Skip to content
pcarbuddy
964 · 1994 HaloAir-cooledManual only

1994 Porsche Speedster

3.6 L flat 6 · RWD · Speedster · air-cooled

Power
247hp
Torque
228lb-ft
0–60
5.7s
Weight
3,020lb
lb / hp
12.2
Displacement
3.6L

Specification

US-market 1994
Power 247 hp
247 700
Weight 3,020 lb
2,910 3,640
Weight to power 12.2 lb/hp
4.6 lower is quicker 13.0

Where this car sits against every 911 in the catalog.

Engine
Engine code M64/01
Layout flat 6, air-cooled
Displacement 3.6 L
Aspiration Naturally aspirated
Power 247 hp @ 6,100 rpm
Torque 228 lb-ft @ 4,800 rpm
Redline 6,800 rpm
Specific output 69 hp / L
Chassis & body
Drivetrain Rear-wheel drive
Body styles Speedster
Transmissions 5-speed Manual
Curb weight 3,020 lb
Wheelbase 89.4 in
Length 168.3 in
Width 65.0 in
Height 50.6 in
Performance & market
0–60 mph 5.7 s
Top speed 159 mph
Weight to power 12.2 lb / hp
MSRP when new $66,000 base
Production 936 built

About the 1994 Speedster

1994Speedster built in a run of roughly 930. Final 964 model year before the 993.

SpeedsterChopped windscreen, manual top and a double-bubble tonneau on the narrow body. Around 930 built worldwide and comfortably the rarest US 964.

Known issues

6 Specific to the Speedster

Distributor drive belt failure

Critical $300–$900
Affects

Naturally aspirated 964 with the twin-distributor ignition. This is the failure the generation is known for.

What happens

The M64 runs two distributors, the second driven from the first by a small toothed rubber belt hidden inside the distributor housing. Ozone from the ignition attacks the belt, it snaps without warning, and the second bank of plugs stops firing. Beyond the immediate misfire, the resulting timing mismatch can do serious damage. Porsche later issued a vented cap to let the ozone escape.

Symptoms
  • Sudden severe misfire and loss of power
  • Running on what feels like half the engine
  • No warning whatsoever beforehand — the belt is not visible without opening the housing
What to do

Replace the belt on a schedule regardless of appearance, and fit the updated vented cap if the car does not already have it. Ask specifically whether this has been done and when — "it runs fine" is not an answer, because it always runs fine until it does not.

Parts for this job

Engine oil leaks

Critical $500–$12,000
Affects

All 964, and worst on the earliest cars.

What happens

The 964 leaks in ways other air-cooled 911s do not. Beyond the usual valve covers and return tubes, the early engines suffer at the cylinder head and case sealing surfaces, and putting that right properly means the engine out and apart. Porsche revised the sealing during the run, so later cars are better but not immune.

Symptoms
  • Persistent drips despite gaskets having been replaced
  • Oil soaking the engine tinware and heat exchangers
  • Burning smell after every drive
  • A seller describing it as "normal for an air-cooled car"
What to do

Establish the source before accepting any reassurance. Valve covers are routine; head and case sealing is an engine-out job that can approach the value of a cheaper 964. This single issue is the difference between a good car and a money pit.

Parts for this job

Dual-mass flywheel failure

Major $1,800–$4,000
Affects

All 964, early cars especially.

What happens

The dual-mass flywheel wears and its damping springs break down, producing rattle and eventually clutch problems. The original units were not durable and many cars have already been converted.

Symptoms
  • Rattle at idle that quietens when the clutch is depressed
  • Vibration through the pedal
  • Gear selection becoming notchy
What to do

Replace with the clutch, since the labour is shared. Many owners fit a single-mass conversion, which is more durable and noisier — a trade most 964 owners consider worthwhile.

Parts for this job

Valve guide wear

Major $8,000–$16,000
Affects

All 964.

What happens

Guides wear and let oil into the combustion chamber. It develops slowly and ends in a top-end rebuild.

Symptoms
  • Blue smoke on cold start or after a long overrun
  • Oil consumption with no matching external leak
  • Uneven leak-down figures across cylinders
What to do

No preventive fix. Insist on a leak-down test at inspection and treat a top end as a long-term budget item rather than a surprise.

Weak air conditioning

Minor $800–$3,000
Affects

All 964.

