Porsche 928 Buyer's Guide

Written by Zach, an independent mechanic in the Pacific Northwest. Last reviewed September 2026. Spot a mistake? Tell me.

Overview

The 928 was supposed to replace the 911. It didn't, and it's better for being its own thing: a front-engined V8 grand tourer built to cross continents quickly and in comfort. It's also one of the most complex cars Porsche has built, and deferred maintenance compounds fast. The timing belt runs an interference engine, the wiring harness is getting old, and the vacuum system has a hundred ways to leak. Buy the best one you can afford. A cheap 928 is the most expensive 928.

Production: 1978–1995
Built: ~61,000 worldwide
Price range: $15,000–$150,000+
Best years: 1990–1995 GTS (most powerful, best refined)

What to Pay

Prices checked January 2026. Rough US market ranges. Location, history, and options move these a lot.

Project

$8,000–$20,000

Non-running or cars with unknown timing belt history. 928 projects can become money pits.

Driver

$20,000–$45,000

Running and driving S4 or GT examples with some needs. Budget for maintenance.

Excellent

$45,000–$80,000

Well-maintained GTS or pristine S4/GT with full service documentation.

Concours

$80,000–$175,000+

Low-mileage GTS manual or exceptional early cars. Prices continue rising.

Which One to Buy

928 / 928S

1978–1986

The early cars: a 4.5L V8 with 219 hp in US trim, then the 4.7L 928S. US 928S models from 1985–86 got a 5.0L 32-valve V8 with 288 hp. Good cars, just less refined than what came later.

Desirability Low

928 S4

1987–1991

The first big update: a 5.0L 32-valve V8 with 316 hp, plus a better interior. For most buyers, the best value in the range.

Desirability High

928 GT

1989–1991

A 326 hp S4 with a firmer suspension, sold only with a manual gearbox. Rarer than the S4.

Desirability High

928 GTS

1992–1995

The last and best 928: 5.4L, 345 hp, wider rear bodywork, and every running change Porsche made. Also the most expensive.

Desirability High

Walk Away If…

Unknown timing belt service history—budget for immediate replacement
Overheating issues or evidence of head gasket failure
Non-functional vacuum systems (door locks, HVAC not working)
Automatic transmission slipping or harsh shifting
Severe oil leaks from multiple locations
Rodent damage to the wiring
Cars that have sat for extended periods without maintenance

Pre-Purchase Inspection

What I'd check on any 928 before buying, with a rough cost if it's bad. Print it and take it with you.

Engine (check first) 5 checks

Timing Belt Service The 928 V8 uses a timing belt that must be replaced every 60,000 miles. Belt failure destroys the engine. If bad: $2,500–4,000 for service / Engine if it breaks
Water Pump Should be replaced with timing belt service. 928 water pumps are expensive. If bad: $600–1,000 for pump alone
Oil Leaks Check cam covers, timing cover, rear main seal, and oil cooler lines. V8 has many potential leak points. If bad: $500–2,000 depending on location
Coolant Crossover Pipes Coolant pipes under the intake manifold corrode and leak. Common failure point. If bad: $800–1,500
Head Gaskets Not common failures but serious when they occur. Check for coolant in oil. If bad: $3,000–6,000

Transmission & Drivetrain 4 checks

Automatic Transmission Most 928s are automatic. Check for smooth shifting and proper fluid condition. If bad: $3,000–6,000 for rebuild
Manual Transmission (GT) GT and some GTS models have 5-speed manual. Test all gears for smooth engagement. If bad: $2,000–4,000
Torque Tube The tube connecting engine to transaxle contains the driveshaft. Check for vibration. If bad: $1,000–2,500
CV Joints / Axles Rear CV joints wear over time. Listen for clicking in turns. If bad: $500–1,000

Suspension & Steering 3 checks

Weissach Rear Suspension The 928's sophisticated rear suspension has many bushings and links that wear. If bad: $1,000–2,500 for full rebuild
Power Steering System Check for leaks from pump, rack, and lines. The system operates at high pressure. If bad: $500–1,500
Front Control Arms Bushings and ball joints wear causing poor handling and tire wear. If bad: $600–1,200

Electrical & Systems 4 checks

Vacuum System The 928 uses vacuum for HVAC, door locks, and cruise control. Leaks cause multiple failures. If bad: $300–800
Climate Control HVAC system is complex with vacuum and electrical components. Test all functions. If bad: $500–2,000
Instrument Cluster Check for working gauges and proper speedometer/tachometer operation. If bad: $400–1,000
Power Seat Motors Electric seats can fail. Test all adjustments including memory function. If bad: $300–800

Body & Interior 3 checks

Rust Check rocker panels, door bottoms, and around sunroof if equipped. Later cars rust less. If bad: $1,000–5,000+
Leather Condition Interior leather can crack and wear. Check seats, door panels, and dashboard. If bad: $1,000–4,000
Headlight Covers Pop-up headlight covers can crack or discolor. Check operation and condition. If bad: $500–1,500

Worth Paying Extra For

Documented timing belt service within last 60,000 miles
A GTS if you want the fastest 928 and the one that holds its value best
Manual transmission (rare but most desirable)
Service records from Porsche specialists
Working air conditioning and climate control
Complete vacuum system operation
Rust-free body panels
Factory tool kit and books

Running Costs

Insurance: $800–1,500/year (classic car insurance available)
Annual maintenance: $2,000–4,000 for regular service
Common repairs: $1,000–3,000/year typical
Fuel economy: 16–22 MPG

Before You Buy

A 928 isn't cheap to run. Budget for proper maintenance before you buy.
Never skip or delay the timing belt service
The S4 is the best balance of performance and price.
GTS prices have climbed a long way. They're collector cars now.
Manual cars are rare and cost significantly more.
Find a specialist who knows 928s before you need one.
The 928 Owners Club is an excellent technical resource.
Parts are available, but they cost more than 944 parts.
A well-sorted 928 is one of the most capable grand tourers ever made.
They were over-engineered, and a well-maintained one can pass 300,000 miles.

Own a 928?

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