The all-aluminium 3.0-litre engine used in the 968 is derived from that in the 944 S2. It has a bore of 104mm and a stroke of 88mm, with an 11.0:1 compression ratio. Lighter pistons and con-rods, along with VarioCam valve timing and Motronic engine management, produced 240hp at 6,200rpm. There's also a useful 225lb ft of torque at 4,100rpm.
This 16-valve, water-cooled engine is generally very reliable and robust. That can lead to neglect from previous, less fastidious owners, so it pays to check the motor and its service history very carefully. It doesn't suffer the same problems as the 944 with its rubber-toothed timing belt. However, the belt that drives the exhaust camshaft can stretch beyond the ability of the tensioner to take up the slack. If it breaks or jumps a tooth, it can cause the valves to hit the pistons and repairing the engine will be very expensive.
To avoid this, specialists recommend changing the belts, tensioners and cam chains every four years or 40,000 miles. That's sooner that Porsche advised in period, but it's worth it for the peace of mind with an older car. It's also worth replacing the rubber belt that drives the engine's twin balancer shafts at the same time. If you do all of this work in one job the bill will be around £1,000, but gives you four years of worry-free driving.
As for the manual and automatic gearboxes, they are both strong and should not be a cause for concern. Make sure both shift cleanly between the ratios. Some owners think the manual is super slick while others regard the shift as quite heavy. This is down to personal preference, but there should be no noises or reluctance from the 'box. The 968 uses an LUK dual-mass flywheel, but it's not a worry, unlike the Freudenburg one used in early 964s.
One noise you may hear on higher mileage cars is a turbine-like whirr as the car accelerates. This is the rear diff pinion bearing wearing out. To fix this needs either a new diff or the existing one to be completely rebuilt. A specialist will charge around £2,000 for a drive-in, drive-out replacement. A limited-slip differential was an optional extra when the 968 was new and desirable to have now.
Other faults to look out for include ensuring the electric radiator fan switches off with the ignition so it doesn't drain the battery. Check the clutch master cylinder isn't leaking and, when starting the engine, feel for any vibration from the engine or during the test drive. If there is, it's most likely a worn engine mount that has broken up due to heat from the motor.
PHer's view:
"I do my own servicing normally and the clutch change is the easiest and quickest I've ever done."
Anthony Smith