The sixth-generation 911 with the internal code 997 was an evolutionary update of its predecessor, the 996. This means that much of the buying advice for the 996 also applies to the 997, especially the 997.1 (pre-facelift) model. The 997.1 differs from the 996 mostly in terms of sheet metal (including the return to round headlights with separate turn signals/fog lights) and a much nicer interior. The base Carrera model used basically the same 3.6l engine as the 996.2 (now designated M96.05 and with an additional 5hp for 325hp total), the S used a 3.8l with 355hp. With the facelift in 2008 (2009 model year), a whole new engine generation with direct fuel injection was introduced.
The buyer’s guide below is compiled from many sources on the internet. It aims at the 997.1 Carrera 2/S models, but most items are also relevant for the Carrera 4/4S and the 997.2.
Options
Make a list of must-have and should-have options. These cars were pretty bare-bones without options. A/C was standard, cruise control was not. Automatic headlights were not available, automatic wipers were an option. Partial leather was standard. Black interiors are wanted now, a light interior might be cheaper. The vast majority of cars is black, gray/silver, or white, other colors may command a premium. The S came with the round sports steering wheel and adjustable PASM suspension. This means that the true sports suspension (which included the limited-slip differential) is rare. Sports seats are probably a plus, but might be a tight fit for some people. A common option is the sunroof – you might like it if you want a weekend cruiser, someone who has track use in mind will probably want a car without sunroof. PCM was standard, navigation, CD changers, and phone module were optional. I would also put the leather package pretty high on the wishlist as this is much nicer than the standard interior.
Aero kits, especially GT body kits, exist – some are factory, some are aftermarket. This is a matter of personal taste.
Maintenance record
A complete maintenance record/service history is the most important piece. If an owner has avoided the relatively expensive maintenance, walk away – chances are that the car has undetected issues that will prove costly in the future. Check especially for the items that are lots of work, such as the clutch and rear main seal.
Pre-purchase inspection
Consider having a pre-purchase inspection done at an independent Porsche specialist. This will cost a couple of hundred €/$. Even if you have prepared yourself with all the knowledge available on the internet, a specialist will know more and has specialist equipment to give the car a more thorough inspection, and prices for necessary fixes that you can use in your negotiations with the seller.
Exterior
Rust is generally not much of an issue, but check usual suspects such as the wheel arches. The hood (or is it the trunk?) may have stone chips. Make sure the headlights are Ok as they are expensive to replace. The folding bellows under the rear spoiler may crack,.
Engine
The 997’s M96 /M97 engine is the part of the car that may cause the most expensive issues. A full engine rebuild can easily cost upward of 15k. Over the years, several potential issues have surfaced.
IMS bearing
Much has been written about the intermediate shaft (IMS) bearing. The GT3 and turbo models are not affected. The early cars have a small single-row bearing that exhibits a relatively large failure rate (somewhere in the 5-10% range), without prior warning, usually resulting in catastrophic engine damage. In 2005, Porsche moved to a larger single-row bearing that exhibits a very low failure rate.
This means that if a car has the small single-row bearing, replacement is recommended. There are aftermarket bearings available that are more reliable, but these should be considered routine maintenance items. There’s also a permanent solution (or at least advertised as such) by LN Engineering, which converts the sealed ball bearing into an oil-fed journal bearing (just like the front IMS bearing). The larger single-row bearing can only be replaced after complete disassembly of the engine.
It is said that it can be determined based on the engine number whether a small or large IMS bearing is installed. Engines with serial numbers M96/05 69507476 and up (3.6l) and M97/01 68509791 and up (3.8l) are supposed to have the more reliable larger bearing.
If you buy a car that is likely to have the small single-row bearing and there is no evidence of it ever being replaced, take the necessary costs into account. If you have an IMS bearing replaced, have the rear main seal and clutch done at the same time.
The 997.2 engines have no intermediate main shaft and thus don’t suffer from these issues.
RMS
The rear main seal (RMS) is located at the transmission end (i.e. towards the front of the car) of the engine, and a common point of oil leaks. Replacement requires removal of the transmission, so take this into account if the engine exhibits an oil leak at the engine/transmission gap.
Bore scoring
This is the other big issue with the 997.1’s engines. The causes are complex and consist of manufacturing defects, overheating, and poor lubrication. Tiptronic cars appear to be affected more than manuals, and 3.8l engines more than the 3.6l. A PPI should include borescope checks of all cylinders. As bore scoring starts at the bottom of the cylinders, this should be done from the carter pan, not the spark plug holes. Blackened exhaust tips on one side (probably the left, as the right side of the engine that feeds into these is more prone to overheating) and ticking noises from a warm engine point to issues, too.
Fixing bore scoring properly is expensive. Many companies employ steel liners, but this can cause issue as these have a different thermal expansion coefficient than the aluminium block and pistons. The recommended solution is to place aluminium sleeves, possibly converting the engine from open deck to closed deck in the process. This can be combined with an increase in displacement.
