Schpee007

Hi All. I am one month into my first 911 and am trying to learn all I can about these fantastic cars. One thing that struck me during my buying research process was the maintenance intervals (engine life blood oil changes aside, I get that). For example, new plugs every four years seemed surprising to me given the build quality of 911s. Are the intervals meant to keep the car at "peak" performance, but aren't necessary for the car to run well and for a long time? Would appreciate the experience and insights of the rennlist community. Thanks!

997v2cabrio

Good point. You would think they would last 100K miles like other modern engines.

Cbst09

I had the same questions. Mine is an 09 and only has 17,000 miles and it's likely that I'll hit the time rather than the mileage for many of the changes. For spark plugs if the interval is 4 years or 60k and since it's already 4 years old I'm wondering if I really need to change the plugs or if I can wait till I see any drop in performance prior to changing them. Same question for the serpentine belt

PhilD

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fskof

I was told that the reason for the 4 year spark plug change is to prevent the plugs from seizing into the engine. Most 911's are not daily driven so it can take 10-20 years for them to reach 100,000 miles. The 911 is a car that you don't want to go cheap and skip its maintenance.


Remember: Its ALWAYS cheaper to MAINTAIN than to REPAIR!

Schpee007

Thanks, fskof. By seizing do you mean getting stuck in their sockets? I would hope four years isn't enough for that to happen. Average years to 100k for regular car is 6-8 years, I'd guess, so would hope 911 plugs could confidently go that long.

Thanks for the insight. Agree maintain way cheaper than repair.

997_Toronto

My approach is to read the recommended maintenance schedule suggested by the manufacture provided the driving conditions have remained within suggested limits. Most people don't drive their 911s in the winter resulting in a different type or wear & tear.

Read the recommended maintenance schedule, check the parts that are being identified as needing replacement, and if they look road-worthy, I will note the observation date and schedule another review at a later point in time. It's the same approach as oil changes...depending on where and how you drive (city / hwy / track), your oil change schedule will vary and cannot be purely dependent on milage.

If you go to your P-dealer, they will always recommend sticking to the maintenance schedule by the book due to warranty and other liability issues but if you get an honest Indy, they will save you money without jeopardizing your investment.

Chrono

The advent of 100k mile spark plugs had to do with 100k mile emissions warranty, on Honda, Toyota, many US cars too. Not sure about German cars.

On the Bugatti Veron, you have to change the wheels every 20k.

USMC_DS1

+1... Porsche does not recommend the use of anti-seize grease on the plugs. These modern plugs supposedly use some type of metal alloy which behaves much like anti-seize already. Plus the Porsche torque spec assumes that no anti-seize grease is used. Porsche even published a TB against the use of anti-seize grease. I'll likely change my plugs prior to the 4 yrs mark just to be on the safe side. I've had to deal with seized plugs on my son's 4Runner... never again! Plus it's only $65 for a set of plugs for a 997.1 C2S.http://www.pelicanparts.com/cgi-bin/...itemquant=%206

fskof

I have a friend that is a Toyota Service Technician and he told me he has snapped many spark plugs because the owners would wait till 100,000 miles. He hates to do them when a owner pulls in with a 8 year old car that has never had the original spark plugs removed.
A simple job as changing spark plugs becomes a major job trying to remove a spark plug that has snapped!

Macster

The build quality of the car or even the engine (within normal ranges of acceptable quality) has nothing to do with plug life.

Plug life is a factor of how fast the plug electrodes erode and the gap becomes too large and spark is affected. These engines operate at the border of incipient detonation. The knocks sensors with the DME keep detonation at bay but the plugs take a beating. I note Porsche specs plugs with an extended tip and multiple ground electrodes which helps extend plug tip and electrode life.

There is that, but there is plug life that is affected by the climate in which the plug, the car is used.

Driving in wet/damp or icy/salty areas splashes the coils and plugs with water. (Splashes everything under the car I might point out.)

The 911 with its rear mounted engine has the engine really positioned to get thoroughly doused with whatever the tires kick up. This is one reason why these cars come with a good application of cosmoline on their undercarriage hardware. It is also one reason why in the UK coil life appears to a measured in months and in the UK. And in why in areas of the USA which have salted roads exhaust hardware has a short half life.

Anyhow, this corrosive mixture of water/salt will over time work its way into the threads of the plugs and corrosion begins.

Obviously cars that have their engines located up front and higher do not get nearly the exposure to the elements.

Which reminds me: Every time I wash my Turbo the engine gets wet. While the engine has never misfired after a start from a washing it has misfired (twice) from being left out in the elements overnight. My point is these engines are somewhat exposed to the elements both from under the car and from above the car.

The number of miles change schedule covers those cars that see a lot of usage.

The number of years change schedule covers those cars that may not see a lot of usage but could still be used in harsh climatic conditions.

BTW, the plugs could go 100K miles. My info is in the USA for an engine to qualify for sale here it must run 100K miles with no other servicing other than oil/filter changes at the scheduled miles. Plugs, not even rubber timing belts can be changed.

CAA

The manual says 40,000 miles or 4 years, whichever comes first. I'm way below the miles but am having them changed out when I have an exhaust put on in a couple weeks since they'll already "be in there".

yashagrawal

My car was 4 years old when I purchased it at 8500 miles, the dealer changed the spark plugs as part of the CPO service at 4 years.

yashagrawal

BTW, what is the recommended interval for alignment of wheels in a C4S. Also, does it vary by model ?.

997_Toronto

Don't you get an alignment when you switch tires or am I misunderstanding your question?