What happens

Marginal when new, and thirty-plus years of condenser corrosion and leaks have not helped.

Symptoms
  • Cooling only at speed
  • Nothing at idle in traffic
  • Repeated recharging
What to do

Uprated condensers and fans help. Expect improvement, not modern performance.

Parts for this job

Sunroof and electrical faults

Minor $200–$2,000
Affects

All 964.

What happens

The 964 added considerably more electrical complexity than the cars before it, and age tells: sunroof motors and cables, window regulators, the spoiler mechanism and central locking are all common complaints.

Symptoms
  • Sunroof binding or refusing to move
  • Rear spoiler not deploying at speed
  • Intermittent window or locking faults
What to do

Mostly individually cheap, collectively tedious. Operate every single electrical item during inspection — this is where deferred maintenance accumulates quietly.

Service intervals

9
Item Interval
Engine oil and filter 5,000 mi or annually
Distributor drive belt and vented cap Replace on schedule, not on condition
Valve adjustment 15,000 mi
Spark plugs 30,000 mi
Brake fluid 2 years
Fuel filter 30,000 mi
Transmission and differential fluid 40,000 mi
Clutch and dual-mass flywheel 60,000–100,000 mi
Valve cover gaskets As leaks appear

What fits this car

32 Sizes, capacities and part specs

The answers you need when something has already failed — bulb sizes by position, wiper lengths, battery group, fluid specs and capacities. Sizes are for US-spec cars and are a starting point: options and mid-year changes move them, so check against your own car and its VIN before ordering.

Bulbs

8 US cars use the upright round headlamp with a replaceable H4 capsule.
Headlight — low and high H4 60/55W One capsule serves both filaments. Shop →
Front turn signal PY21W Amber. Shop →
Front position / parking W5W Shop →
Fog light H3 55W Shop →
Brake / tail P21/5W Shop →
Rear turn signal PY21W Shop →
Reverse P21W Shop →
Licence plate W5W Shop →

Wiper blades

2
Driver side 20 in Shop →
Passenger side 20 in Shop →

Battery

3
Group size Group 48 (H6) Shop →
Location Front luggage compartment, right side —
Minimum cold cranking amps 600 CCA —

Fluids and capacities

7 No coolant. The oil does the cooling as well as the lubricating, which is why there is so much of it.
Engine oil — capacity 12.7 qt with filter Dry-sump system with a separate tank. Check warm and running, per the factory procedure. —
Engine oil — specification 20W-50 or 5W-50, high-zinc Formulated for air-cooled flat-sixes. Not the place for a modern low-zinc oil. Shop →
Coolant None — air-cooled No radiators, no expansion tank, no coolant service. —
Brake fluid DOT 4 Shop →
Transmission — manual 75W-90 GL-5 Shop →
Power steering Pentosin CHF 11S Shop →
Fuel tank 20.3 gal —

Ignition

3 The twin-plug engine needs twice the plugs, and the distributor belt is the highest-consequence cheap part on the car.
Spark plugs — quantity 12 Two per cylinder on the naturally aspirated cars. —
Distributor drive belt Replace on schedule, not on condition Hidden inside the housing. It gives no warning and its failure can take the engine. —
Distributor cap — updated Vented type The vented cap lets ignition ozone escape rather than attacking the belt. Fit it if the car does not have it. Shop →

Wheels and tyres

7
Bolt pattern 5 x 130 mm
Centre bore 71.6 mm
Lug bolt thread M14 x 1.5
Tyre size — 16 in front 205/55 ZR16
Tyre size — 16 in rear 225/50 ZR16
Tyre size — 17 in front 205/50 ZR17
Tyre size — 17 in rear 255/40 ZR17

Torque values

2 Safety-relevant. Verify against factory documentation before relying on these.
Wheel lug bolts 96 lb-ft (130 Nm) Star pattern, on the ground, calibrated wrench.
Engine oil drain plug 37 lb-ft (50 Nm) New sealing washer every time.

Fitment for the 1994 964 Speedster. Torque values in particular are safety-relevant — verify against factory documentation rather than relying on this page alone.

Buying guide

7
  1. 01

    Ask about the distributor belt first

    Before mileage, before colour, before anything. When was the belt replaced, and does the car have the vented cap? This part gives no warning and its failure can take the engine with it. A vague answer is a real signal about how the car has been kept.

