Porsche Turbo
The M44.51 is the turbocharged 8V block — 220 hp from 2.5 litres, KKK K26 turbo. The engine shares all timing belt weaknesses of the naturally aspirated version, but adds turbo-specific cooling concerns: the turbo run-on pump must continue running after shutdown, otherwise the oil cooks in the turbo bearing. The wastegate valve wears and can lead to uncontrolled boost. Still: a well-maintained 951 is mechanically robust and long-lived. 220 hp at 1,250 kg makes it the fastest 944 in daily use — the turbo lag below 3,000 rpm is part of the character.
The 951 — Porsche's forgotten hero
The 944 Turbo (internally the '951') is the Porsche the 911 crowd ignores — wrongly. 220 hp turbo four-cylinder, transaxle balance, no electronics to intervene. Below 3,000 rpm not much happens — then the KKK turbo builds boost and 330 Nm hit the rear wheels all at once. The turbo kick and the transaxle neutrality make it one of the most involving sports cars of the 1980s. Service history is everything.
Engine Weaknesses 7
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
The electric coolant pump should continue running for approximately 30 seconds after switching off, to cool the turbo bearings. If it fails, the oil in the bearing boils and the turbo is damaged. Check the pump and relay regularly — hold a hand on the turbo after switching off: it should feel warm, not hot.
Symptoms: No pump noise audible after switching off, turbo whine becomes louder/rougher, oil smoke when accelerating
The wastegate diaphragm ages and can tear — result: no more regulated boost pressure. Either boost failure (diaphragm torn, valve stays open) or dangerous boost creep (valve seat worn, no longer sealing properly). Both require immediate repair.
Symptoms: Boost pressure fluctuates uncontrollably, significant power loss, boost gauge shows overboost or no pressure
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
Oil accumulates in the intercooler via the crankcase breather. Efficiency drops, charge air temperature rises, power decreases. Regular cleaning (every 50,000–80,000 km) keeps the cooler effective.
Symptoms: Gradual power loss, higher intake air temperature, oil traces on charge air hoses
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).