When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've been doing research on bore scoring for over a year, but I have never owned a Porsche before. I have learned this much:
1. C2 with the 3.6 is less likely to score, but the C2S 3.8 is the most notorious offender.
2. Some people drive their cars blissfully ignorant, with scoring, and never have problems.
3. The problem, by the sheer numbers, is not as common as everyone is led to believe...but when it happens it's bad.
4. C2S cars from cold climates seem to be the worst offenders. Knowing this, I will tell you Japan is 'cold' 4 months out of the year, but where I am at in Tokyo you only MAYBE see snow for ~3days.
5. A certain recent video was deemed...confusing by everyone that viewed it and it is now mysteriously missing...lol
That said...
I live in Japan, and I found a 2004 997.1 C2S in manual with 38,XXXkms. Car has maintenance records from Porsche, full aero kit, Sport Chrono, and a sunroof. It was the first one I looked at,
but I DID look at others...and I simply ended back where I started.
I asked for a borescope before purchase, and I still have not sent funds. The results are in:
- Cylinders 1, 2, and 3 present nothing noteworthy.
- Cylinders 4, 5, and 6 present as follows:
Those two streaks in 5 and 6 are the worst of it.
I now call on the collective power of the 997 Owners that frequent this thread: what say ye?
In my humble opinion having seen many a score .... The concern is not really the two lines but the very early sign of scoring on the second Pic to the right . The fact of the matter is most of our cars have some extent of this and with propper oil changes and start up procedures can mitigate this inevitable for quite sometime . This is the one thing that really enrages me with the brand , that it took decades to finally resolve this defect thru many generations and models and they never took full ownership of it . Shame on Porsche.
Last edited by Space_114 V; Mar 18, 2026 at 10:09 AM.
IMO the heavy marks on #5 & #6 are concerning with only 38,000 KM's or 23,600 miles. However many Bore Scoring issues happen when the engine has less than 60K miles and not surprised it's a 3.8L "S" engine.
You didn't follow your homework and shop for a 3.6L ....Just kidding but will **** off the anti-BSI peeps
If it were me I'd find another example. This scoring is only going to get worse
Last edited by groovzilla; Mar 18, 2026 at 03:17 PM.
In my humble opinion having seen many a score .... The concern is not really the two lines but the very early sign of scoring on the second Pic to the right . The fact of the matter is most of our cars have some extent of this and with propper oil changes and start up procedures can mitigate this inevitable for quite sometime . This is the one thing that really enrages me with the brand , that it took decades to finally resolve this defect thru many generations and models and they never took full ownership of it . Shame on Porsche.
Thats why it's important to get a BSI performed on the 997 engine. It's a bummer scoring happens and imagine paying today's prices for a scored engine
....I've mentioned it many times but shopping for a higher mileage 997 example (70K-110Kmiles) that has little to normal cylinder "streaking" is smart shopping. Why deal with owning a top dollar low mileage/scored engine when it will only get worse and have poor resale value??
Though small, these cars are investments.
Last edited by groovzilla; Mar 18, 2026 at 03:44 PM.
IMO the heavy marks on #5 & #6 are concerning with only 38,000 KM's or 23,600 miles. However many Bore Scoring issues happen when the engine has less than 60K miles and not surprised it's a 3.8L "S" engine.
You didn't follow your homework and shop for a 3.6L ....Just kidding but will **** off the anti-BSI peeps
If it were me I'd find another example. This scoring is only going to get worse
Funny, after seeing some of your posts I was hoping you would reply here haha.
LOL in my defense, I looked. I really did. My criteria is/was:
- 2007 or older due to the timeframe in which I might have to leave Japan to go back to the US.
- Manual. Never wanted a tip car. I DID, however, look at a super clean '95 993 tip and it changed my perspective on them, but still...
- As many factory options as possible. Japan loves air-cooled Porsches, but the water-cooled variants are hard to shop for here.
I would have been open to a C2 if one was available that hit those marks. The closest I could find was a black car for around the SAME price, albeit higher mileage and not in as good condition.
There are a number of pros over on the Porsche Engine Gurus FB group. Have you tried posting there?
Just requested access...coincidentally the video I posted above is from Slakker Racing Development and one of the moderators for that page is the owner.
Funny, after seeing some of your posts I was hoping you would reply here haha.
LOL in my defense, I looked. I really did. My criteria is/was:
- 2007 or older due to the timeframe in which I might have to leave Japan to go back to the US.
- Manual. Never wanted a tip car. I DID, however, look at a super clean '95 993 tip and it changed my perspective on them, but still...
- As many factory options as possible. Japan loves air-cooled Porsches, but the water-cooled variants are hard to shop for here.