  2. 02

    Take the leak story seriously

    Every air-cooled 911 seeps. The 964 has failure modes that require the engine out to fix properly, and "they all do that" is how those cars get sold. Get it on a lift and establish the actual source before you agree a price.

  3. 03

    Leak-down test across all six

    Valve guide wear is developing on most of these by now. A leak-down test is how you find out whether you are buying a top end with a car attached.

  4. 04

    Operate every electrical item

    Sunroof, spoiler, windows, locks, air conditioning, lights. Individually cheap, collectively expensive, and this is exactly where deferred maintenance hides on a 964.

  5. 05

    Later is better

    Porsche revised the engine sealing and other details through the run. All else equal, a 1993 or 1994 car is a meaningfully lower-risk purchase than a 1990.

  6. 06

    C2 over C4 unless you need the traction

    The C2 is lighter, simpler, more engaging and cheaper to maintain. The all-wheel-drive system adds complexity that thirty years has not made easier to service.

  7. 07

    Buy the sorted one

    The gap between a 964 that has had its engine addressed and one that has not is larger than the price difference between them. Paying more for documented work is almost always the cheaper route.

Parts and gear

14 Chosen for this car, not for the commission

What a Speedster actually costs to keep, grouped by why you would buy it. Prices are typical US parts-only figures — labour is separate, and the DIY note says whether that matters. Where a link earns us a commission it costs you nothing and never changes what appears here.

Parts that fix a known problem on this car

4 Each one maps to an issue above
  • Ignition $120–$400

    Distributor drive belt and vented cap kit

    The highest-consequence cheap part on any air-cooled 911. The belt is hidden, gives no warning, and its failure can destroy the engine; the vented cap addresses the ozone that attacks it. If you buy one thing on this page, buy this.

    FCP Euro → DIY or shop
  • Engine $80–$320

    Valve cover gasket set

    The accessible end of the 964 leak problem. Worth doing early so that any remaining leak is genuinely diagnostic rather than lost in the noise.

    FCP Euro → DIY or shop
  • Drivetrain $1,200–$2,800

    Clutch and single-mass flywheel conversion

    The common answer to a failed dual-mass unit: more durable, audibly noisier at idle, and a trade most 964 owners make happily. Do it with the clutch or pay the labour twice.

    FCP Euro → Shop job
  • Cooling $700–$2,500

    Uprated A/C condenser and fan kit

    The established fix for a system that was never good. Buys usable air conditioning, not modern air conditioning.

    FCP Euro → Shop job

Worth doing before it fails

2 Cheaper than the repair it avoids
  • Engine $25–$60

    Magnetic drain plug

    Early warning at every oil change on an engine whose rebuild runs to five figures.

    Shop this → DIY
  • Ignition $200–$600

    Twin-plug ignition service set

    Twelve plugs, caps and rotors. A full refresh transforms starting and idle quality on cars where owners have quietly accepted degraded ignition as character.

    Shop this → DIY

Consumables you will rebuy

4 Ordinary running costs
  • Fluids $80–$170

    Air-cooled specification engine oil

    Heavier weight and a high-zinc additive package suited to this era of hardware. Around nine to ten quarts a change, and the wrong modern oil is a false economy on an engine like this.

    Shop this → DIY
  • Fluids $20–$60

    Oil filter and sump hardware

    Bought with every change, and worth cutting open every time on this engine.

    Shop this → DIY
  • Fluids $15–$60

    Brake fluid

    Two-year replacement. The cheapest safety-relevant service the car has.

    Shop this → DIY
  • Service $40–$130

    Air and fuel filters

    Routine owner jobs on this generation, and both are heavily marked up when a shop does them.

    Shop this → DIY

Tools worth owning

4 Bought once, used for years
  • Inspection $60–$250

    Leak-down tester

    Finds valve guide wear before you own it. If you are shopping several 964s it pays for itself on the first car you walk away from.

    Shop this → DIY
  • Inspection $30–$80

    Oil filter cutter

    Cheap insight into an engine that is expensive to open.

    Shop this → DIY
  • Lifting $150–$400

    Low-profile jack and jack pads

    You will be under this car looking for the source of a leak more than you expect. Do it safely and without crushing the jack points.

    Shop this → DIY
  • Storage $100–$500

    Battery tender and car cover

    These sit more than they run, and a 964 with damp and a flat battery finds new electrical faults to show you.

    Shop this → DIY