Need some advise on a 03 c4s, please!

I have had a 993, 991, but never a 996 C4S. I need advise to look out for issues that are common on these cars. My 993 has issues of its own which ended up costing a ton to fix. My 991 was trouble free! Thank you!

The best advice would just be to either buy a 1999 C2 or a 996.2 Turbo. C4S has all the weight and nothing you really want. For the money a nice C4S commands, I'd much rather end up in a slightly less nice Turbo and not have to deal with a $15k M96.0 time bomb and having two pointlessly driven front wheels.

love my 996 C4S it is my favorite driving car I've ever owned, including other 911s. Things to look out for are consistent with the other M96 engine cars, so you'll want to check that the IMS bearing has been replaced, or you should do so upon acquiring. The other bogeyman is bore scoring, which you can rule out by scoping the bottom of the cylinders from the sump. A warm weather car with regular oil changes is less likely to have scoring. Other than that I cannot think of anything. Many of them will have little cosmetic things, like cracked taillights is incredibly common. Black foam coming through the hvac vents. And then there are the things going out with age, like the window regulators will likely be busted. Water pump and thermostat replacement seem to be a common preventative maintenance item, and many people upgrade the AOS to the UAOS. The problems are all well known and documented and most have an easy fix.

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Thank you! Is there any way to tell whether the IMS bearing has been replaced? Are there any signs to look for? Thank you! The car has been in the PNW for all of its life and maintained by the dealer.

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I believe you'd need the engine or trans out to 100% verify if the IMS has been changed. People usually do it when they replace the clutch. If there is no invoice/proof it it being done I'd assume it's original and should be done.

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What is the cost of getting the IMS changed?

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Usually $1500-$3000 depending on labor and if you do the clutch while you're in there.

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Thank you! I am getting a PPI and see what turns out, so I need to budget 3k! The car has 58k on her! I remember knowing how to test my clutch in my 993...that was many years ago!

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If you're lucky, might see an extra aftermarket oil line going to the imsb and you'll know...

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Since you will be in the area, consider testing your oil, drop the sump to see what's in there, check the oil filter, and scope the bores as well. If all checks out, next step is imsb, rms, check the clutch and flywheel. If you are feeling your oats, might as well do the uaos, spark plugs, coils, fuel injectors and the water pump. Then drive the hell out of it.

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Yeah, except for the fact that was the faster NA car of the 996 range (non GT cars) or that was considered by most of the specialized press from the era as "The best 996, second only to the GT3"... To the OP. Make your due diligence before the buy, as with any used car: ask for maintenance records (the most well taken care, the better) and do a PPI if possible. If everything seems ok, go for it and assume that they are all 20+ years old cars and past reliability does not guarantee future reliability

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IF you're referencing the ring time, that was only due to the upgraded tires that came on the C4S vs C2. All things equal the C2 wins every time. Adding 200lbs and more driven wheels when the car isn't traction limited by power only makes for a slower car.

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FYI to the OP: this is highly opinionated. C4S 996's are highly sought after and good ones bring a price premium. That doesn't happen if they're bad cars.

Another point of view about the C4S awd. 1. It's the same suspension as the revered Turbo. 2. The added front weight helps balance the rear engine weight bias, yielding superb handling (especially on track). 3. TRACTION in all situations.

I forgot to mention - 4. The best butt of all 996s!

Hahaha... I would buy any model 996 in any year that makes you happy as long as you thoroughly vetted it. All are good choices if the engine has been well taken care of and in solid shape. But isn't that the same for any 20 year old car? Even one powered by a mezger?

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Like the C4S, the 996 Turbo is an AWD system. OP, the 996 Turbo along with GT cars, are some of the last to see the Mezger engine that doesn't suffer from the same failure modes that plagues the Carrera M96 engines. Unfortunately, the C4S has the same core engine has other Mk2 Carreras - M96.03 are well-known for two serious modes of failure - cylinder bore scoring and IMS bearing failure. Here are the bank2 pistons out of my 2003 C4S M96.03 engine. This came from a one-owner car that was regularly maintained by Porsche dealerships even after warranty. Not trying to scare you away, but this is the reality of a 20 year old Porsche 996 Carrera. If you find a good examine, get a PPI which includes bore scoping.

