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Spark plugs at 35k

 
Old 01-26-2017, 09:34 PM
  #16  
mtony
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Originally Posted by CSK 911 C4S View Post
Speaking of plugs.

I love how they sell 2 plugs. Both the same model number but one probably comes in a Porsche box.

$7 vs $20 each.

http://www.pelicanparts.com/catalog/..._pg1.htm#item0
The cool box adds hundreds of dollars in resale value!


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Old 06-12-2019, 12:36 AM
  #17  
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The maintenance manual in the 991.1 C4S states to change the spark plugs every four years. Iím coming up on that but my mechanic is telling me unnecessary. With all the talk of bore scoring and potential causes as being bad injectors or plugs should I go with Porscheís recommendation or is it excessive?

Car only has 15,000 miles on it, 2015 manual and drives fine. When should I replace sparkplugs, now or later? Donít care about resale but planning to keep this car for life.
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Old 06-12-2019, 02:23 AM
  #18  
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I would do it soon if it were my car. The other thing is plugs that stay in place many years supposedly can stick to the case and cause thread damage when finally removed. Overkill? Probably so but you want to keep the car and itís cheap peace of mind. Itís probably unnecessary for the plugs in terms of their performance / wear but a good idea to do, to not bugger your engine case just based on time and heat cycles. I did mine at 20k and 5 years if it makes you feel better!
yours are possibly 5y old now too assuming a 2015 got built in 14...
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Old 06-12-2019, 06:41 AM
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I am in same situation - I have a 2015 and just hit my 4 year anniversary so basically I am supposed to change them out this year. I may do them towards the end of the year or wait until next year but agree with @greg they should be done at or soon after the recommended time frame. Can't hurt and is cheap insurance.
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Old 06-12-2019, 09:37 AM
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I changed mine on my 2015 last weekend at 18,500 mi as part of the complete 4 year / 40k service. I also debated whether it was necessary but in the end asked myself when has it ever been a good idea to undermine / extend the service intervals recommended by a manufacture? In most cases many of these intervals should be shortened and not lengthened in my opinion ( especially oil).

In any case, the original plugs looked good but were a little tight coming out so I can see the logic on the 4 year 40k interval though I've never experienced nor heard of one completely seized in a head. Besides, changing the plugs gives you or your trusted technician a great opportunity to get up close and personal with your engine. I was able to determine all 6 cylinders are running properly and inspect the ignition coils as well and have zero regrets about changing them. I was also surprised at how dirty the engine air filters were as I do not live in a particularly dusty area in the Northeast.
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Old 06-12-2019, 07:45 PM
  #21  
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Originally Posted by Lucky991 View Post
The maintenance manual in the 991.1 C4S states to change the spark plugs every four years. Iím coming up on that but my mechanic is telling me unnecessary. With all the talk of bore scoring and potential causes as being bad injectors or plugs should I go with Porscheís recommendation or is it excessive?

Car only has 15,000 miles on it, 2015 manual and drives fine. When should I replace sparkplugs, now or later? Donít care about resale but planning to keep this car for life.
I was in the same situation as yours. Changed them at 4 year interval with 17000 miles. Thatís just me.
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Old 06-12-2019, 07:49 PM
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Originally Posted by limegreen View Post
I changed mine on my 2015 last weekend at 18,500 mi as part of the complete 4 year / 40k service. I also debated whether it was necessary but in the end asked myself when has it ever been a good idea to undermine / extend the service intervals recommended by a manufacture? In most cases many of these intervals should be shortened and not lengthened in my opinion ( especially oil).

In any case, the original plugs looked good but were a little tight coming out so I can see the logic on the 4 year 40k interval though I've never experienced nor heard of one completely seized in a head. Besides, changing the plugs gives you or your trusted technician a great opportunity to get up close and personal with your engine. I was able to determine all 6 cylinders are running properly and inspect the ignition coils as well and have zero regrets about changing them. I was also surprised at how dirty the engine air filters were as I do not live in a particularly dusty area in the Northeast.
Agree, Iíll change them at my next oil change. I just like to know there is actual wisdom behind a manufacturerís recommendation and not a cash grab. Never had a time interval on plugs on any of my other cars so its just new to me. Should I do the same on my N52 BMW? It hasnít had its plugs changed for 100,000 km or 6 years or so. Same with my 2006 S54, 53,000kms on a 13 year old car and plugs have never been changed. Whats unique about the 9A1 that requires this?
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Old 06-12-2019, 08:10 PM
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Originally Posted by Lucky991 View Post
Agree, I’ll change them at my next oil change. I just like to know there is actual wisdom behind a manufacturer’s recommendation and not a cash grab. Never had a time interval on plugs on any of my other cars so its just new to me. Should I do the same on my N52 BMW? It hasn’t had its plugs changed for 100,000 km or 6 years or so. Same with my 2006 S54, 53,000kms on a 13 year old car and plugs have never been changed. Whats unique about the 9A1 that requires this?

That's an excellent question as BMW ( along with most manufactures) does not specify a time interval but only a mileage interval on your N52 ( recommended @ 100k mi) or your S54 ( recommended every other inspection II @ roughly every 60k mi). I have extensive experience with both engines and have never seen an issue with either regarding the physical plug changes themselves though the intervals themselves can be a bit too long primarily in instances where the vehicle is used in a more city type or aggressive driving environment.

Regarding what makes Porsche different in respect to plug intervals.(This interval was also the same in the M96/97 series engines as well in the (996,997,986,987) I really only have one theory as to why the interval is much shorter and recommended every 4 years.

The fact the Porsche's are perceived by the engineers to be used more aggressively on both the road ( Autobahn) and track and also with the possibility of long sitting times ( when utilized as a secondary type vehicle) has them worried that the wear could be more excessive than a "normal" vehicle leading to possible issues with premature wear resulting in less than optimal engine / efficiency performance?

Last edited by limegreen; 06-13-2019 at 10:28 AM.
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