I completed, but I only provided some of those reports to the general population. It was not an attempt to hide anything, but I provided all the information needed to make decisions and stay informed. Some of it was to be used for maintenance diagnosis and I had no intent in spending 8 hours explaining why the data wasn’t applicable in particular situations. All data is not information. But there are those that want it if they know it’s available. So in this case to get accurate mileage, you need more than a estimate of mph. So what accuracy is needed to satisfy perfectionists?

jfischet

nothing satisfies perfectionists, which incidentally is the problem with the world right now.

Braun

Thank you for sharing your experience and observations! I conducted a brief internet query for “Porsche 993 odometer failure” and I could use a reality check from knowledgeable participants on this thread.

It appears the premature 993 odometer gear failures started to surface about 10 years ago. I get a sense the typical lifespan for original 993 odometer gears is about 20 years + or - 5 years (15-25 yr), but they can ALL be expected to fail in this time, due to age not miles. Porsche USA never issued a recall for factory authorized correction, and Porsche Classic offers neither odometer replacement parts nor a standardized correction protocol. Likewise, PCA has not been active toward a broad resolution. 993 owners are currently on our own to repair premature odometer failure without meaningful Porsche USA and/or PCA support.

993 odometer gear replacement can be done by [perfectionist] owners but it’s a delicate job and experts advise to let a qualified shop and/or odometer repair specialist (North Hollywood, Odometer Gears, etc?) do it.

Am I close? Please feel free to offer [civil and respectful] corrections!

audiporsche71

Useful information and sounds about right to me (but I am a new owner). Speaking of which, the trip 1/10 digits on my 96 C4 move by in a stuttering fashion, not smooth. Is this an indication that a repair is in my future? Adam

ShdwFx

My odometer gear failed in 2009 but it was already a well known issue for several years before then, so I would say this has been around for closer to 15-20 years.

autobonrun

It didn’t start with the 993. The odometer on my 79 SC failed in June of 1998; so it lasted 19 years. This is in line with your timeframe. I had it repaired by North Hollywood, told them to add 150 miles, and returned it to service with no photos or fanfare.

Hmm, I wonder if the 964 model sees similar odometer failures?

Gbos1

911s, 924s, 944s, 928s …. It’s across the board issue……………. . . . . . . .

mdude

Saying odos are ALL expected to fail... My goodness, the mis-info perpetrated here...
It can fail, but it's not a must.
How many folks at one point believe it's just a matter of time before 993s develop SAI issues?

Luft Cool

Definitely not a must.

Our family has an original owner 86 944. It is still on its original (and working) odo. FWIW, we never press reset while the car is in motion.