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You Tube

I've had my 03 C4S Tip for almost two years now. If there's any buzz in the cabin on startup or in turns, you're likely looking at motor and or gearbox mounts. Mine had a noticeable buzz from idle up to highway speeds. Replaced the motor and gearbox mount (the old bushing in gearbox mount fell out when it was removed) and all of those weird noise disappeared. It's like a brand new car. Might also check on the health of the front right and left radiators. Mine started to leak at where the line in is welded. Replaced them both with CS4. A bit more spendy because they are common to the TT. Also pulled the trigger and did the IMS. Went with the EPS bearing on recommendation from my indie. Old bearing (at 92k miles) looked fine. Still glad that I did it. Cost about $2500.

If the car has " always been maintained by the dealer " then they can tell you if/when the IMSB was replaced . And any other maintenance history . Should be a simple VIN # check . That along with a thorough PPI should give you the info to buy or run away .

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Porsche doesn't consider it a service item nor is there is not a part# assigned to the actual IMS bearing and unless the previous owner specially requested it, more than likely was not handled preventively by the dealership. I agree, it's still a good idea to double check.

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Bore scoring is not an engine issue. It is caused by human error. My bet on this engine is as follows. The owner did not properly service the engine. Instead he changed the oil every 20k miles instead if 2x a year. Probably ran the same spark plugs, ignition coils, fuel injectors for 20 years as well. Probably also just drove the car to and from the grocery store a couple of miles at a time. So he got bore scoring. Oil probably wreeked of gas. But if he changed the oil at least 2x a year, ran fresh plugs, coils and injectors, replaced his MAF, not to mention drove it at higher rpms and did a DE or two every so often, that engine would be in great shape. The M96 engine is solid as hell if you service it properly. Therefore, when looking for a M96 powered 996 to buy, get the service records. No service records = no proper maintenaince = high probability of bore scoring = a car that you dont want. Service records = confirmation to test oil = confirmation to get a PPI = confirmation to get a bore scope. When you find a good one, buy it. You will be glad you did.

In the 4 years (42k miles) owning my 2003 4s I've done the following: LN IMSB Retrofit RMS Clutch Coil packs/Injectors Water pump Starter Window Regulator (2x) Horn Alignment 997 GT3 Shifter Motor Mounts UAOS Replaced Front Differential Brakes/Pads Upgraded Radio/CarPlay K40 Radar detection Fabspeed Sports Cats

I guess as long as it's not a Cab or you can also expect a cracked head / intermix

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The "human error" was a corporate accountant that convinced the corporate heads to make compromises to save $$$ and appease the environmental government regulators that weren't done on upper end M96 engines.

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Well aware, but at 420 hp you could make a case for driving the front wheels. The C4S is a fine car, just at the bottom of the 996 lineup for me personally. All 996s are good.

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Absolutely. Don't forget it was also Mobil convincing Porsche that the car could go 20k on every oil change. Or maybe Porsche convincing Mobil. 🤔 Not to mention the geniuses who designed and decided to use the oem AOS in the car then the engineers who suggested to run the car low on oil so the AOS didn't fail. Long line of knuckleheads. Hope you and all others dont misunderstand my comments. After 20+ years we have identified the issues and solutions for each issue. But the key to finding a 996 to buy is to understand the issues and solutions. Most importantly, check the engine and bores before you buy. If it's in good shape, all you have to do is properly service it with all that we learned from FSI, LN, Hartech amd countless other folks in the industry over time. If it's not in good shape, run as fast as you can from it. But you gotta check...

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I'm afraid you'd lose this bet. I know the family and stay in touch with this family. The car was his daily driver and had well over 100K miles before the owner passed away. He believed in short drain intervals and preventive maintenance over and above what the factory recommended at the time. The car was maintained flawlessly inside and out... even won many PCA concours events. Because of the class action law suit, they became aware of the IMS bearing problem and made plans to have it replaced. Unfortunately, cylinder bore scoring was not a topic at Porsche and so it wasn't something the family was aware of at the time. (This was also before Jake Raby and PCA released any information on the topic) They didn't realize they had a problem until they started getting misfires after engine out service. They scoped the cylinders and it was obvious they had a serious problem. The rest is history.

