The engine and gearbox of the 996 Turbo are directly descended from the air-cooled 993 Turbo's, though the 996 has water cooling and a six-speed manual gearbox. This has the distinct advantage of avoiding many of the problems and weaknesses associated with the standard 996's M96 motor.
For the 996 Turbo, the flat-six engine has an exact capacity of 3,600cc and comes with twin KKK turbochargers and four valves per cylinder. This creates 420hp at 6,000rpm and 413lb ft of torque at 4,600rpm. For the X50 option and S models, power increased to 450hp and 457lb ft at identical revs with help from a modified ECU, uprated turbos and intercooler. A six-speed manual transmission was standard, with a five-speed Tiptronic automatic gearbox an option for all derivatives. Four-wheel drive was a fixture for all Turbo models. If you wanted rear-wheel drive, you would have to go down the GT2 route.
Enthusiasts prefer manual, market less bothered
Although the Turbo's engine is essentially very robust and reliable, there are some basic precautions to make. First off, any car you consider must have a full and comprehensive service history, either from Official Porsche Centres (OPC) or known specialists. Budget on changing the spark plugs every 24,000 miles or two years, and reckon on spending £4,500 per year on servicing and replacement parts for a 996 Turbo in good condition with average miles. The spindle in the turbocharger's wastegate can seize, which leads to excessive boost pressure and can permanently damage the engine. Fortunately, this is simple to sort out.
The engine has recommended oil services of every 12,000, but changing the oil and filter at 6,000 mile intervals will help prolong the engine's life. Checking the oil level is by a digital display on the dash rather than by dipstick, so it can be tricky to assess the condition of the oil before buying. Oil changes are further complicated by the engine having four drain plugs - one in the engine itself, one on the reservoir and one for each turbo.
There should be no oil leaks with the 996 Turbo and it doesn't suffer the intermediary shaft woes of the normally aspirated 996 models. If there is any oil evident, it's probably from the output shaft seals, which are relatively simple to replace.
You may hear some cam chain noise, identifiable as a whirring when the motor's cold. If it disappears when the engine is warm and revved to around 2,500rpm, there is no immediate danger. However, it is an indication of future trouble, so it might be wise to look for another car. Another source of an oil leak can be between the cam carrier and cylinder head, which is straightforward to cure but requires the engine to be removed, so labour makes it a pricey job.
The exhaust can rattle, which is most commonly the heat shields working loose. Replacements are available, but many owners choose to fit an aftermarket exhaust for a little more power and, importantly, noise as the 996 Turbo is often accused of being too quiet for a supercar.
A servo assists the clutch, which can make it more difficult to spot a failing clutch through pedal feel. However, the clutch is strong and should last 40,000 miles before needing a replacement unless the owner is very abrupt when engaging the clutch. Fitting a GT2-spec clutch is a common upgrade. Beware failed hydraulic accumulators that will be obvious by a stiff pedal action. Tiptronic 'boxes are tough and reliable, but make sure the electrics work and the steering wheel buttons function quickly and smoothly. The cables for the manual transmission wear over time, but replacing them is not an expensive job. Aftermarket quick shift mechanisms can put excessive strain on the cables, which you'll feel as a notchy shift action. A software update in October 2001 improved the throttle pedal action of early 996 Turbo models, so look for a stamp in the service book to show this work has been carried out.
The viscous coupling that apportions power between the front and rear axles is reliable and very unlikely to cause problems. In normal driving, it sends only 5 per cent of the engine's power to the front wheels, but this can increase to as much as 40 per cent in more extreme conditions such as snow or track driving.
Much more of a concern are the radiators and condenser for the air conditioning mounted at the front of the car. They are easily damaged and become clogged with leaves, which causes them to corrode. It's a well documented problem with all 996 models, so you should factor it in as routine maintenance to replace at least one of them every four years for a car that gets regular use.
Owner's view
"I personally prefer specialists with this age of car, because they will have seen more of them as they get older and will have experienced similar 'issues' when they do come up - this means less workshop investigation time required to fix them."
Andrew Howard