I would have been open to a C2 if one was available that hit those marks. The closest I could find was a black car for around the SAME price, albeit higher mileage and not in as good condition. https://youtu.be/4u8IXqQZ3AQ?si=JYvtklY4Au2jQ267
^^^ I stumbled upon this just last night...the 'proof' presented here is worth noting. ^^^
Bottom line is a newbie buyer can do whatever the they want. I come from the position of 14 years ago buying a Bore Scored 2005 997S which was my 1st of 9 997.1's. This was before Bore Scoring was a Topic - The IMS Bearing was the issue topic ayt the time and I had PPI performed at high end Porsche Indy shop in Houston.
The seller who owned the car for 4 years knew damn well the oil burn was 400 miles per qt. - When I called him on it 1/2 way during my drive from Houston to Seattle he got weird and had no answer for me and sounded like BS.
So basically I got Fvcked by the seller who was an RL member.
Instead of burning down his house, I advertized my car for sale and disclosed the oil burn and was able to sell it at a slight but not significant loss.
Those days were over.
......Since that purchase I have Bore Scoped every 997.1 I was buying. (15 BSI's in total) ----->Most results were good but some were terrible and all were "S" engines.
So there you have it. I couldn't give a sh:t about the few RL members who discredit me because I am cautious and truly care about newbie buyers interests.
Only a fool would Roll the Dice buying a 997.1 without a Bore Scope Inspection.
Last edited by groovzilla; Mar 18, 2026 at 09:58 PM.
......Since that purchase I have Bore Scoped every 997 I was buying. (15 in total) ----->Most results were good but some were terrible and all were "S" engines.
So there you have it. I couldn't give a sh:t about the few RL members who discredit me because I am cautious and truly care about newbie buyers interests.
Only a fool would Roll the Dice buying a 997 without a Bore Scope Inspection.
Pulling on your experience with 15 borescope'd 997s, how 'bad' would you rate this?
Knowing that most cars can 'live with it' with a proper engine warm-up, the right motor oil, and changing the oil at earlier intervals than suggested by Porsche (and using your gambling metaphor) what are the odds the pictured 'scoring' becomes a serious issue?
Car is ~$55k, I have still been running searches for 2004-2009 911s in MT just about daily, to include this morning. For Japan, nothing else comes close in terms of price and MT. The disparity here is real: it's mostly GT3s for sale...
Last edited by Hotline_Hachioji; Mar 18, 2026 at 08:05 PM.
Pulling on your experience with 15 borescope'd 997s, how 'bad' would you rate this?
Knowing that most cars can 'live with it' with a proper engine warm-up, the right motor oil, and changing the oil at earlier intervals than suggested by Porsche (and using your gambling metaphor) what are the odds the pictured 'scoring' becomes a serious issue?
Car is ~$55k, I have still been running searches for 2004-2009 911s in MT just about daily, to include this morning. For Japan, nothing else comes close in terms of price and MT. The disparity here is real: it's mostly GT3s for sale...
Hate bursting your bubble but selling that car when the time comes will be a bitch. Scoring is only going to get worse.
**Aso I see it's a very early 2005. The IMS Bearing in the very early 2005's is the smaller more problematic IMS Bearing and you should check and see if it's been replaced/upgraded to the LN Bearing. There should be a Serial# sticker for the upgraded Bearing on door jam or in owners manual or on service record with car. The cutoff for the small IMS Bearing was March or April 2005 production.
Engine serial# is a very close indicator - I wrote up this Document long time ago so buyers of early 2005 can compare to the engine serial#:
997 Engine Serial#-
Here is the IMS size engine# reference info:
3.8L "S" engines with serial#'s up to and including M97/01 68509790 have the smaller more problematic IMS Bearing which is serviceable(Can be removed/upgraded)
3.6L "Base" engines with serial#'s up to M96/05 69507475 have the smaller more problematic IMS Bearing which again is serviceable. ...The larger IMS Bearings were much more robust and very small % of failure- Hardly ever hear of it these days
Hate bursting your bubble but selling that car when the time comes will be a bitch. Scoring is only going to get worse.
**Aso I see it's a very early 2005. The IMS Bearing in the very early 2005's is the smaller more problematic IMS Bearing and you should check and see if it's been replaced/upgraded to the LN Bearing. There should be a Serial# sticker for the upgraded Bearing on door jam or in owners manual or on service record with car. The cutoff for the small IMS Bearing was March or April 2005 production.