No question we will see more oem IMSB failures as these cars put in more mileage as well as bore scoring occurring. Just a fact of wear and tear on metal over time. Probably never know with perfect hindsight what variables lined up to cause his borescoring. But after 21 years and 59k miles on my 996.2 with lots of track days, local driving and oil changes every 700 miles and plenty of fresh parts every 5 years or so (fuel injectors, spark plugs, coils, MAF), very few short stints to the grocery without a longer spirited run, and in a cold weather town, i dont have any bore scoring. But I am keeping close tabs to see if and when it develops. All out of curiosity knowing sometime in the next few years I will get an elective rebuild for more performance. With or without bore scoring. My bet is I won't have any.

I'll chime in as another "vote" for the C4S. Heavier? Yes. M96 limitations? Yes. But I find the aesthetics to be the best of the 996s. I like the wide body, the full heckblende, and the lack of spoilers and intake vents just make the lines the best in my opinion. I daily drive mine and absolutely love it.

So how do we explain 911user who is getting close to hitting 500k miles on his original motor and looks like his recent service showed cylinder walls to be in great shape with no scoring. I think I've read somewhere he's been using Mobil 1 0w40 too I personally like the C4S and spent 3 months with it before buying my 40AE. I get why people like the wider hips and I also like the red stripe across the rear lid. I was quite surprised with how different the steering felt to me compared to a C2. I just preferred it. All said and done I found more value in having an LSD, X51 and the sport seats that my car came with over the wide body. You can read the internet till the cows come home but nothing compares to getting seat time in the car. Can't suggest enough getting a ride or asking someone to let you drive their car. I've done this prior settling on my suspension. Porsche folks are generally pretty open and happy to help so it never hurts to ask!

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That is one of the mantras repeated here in RL and that has actually harmed a lot the 996 reputation: that the 996 was bad because it was made cheap. When the reality is totally the opposite. And that is also, a statement that only shows a lack of knowledge of the history of the brand, during those years and in particular of the development of the 986/996 project I invite you to read some historic books from that era, and investigate how porsche invested all that they had (and what they didn't) in a all or nothing movement to develop two new cars from scratch, investing 1billion of dollars (of 1994 dollars) That the M96 engines are not as strong as the old air cooled is obvious, as any high performance modern engine of the era (look at ferrari, bmw, etc) can compete with the robustness of the AC engine and as the AC technology can't compite with the WC in performance (that's why they are not in use anymore). But the 996 was a 911 with such much improvement in all the areas, chassis, performance, security, technology, comfort, aerodynamic, efficiency, economy. I invite you to read also about what Porsche internally thought about the 964 (specially the Carrera 4) and how that was the main reason that take them to think that the 911 concept was at the end of its development. And also, read about how that actually made that the 993 development was the one really limited in budget, as a "last chance" and thanks to the genius of Bez and his team, made them to rethink that idea, (despite being seriously limited in budget, avoiding their creators to implement things that they wanted to do, as a water cooled engine, change the interior, or the roof). The success of the 993 though (commercial, but mostly in terms of driving performance) was what convinced them to invest all in a totally new 911.

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Another old mantra from RL. No it was not only for the tires. In fact, there is no proof of that. However, the C4S is not just "more weight"... is also more track width, is also more tire section, is also more sport tuned up suspension, is also more brake power and more traction to go sooner on the throttle. To give some perspective, lets just take a look to the EVO Magazine car of the year. The 996.2 was 6th in 2001 while the C4S was 2nd in 2002 (just 0,3 point behind the radical NSX-R). But more important, the impressions and comments from all the editors regarding what really matter most to understand how the cars were perceived in terms of driving experience and engagement.

Please explain to me how adding more drivetrain loss and weight makes a car faster. Making a car wider does not make it faster. The base 996 is not traction limited by power -- same reason why putting a LSD in a C2 isn't that big of an upgrade. C4S looks nice from a couple angles, but outside of that it's a worse car than a C2.

Hey brontosaurus. What do you stand to gain by continuing the "better or worse" argument? You're railroading the thread, discouraging the OP, and offending every polite, considerate C4S owner who is trying to offer direct help, or counter your negativity. You may want the Maris or Mantle post.

