Porsche 993: Buyers Guide

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Common Issues by Area & What to Check Before You Buy

The Porsche 993 is one of the most iconic 911s ever produced. As the last of the air-cooled models, it has become a highly desirable modern classic, with values reflecting that status. With base Carrera models now commanding strong money and rarer variants sitting far higher, buying the right car is critical.

All Porsche 993s are now used, ageing classics, and condition matters far more than mileage. This buyer’s guide breaks down the most common issues by area of the car, based on real-world inspection and maintenance experience at Sports Vehicle Performance, to help you avoid costly surprises.

Service History & Provenance

Before looking at the car itself, the service history is the most important factor.

• Full service history is essential

• Stamps alone are not enough — read invoices and advisories

• Look for evidence issues have been rectified properly

• Genuine or high-quality replacement parts are important

Mileage is far less important than how the car has been maintained. Low-mileage cars that have spent long periods parked can often be worse than higher-mileage, regularly used examples.

Bodywork, Corrosion & Exterior

The Porsche 993 uses galvanised steel, which offers good corrosion resistance, but age means rust is still a concern.

Windscreen Scuttle & Seals

• Check carefully around windscreen edges

• Pay particular attention to corners

• Trapped moisture causes blistering and corrosion

Repairs here can be expensive if left unchecked.

Headlight Bowls

• Remove headlights if possible

• Corrosion beneath the headlight units is common

• Often hidden until lights are removed

Wheel Arches & Inner Structures

• Inspect all wheel arches thoroughly

• Look for signs of previous repairs

• Check for filler or uneven underseal

With the age of these cars, accident repairs are not uncommon.

Rear Chassis Legs & Bumper Supports

• Rear bumper support brackets corrode

• Causes loose or poorly fitting bumpers

• Front bumper supports can suffer similarly

Door Check Straps

A well-known issue on 993s.

• Check straps corrode and pull out of the body

• More common on the driver’s side

• Repair is more involved than expected

This is not a simple bolt-on repair and should not be ignored.

Seals & Dirt Traps

• Dirt and moisture collect behind seals and covers

• Leads to hidden corrosion

• Particularly common around sill covers and lower body sections

Always inspect behind covers where possible.

Targa Roof (If Fitted)

• Age-related electrical issues are common

• Seals can shrink and leak

• Check full operation and water tightness

Roof repairs can be costly, so test thoroughly.

Engine & Engine Bay

The 993 engine is robust but has several known weaknesses.

Engine Lid Struts

• Very common failure

• Lid drops unexpectedly

• Cheap parts, easy fix, but a good indicator of general care

Oil Leaks (Very Common)

A known Achilles’ heel.

• Common leak points include:

  • Cam covers

  • Timing chain covers

• Oil often drips onto exhaust components

• Causes burning oil smell and visible smoke

Proper repairs often require engine removal, making this an expensive job.

Undertray & Heat Management

• Many owners remove the undertray

• Improves heat dissipation

• Believed to reduce exhaust valve guide wear

Presence or absence is not necessarily a problem — but understanding why it’s been removed is important.

Oil Level & Oil Usage

• Oil level must be checked at operating temperature

• Incorrect oil levels are common due to owner misunderstanding

• Running low on oil can cause serious damage

Always check oil level after a proper test drive.

Ignition System & Belts

Spark Plugs (Twin Plug Engines)

• Upper and lower plug rows

• Cylinder six is difficult to access

• Often skipped during DIY servicing

Check history confirms all plugs have been replaced.

Distributor Belt

• Twin distributor system uses a connecting belt

• Must be changed at correct intervals

• Failure can cause major issues

Neglect can result in seized distributors, sometimes requiring engine removal.

Auxiliary & Fan Belts

• Age causes cracking and loss of tension

• Failure can lead to secondary damage

Check condition and service records.

Brakes & ABS

Brake Discs & Pads

• Generally reliable

• Less servo assistance than modern cars

• More mechanical pedal feel

Check:

• Disc lips

• Pad material

• Corrosion on rarely-used cars

ABS System

• ABS sensors can fail with age

• Check for warning lights

• Ensure ABS activates correctly under braking

Cooling System

Heater Pipes

• Common age-related cracking

• Can fail suddenly and leak coolant

Oil Temperature

• Monitor oil temperature during test drive

• High readings may indicate:

  • Faulty cooling fans

  • Faulty temperature sensor

Tiptronic Cooling Lines (If Applicable)

• Lines to front cooler corrode

• Repairs are labour-intensive

• Braided line upgrades improve reliability

Suspension & Chassis

Suspension Bushes & Dampers

• Bushes typically last around 40,000 miles

• Many cars will have had suspension work by now

• Quality replacements (e.g. Bilstein) are a positive sign

Suspension investment usually reflects careful ownership.

Exhaust System

• Original 993 exhaust systems are relatively durable

• Far better corrosion resistance than later water-cooled cars

• Check brackets, fixings, and general condition

Aftermarket exhausts are common — ensure they meet emissions requirements.

Gearbox & Drivetrain

Manual Gearbox

• Generally very reliable

• Check clutch history

• Typical clutch lifespan around 70,000 miles

Tiptronic Gearbox

• Strong overall

• Main issues relate to:

  • Corroded cooling pipes

  • Sump leaks

Otherwise very dependable.

Interior & Electrical Systems

Electrical Components

• Age-related failures are common

• Check:

  • Windows

  • Air conditioning

  • Heaters

  • Gauges

  • Roof operation (if applicable)

Alarm Systems

• Original alarm systems were unreliable

• Many cars fitted with aftermarket alarms years ago

• These systems can now fail themselves

Check locking, unlocking, and alarm behaviour carefully. Low battery voltage can also cause false faults.

Final Buying Advice

The Porsche 993 is an incredibly rewarding car to own, but it must be bought carefully. Values mean mistakes can be expensive, and deferred maintenance adds up quickly.

Key points to remember:

• Buy on condition and history, not mileage

• Expect age-related issues

• Many problems are manageable if addressed early

• Specialist inspections are strongly recommended

Buy the right example, and the 993 remains one of the most engaging and characterful 911s ever made. Thinking of buying? We can help so be sure to get in touch! Info@sportsvehicleperformance.co.uk 01386 793138