Engine serial# is a very close indicator - I wrote up this Document long time ago so buyers of early 2005 can compare to the engine serial#:
997 Engine Serial#-
Here is the IMS size engine# reference info:
3.8L "S" engines with serial#'s up to and including M97/01 68509790 have the smaller more problematic IMS Bearing which is serviceable(Can be removed/upgraded)
3.6L "Base" engines with serial#'s up to M96/05 69507475 have the smaller more problematic IMS Bearing which again is serviceable. ...The larger IMS Bearings were much more robust and very small % of failure- Hardly ever hear of it these days
Oh I'm already planning for the IMS upgrade regardless, but thanks for looking out.
I've sent the images to some shops to ask them what they think. I'm of the mind that there are a ton of people that have scoring, do not know it, do not take care of their cars, and are STILL enjoying them...but I am paranoid in general so I wanted to get other opinions.
Bottom line is a newbie buyer can do whatever the they want. I come from the position of 14 years ago buying a Bore Scored 2005 997S which was my 1st of 9 997's. This was before Bore Scoring was a Topic - The IMS Bearing was the issue topic ayt the time and I had PPI performed at high end Porsche Indy shop in Houston.
The seller who owned the car for 4 years knew damn well the oil burn was 400 miles per qt. - When I called him on it 1/2 way during my drive from Houston to Seattle he got weird and had no answer for me and sounded like BS.
So basically I got Fvcked by the seller who was an RL member.
Instead of burning down his house, I advertized my car for sale and disclosed the oil burn and was able to sell it at a slight but not significant loss.
Those days were over.
......Since that purchase I have Bore Scoped every 997 I was buying. (15 in total) ----->Most results were good but some were terrible and all were "S" engines.
So there you have it. I couldn't give a sh:t about the few RL members who discredit me because I am cautious and truly care about newbie buyers interests.
Only a fool would Roll the Dice buying a 997 without a Bore Scope Inspection.
Groove, I'm not trying to be obnoxious, but simply want clarity on the concept ...
Just to be clear, all of your borescopes and purchases were on the 997.1 cars and NOT on the 997.2 generation. And when you recently bought your 991.1 with 9A1 motor (same as in the 997.2 cars) you did not do a borescope.
Or have I got something above wrong?
I believe the 997.1 (and earlier water cooled) non Mezger motor cars can bore score. I do support you on borescope there. Meanwhile the 9A1 motor may score, but the primary failure there is more likely to be cold seizure (easily mistaken as bore score and possibly prevented with proper warm up procedures).
Streaking is another topic, and I'll leave it at that (refer to Slakker and their findings regarding the reliability of photos).
Streaking is another topic, and I'll leave it at that (refer to Slakker and their findings regarding the reliability of photos).
This is more or less the 'other side of the coin' I was hoping to hear from: after watching the Slakker video you have to ask yourself what is actually scoring on the camera and what is 'acceptable'. Everyone has been taught that n o t h i n g is acceptable.
Last edited by Hotline_Hachioji; Mar 18, 2026 at 09:06 PM.
Groove, I'm not trying to be obnoxious, but simply want clarity on the concept ...
Just to be clear, all of your borescopes and purchases were on the 997.1 cars and NOT on the 997.2 generation. And when you recently bought your 991.1 with 9A1 motor (same as in the 997.2 cars) you did not do a borescope. Correct - The 991 I purchased is a California car. The seller is a Honda Automotive Engineer and did a Blackstone Report 2 months/500 miles prior to selling me the car. No oil burn/no smoke and w/115K miles I had no fears of scoring.
Or have I got something above wrong? Nope all correct---->All my 997's and Bore Scope Inspections were on 997.1 engines
I believe the 997.1 (and earlier water cooled) non Mezger motor cars can bore score. I do support you on borescope there. 100% - I'd never buy a 997.1 without Bore Scope Inspection and I should have made that clear in my above posts and will correct it.
Meanwhile the 9A1 motor may score, but the primary failure there is more likely to be cold seizure (easily mistaken as bore score and possibly prevented with proper warm up procedures).
Streaking is another topic, and I'll leave it at that (refer to Slakker and their findings regarding the reliability of photos) From my observtions/readings on this and various other Porsche Forums/Chat sites, cylinder streaking is normal cylinder wear.
Last edited by groovzilla; Mar 18, 2026 at 09:57 PM.
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Slideshow: Porsche's latest electric Cayenne Coupe blends dramatic styling with supercar acceleration, turning the brand's midsize SUV into a 1,139-horsepower flagship.
One-Off Porsche 911 S/T Takes Inspiration From Famous '70s Race Car
Slideshow: A one-off Porsche 911 S/T created through the Sonderwunsch program pays tribute to a little-known 1970s race car from the Camel GT Challenge.
First 997.1 - Borescope Results - Thoughts?
....Just kidding but will **** off the anti-BSI peeps