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Consider it more of a psychoanalysis than a mantra. Hate to break to the news to you, but while the 996 was a step in the right direction, it was made on a budget because Porsche was bleeding funds badly and needed a lifeline. That statement clearly sums up Porsche in the mid-90s when they were trying to squeeze what little life they had left out of the aircooled engine. They couldn't get anymore power nor could they fulfill the more stringent environmental regulations. I own and have plenty of historical books on the Porsche 911 and the transition from aircooled to modern water cooled cars that happened with the Boxster and 911 models during the 90s. However, some of the most revealing details have not comes from the books, but from actual interviews of the corporate heads and designers at the time. Let me give you one popular example of a corporate compromise... the notorious "fried egg" headlights. While many would say it's a carry over from the GT1, but the reality is they had to cut costs and so designers like Pinky Lai designed a headlight enclosure that had integral turn signals, fog lamps, markers, and washers in addition to the normal low and high beam lighting. While many people didn't like the non-iconic lights, it saved Porsche millions. As history has told us, with the success of the 996 and 986, Porsche appeased the purists and returned to a more iconic look and design with the 997. Now that's just one example of many more including the rear retractable wing. The bean counters wanted it removed because of costs, but Lai found a way to design it within budget but it required some compromises, but history has shown those wings held up unlike other things. We could talk about the engine compromises on the Carrera M96 engines all day long.... When they moved to Lokasil from Nikasil - that was compromise! When they moved from oil-fed plain bearings that supported both ends of the IMS to a cheap $20 wheel bearing to support one end of the intermediate shaft - that was a compromise! When they designed a "intergraded dry sump" instead of a true dry sump oiling system - that was a compromise! When they used the same piston offset for all pistons - that was a compromise! When they used cheaper, less durable components (e.g. rod bolts) - that was a compromise! When Porsche moved to integral cylinders instead of removable cylinders - that was a compromise! When Porsche moved to Ferraprint from Ferrostan - that was a mistake and possible compromise D-chunk, intermix, AOS failures, RMS leaks, IMS failures, bore scoring, etc.etc. on and on it goes... There are a lot more, but I must get ready for work. With all due respect, you need to re-read your history books or find new ones. There are actually TWO BIG reasons for moving away from aircooled engines to watercooled in Porsche - 1. environmental Fed/EURO compliance 2. power threshold of aircooled technology I'll add another one IMHO - 3. THEY WERE LOSING FREAKING MONEY!!! They had to make a major change or it would mean they'd end up like lot of smaller car manufacturers... possible take over OR dead in the water. What was the result? Watercooled engines - new sports cars - Boxster and new 911... and SUVs (i.e. Cayenne) on the horizon. Yep... the SUVs were a big part of the equation that saved them in the long run. Definitely agree there was a lot of notable improvements. I've read all that thank you. I have the book on the subject. I also encourage you to watch actual interviews to hear first hand what was really going on at the ground level. Read about the possible take over of the company and them hiring Toyota engineers to help change the factory production system. I stand by my comment, while harsh, does sum up what going on at the time. You may think I hate the 996, but NO... it's still my favorite in spite of all the crap that came with it. I've owned two of them and plan to own another.

Not certain how everyone reads the tea leaves, but I see a car (996) that is in hot demand because every issue has been identified and affordable preventative procedures and solutions have been developed to address everything. Be glad you don't own a 20 year old Ferrari, Lamborghini, Maserati, McLaren, etc. They are quite a bit more expensive to maintain. What's not to like?

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I'm sorry if making a reasonable case as to why someone might rather buy a C2 is offensive to you.

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It actually can. Not saying it does in this case. But this statement is false.

Thank you Gents for all your input! This is what I know so far, it need a new front differential, IMSB must be done, likely needs a clutch, engine and transmission mount must be done! Walking away from this one, unless the price is reduce for the work I mentioned.

So,, just to toss a thought out there,, if AWD is no advantage, why is it illegal in nearly every upper end road racing venue.. ?? IMHO the viscous coupling Porsche chose was a compromise, the diff should have been bigger in the front and it needed more durability and more front bias to handle inclement weather.Basically a wet and dry mode.. In the rain in the curves my C4 is amazing, way easier to push limits in than my buddies C2. I also like the feel of the power coming on in the front out of a turn.. I would not kick the c2 out of bed but either of them are variations on a theme..