There haven’t been many reports of bore scoring issues with the 997.2.
Air-oil separator
A failing air-oil separator (AOS) will be noticeable by exhaust smoke and sludge on the oil cap. This can cause big issues, so the AOS should be replaced regularly.
Coil packs
Coil packs are a common issue with modern cars. In the 997’s tightly packed engine compartment, they sit close to the exhaust. Make sure that they are Ok and that the heat shields are in place.
Exhaust
The mufflers are directly behind the rear wheels and hence constantly bombarded with whatever is on the road. They start rusting at the seam of the two halves. The stock mufflers are relatively quiet, so if a muffler replacement is due, you may consider an aftermarket exhaust if that’s your thing.
Both exhaust tips should look similar. If one is blackened while the other is clean, this points to issues with one cylinder bank – walk away.
Clutch and transmission
Check whether the clutch is slipping, try to find out when it was last replaced. A heavy pedal is a sign that a replacement may be due soon. A clutch job can be combined with the IMS bearing and RMS, as all three require the removal of the transmission.
The 997.1 has a new six-speed manual transmission by the Japanese manufacturer Aisin, I have not heard about specific issues with these. The Tiptronic automatic is the same five-speed unit supplied by Mercedes as before. Most 997.2 cars have the new PDK double-clutch transmission, I’m not familiar with its reliability record, but given the problems that Volkswagen has with the DSG transmissions (burnt clutches), I’d be careful.
HVAC
Thanks to the water-cooled engine, the 997 has much better heating than its air-cooled predecessors. Air conditioning was standard. The condensers are mounted op front in the left and right corners. Leaves can collect here and rot, which will cause leaks in the condensers. Make sure that they are in good condition and that the A/C works properly. The coolant lines on the bottom of the car should also be checked for corrosion. The same is true for the radiators, which are located here as well.
Interior
The 997 interior is nicer than that of the 996. The leather package will make the dashboard look and feel nicer than the standard plastic version. Optional trims were aluminium, two types of wood, and carbon. The soft touch paint is prone to chipping, the PCM knobs are especially problematic but can be bought separately. The lighter interior colours (especially sand beige) will show more wear than black.
If the car has interior wear, take this into account in the price negotiations. A common solution for a scratched center console is painting it either in flat black or the exterior color.
The PCM 2.1 system of the 997.1 has no provision for Bluetooth or an AUX port. The cheapest option to add these is the Mr12Volt module, which requires eliminating an existing CD changer and phone module. If you want a more modern option including CarPlay/Android Auto, there are several third-party options available, and Porsche’s own PCCM+, which is quite expensive.
Suspension
Suspension arms, bushings, and shock absorbers are wear items. Try to find out when they were last replaced. Drive the cars over speed bumps and listen for creaks. Check the shocks for signs of leaking. If you plan on doing suspension work, consider upgrading to decent shocks, or a good coilover set – especially when you want to use it on track. The non-PASM cars sit quite high. PASM cars come with stiffer springs, and the ride in sport settings appears to be quite harsh. If the rear bounces in comfort setting, new dampers are in order.
Brakes
Unlike some other brands (looking at you BMW), Porsche equips their cars with excellent brakes. The downside is that dealer-supplied replacement parts are relatively expensive, so make sure to check that rotors and pads are in good condition. Brake hoses may become brittle and brake lines rusty, so check these, too.
Wheels & tires
The car should be equipped with Porsche-approved N-rated tires that aren’t too old. If that is not the case, as the owner wanted to save money, he may have taken shortcuts elsewhere. Tires aren’t crazy expensive, but the rears wear quickly. The wheels should be in good condition. 18″ was standard on the non-S cars, 19″ on the S, several wheels were available as option. Some people downgrade to 18″ for a smoother ride.
Conclusions
A well-maintained 997 is a reliable and quick sports car that offers an analog driving experience (it is the last 911 with hydraulic power steering) without sacrificing modern comforts. Prices will probably rise in the future, so depreciation is no longer an issue. If you worry about the engine issues, make sure that you get a car with the larger IMS bearing and have it checked for bore scoring.
The 997.2 will offer more peace of mind in this regard, but as a result they are quite a bit more expensive. They are also rarer as their production run coincided with the financial crisis.
As always, you should prefer a car with full service history above a low-mileage car that has been neglected. I would also consider a revised/rebuilt engine a plus.
Common wisdom is to buy the best car you can afford, but I would consider an early (1998 or ’99, with the dual-row IMS bearing) car with >160,000km (100,000 miles) and a complete service record instead. Such a car should have lots of work done already and could be more reliable and a much better deal than a low-mileage garage queen with skipped services.
The 996 is actually a car that you can work on yourself. Yes, most engine work needs to be done from underneath, but the engine is exposed at the rear and accessible once the car is on jack stands. There are people who have done IMS bearing replacements in their garage. As is typical for Porsche, part supply is not an issue. So if you are on the fence about buying a 996, do it – it’s a future classic.