Frequency of bore scoring / Dchunk issues in 996.2

Recently picked up a '05 C4S 996.2 and didn't have an opportunity for a ppi or bore scope. 41k miles with a single row LN retrofit recently done, and runs great, quiet. Now I've been reading so much about these bore issues and starting to sweat a little. Anyone have any stats on frequency of these issues manifesting, as we have seen published about the double row vs. Single row IMSB failure rates?

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welcome and congrats.. 1st. do a search and read more than you have and the answers will come. 2nd. I would still have a PPI done with bore scoped so you know where you stand currently. welcome aboard!

Thanks. If I researched the 996.2 cylinder risks prior to purchase I would have hesitated, requested a ppi, but it was an impulsive auction across the country with good service history. No smoke or slap sound in the 1,700 trip home. I have a good local indy that worked on the 986 I had prior. I'll invest and plan to have him scope it and drop the sump to see the lower cylinders next oil change. It's a tip so not worried about over revs. I guess if there's scoring found there's nothing that can be done without pulling the engine and redoing the cylinders and pistons; can't fund that right now; I'd be very sad.

You’re doomed. Your car will blow up any day now. Your IMSB, AOS, coolant lines, motor mounts, ignition switch, foam in your vents, upper control arms, bushings, RMS, cable ends, window regulators, window drop micro switches and sunroof buttons are disintegrating right now in your garage. You purchased a rolling time bomb. And your headlights are ugly too. You see, my 996.2 has been disintegrating steadily for the last 11 years. Well, not really but I DID really, really, really have to fix the $19.95 ignition switch. Uh, the foam in the vent thing too! PS. New IMSB, clutch and components this spring at 80,000 miles. Clutch was toast. IMSB was just fine. No ticking, no scoring, no nuthin…. I’m kidding. There are wonderful, wonderful people on this forum who sincerely want to help and these stupid little cars are a joy to own, operate and occasionally fix.

Thanks for lightening up the gloom. I spent a year collecting foam in my '99 986. I just read through the thread IMSB vs. BS. A lot of humor and fear and loathing. It is what it is, drive it like it was meant to be, enjoy the ride, maintain what parts you can without pulling the motor and pray. Maybe check the bores so you know you're good for now and sleep well, or find out you're on borrowed time and fret.

JJ, Welcome to the 996. You can sleep at night, the M96 engine is pretty damn durable. Everybody has a different take on what to do and when. Here is my approach to the 996.2. I have had my 02 for almost 21 years next month. It has 59k miles. I tracked it for 14 years as well as drove it on the street and highway. Haven't babied it, but i have serviced the hell out of it. The main reason is that I want to know when I drive the car on the street or track that it will deliver. It has never broken down on me. But it is a 20 year old car, and metal, plastic, rubber wear down, so I replace things at various intervals. There are 4 main risks to the 996.2 engine which are easily solved that are listed below with the preventative solution. Check your records to see what has been done. If it hasn't been recently, you should consider it. 1. IMSB Failure. Replace with LN Retro or LN Solution. 2. Water Pump Blade Failure. Replace oem water pump with a new oem one every 5 years or so. If not, a broken plastic fin will create problems within the engine by getting lodged in places you don't want. 3. AOS Failure. Oem AOS is brittle. Failure can lead to intermix, hydralock and lots of oily smoke. Replace with UAOS Track version. 4. Bore Scoring. Caused by infrequent oil changes, inferior fuel, bad start-up procedures, poor running fuel injectors, etc. So make sure you change your oil at least 2x a year, run good fuel, run fresh fuel injectors, maf, ignition coils amd plugs, as well as use FSI/LNs start-up procedures. Plenty of yutube videos on it as well as discussions here on RL. If you want to see if you have any bore scoring or other issues in the engine, I would recommend doing 3 things. (1) start testing your oil. The tests will tell you what is wearing. Good to know. If it's good, then you are probably good. But keep checking every year. (2) drop your sump and see what in there. Check your oil filter as well. If it's clean and clear, you are good. (3) have your bores scoped to see if you have any scoring. If they are clear, you are good. But listen closely on this one, change your oil at least 2x a year. Quickest way to bore scoring is you don't change your oil enough. My bet with your miles is you are good. But no harm in doing the above. Best case, you keep your engine functioning in top form. Worst case, you find a problem amd can start preventative procedures. Either way, the 996 is more than worth it.

Thanks for taking the time to run down all those suggestions! I have shop records from the 3 POs that show the AOS, plugs and coils, and an LN IMSB retro have all been done within the past 6 years, 7k miles. The oil change records are mostly annual and maybe a couple of gaps I can't account for. I will take the advice and get the sump dropped next change and bore scoped, water pump changed, injectors done. Love the car! I am surprised how stiff the 4S ride is compared to the Boxster I just sold. Feels like I think a hi perf sports car should ride though, not a luxury car! The wide body work looks great, timeless! I saw a video by Pinky Lai on the body design and focus on aero in the wind tunnel. I think the lines are awesome; had to get one while I can still get in and out of it, being 70 years old!

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It is a gorgeous car and a keeper! Enjoy.

Jjcrawdad, Welcome to the 996 world! If there are no records of replacing the tranny fluid and filter you may want to have it done. The 996.2 uses a Mercedes 722.6 tranny, so luckily, internal parts are mostly readily available through channels other than Porsche. Make sure you bring it to a Porsche shop that knows how to change and refill it properly, as of course Porsche has a complicated refill procedure. Also, make sure they use the correct fluid (not universal import car tranny fluid). Have a shop check cam deviations, fuel numbers, and other diagnostic info to get an idea if you need any maintenance (like variocam pads, cam chain pads or tensioners; etc).

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I have a 2005 C4S purchased in 2014 and am now 72 yo. So I can relate to getting in and out. On 4S ride quality tire pressure make a huge difference in ride quality. Owners manual pressures will break teeth on streets. I run 34f and 40r. Really softens the ride for this old dude and haven't seen any unusual tire wear.