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On this site newbies always ask "How can I make more power". The answer always is you don't need more power. Get a better suspension, wider tires, and bigger brakes to go faster. That's what the C4S does. More weight isn't always bad. It matters where the weight is. Drag racers have known this for years. They add weight to the rear of the cars because they need traction to the rear tires. Well, the weight added with AWD is in the front which adds more traction to the front wheels on a rear-heavy car. What people also forget is that the body is stiffer. That allows the suspension to do its job better. That is why the GT3 used the AWD body. The C4S is about traction and using the available power. Here are 1/4 mile times from this site https://accelerationtimes.com/makes/porsche . A tenth of a second is negligible. So it's basically a dead heat. So the C4S is as fast as the RWD with 200 extra pounds. The difference is traction. C4S 13.9 s @ 114 mph C2 14.0 s @ 114 mph I am not posting this to argue over what someone likes the best. That is a matter of preference. But to say that the C4S doesn't handle as well or isn't as fast as a RWD 911 is utter BS.

The chassis rigidity was not the only reason for choosing the AWD chassis for the GT3 variants, I’d also argue, with the modifications done to the racing car's (and I think the GT bodies had selective additional welds from factory) it was also the less significant to performance when compared to the other reason. The AWD chassis allowed for the space to get a larger fuel cell through homologation. My uneducated opinion is this was the principle driver of the chassis choice.

I enjoyed driving my C4S and the handleing was great. I think I recall the C4s being descibed as a "sheep in wolfs clothing" by the Top Gear guys.

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I'm one of the legion of souls who will likely never be a good enough driver to NEED more power from my C4S. (Just as I will never be fast enough or fit enough to NEED more bike!) My journey with my 996 is to make her truly "mine" and to enjoy the experience along the way. Communities like RL are great to enhance the learning process and the overall experience.

Bought mine with just over 100K miles as a weekend driver. Previous owner had the ceramic IMSB - not The Solution - installed at around 80K when clutch was replaced. Lived in the Atlanta area all its life Pros. Handles like a dream and plenty fast for me. 6-speed manual - avoid Tiptronic IMO. Best looking naturally aspirated 996 with the wide body. Cons. Current going through the foam blowing out the vents. The frunk is smaller than RWD 996.

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Absokutely. The 996 is plenty fast. Every novice driver I have instructed over the years will always say that they wished it had more power. I would always tell them that the car is extremely fast for its time period as well as against the modern 911s, but you have to learn how to drive it. After two sessions with them, I would take them out for my third session with the instructors and Club racers. Every one of them would say something like, "I had no idea the 996 was that fast". And I would say, Yep.

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Because I've grown up in the muscle car south, I have to change the way I explain things because most gauge things on the quarter mile or Waffle House menu. I tell them that Porsches are "quick cars" made for the race tracks, not drag strips. So many muscle cars would beat the porsches in the straight line quarter but would have their asses handed to them on a platter when trying to race on a track.

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You nailed it. Two different skill sets and and car requirements. Never got into drag racing and never cared about 0-60 or the quarter mile. Completely different than speed and skills needed on the track to brake, balance and turn the car.

Its like a Lotus 7 at a track day,, 100HP and on a tight track in the turns it's eating up cars with 4x the horsepower. We have a local track day guy with one that is just fun to watch... LOL

One of the funniest times I had on the track was around the mid 2000s. Two guys had bought an ALMS raced Dodge Viper and were DEing it at our local track during a PCA DE. The Viper was incredible in looks and sounds. Not to mention extremely powerful and fast in a straight line. The problem was that it didn't turn well and so powerful when coming out of a turn that the guys couldn't control the car. It was all over the place and was wreeking havoc with the other drivers. They were eventually moved to a slower group and told to slow down and learn how to drive the car. They may have been excellent drivers, but the car wasn't made for a tight 2 mile long track. In fact, I remember watching the car at the ALMS races at Road America a few years earlier. Car was powerful, fast but couldn't turn at Road America either. Incredible car even though it couldn't turn. The sound was incredible.

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On the front differential issue, you can just remove it and convert the car into RWD, my C4S is this way, PO removed the front differential for some reason, he did gave me all the parts, one of these days I am going to connect it all back on and see how the car handles. I track the car and yeah it can be a bit lose in the rear on turn exist but it is manageable, with good tires it drives very nice. I replaced the clutch myself and was not any harder than any other clutch job. the engine mounts was a very easy job for a DIY.