Porsche S
The M44.40 is the DOHC 16V head on the 2.5-litre block — a fundamentally different engine from the 8V base. 190 hp, more rev-happy, more refined. The 16V head brings its own weaknesses: twice as many valve guides, twice as many camshaft seals, more complex timing belt drive. Remains an interference engine — the timing belt is equally critical. Thermally more demanding than the 8V due to higher specific output. Find the S in good condition and you have the dynamically best 2.5-litre 944.
16V NA — the hidden gem of the range
The 944 S with 16-valve head is the 944 that connoisseurs buy: 190 hp from 2.5 litres, rev-happy to 6,800 rpm, DOHC head with significantly better gas flow than the 8-valve base. The transaxle layout provides neutral balance, the hydraulic steering unfiltered feedback. On an alpine mountain pass the 944 S is one of the most involving sports cars of the 1980s — regardless of price.
Engine Weaknesses 5
All M44 engines are interference engines. If the timing belt breaks, the valves bend immediately — typically 8 exhaust valves. No official Porsche replacement interval; generally recommended every 30,000–60,000 km. Timing belt history is a key purchase factor.
Symptoms: Engine stops abruptly, cranks unusually fast on restart attempt (no compression resistance), metallic knocking from the head
If the balance shaft belt breaks, it can wrap around the timing belt and take it with it — causing valve damage. Always replace together with the timing belt. Oil-contaminated belts wear faster.
Symptoms: Slapping noise from the belt drive, oil traces on the balance shaft belt, engine dies suddenly
A seized water pump can cause timing belt failure — catastrophic in an interference engine. The thermostat is positioned after the radiator (not before, as is usual), which makes diagnosis more difficult. Coolant in the oil points to a head gasket failure or the side-mounted oil cooler/heat exchanger on the block.
Symptoms: Temperature gauge rising unusually, coolant loss without visible leak, milky oil on the dipstick, squealing noise from the belt drive
All three front seals (crankshaft, camshaft, balance shaft) age together. Leaking oil contaminates the timing belt and massively accelerates its wear — that is the real risk. Replace all shaft seals at every timing belt change.
Symptoms: Oil drops under the belt cover, oil traces visible on the timing belt, oil smell when engine is warm
16 valves instead of 8 means twice as many guides that can wear. At high mileage (>150,000 km) oil consumption increases through worn guides. Replacing valve stem seals is labour-intensive due to the DOHC head — both camshafts must come out.
Symptoms: Bluish smoke on cold start, increasing oil consumption (>0.5 L/1,000 km), rough idle when warm
Vehicle Weaknesses 6
The 944 transaxle layout connects engine and gearbox via a torque tube — the bearings inside wear after 30–40 years. Removal is extremely labour-intensive as either the engine or gearbox must come out. Specialist refurbishment is cheaper than new OEM parts.
The 944 was fully galvanised from the factory but still rusts at weld seam edges. Sills rot from inside through the ventilation slots in the B-pillar area. Rear side panels rust when the tail light seals become brittle and water enters.
The rubber centre coupling between the engine and torque tube ages and starts rattling. Transaxle shaft bearings become noisy after 30–40 years. Clutch replacement is more involved than on conventional cars — the gearbox is at the rear.
Cold solder joints in the DME control unit, especially on early examples. Engine runs fine when warm, but cold it misfires sporadically or does not start. Resoldering by an electronics specialist is a cheap fix.
UV radiation and temperature cycling break down the dashboard material — cracked on almost every 944, especially the angular 944 I variant (1982–1985). Professional re-trimming costs €1,200–1,800. Used replacements are practically unavailable.
Most common cause: corroded 4-pin connector on the headlight motor (heat and vibration in the engine bay). Relays also fail. A manual emergency knob is on the motor. Always check connector and relay before replacing the motor.
Reports & Tests
19 owner complaints filed with NHTSA (1982–1991). Most reported: Fuel System (4), Gasoline (4), Fuel System (3).