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Porsche 928 Problems & Known Issues

The most common Porsche 928 problems ranked by severity — what to watch for, what it costs to fix, and what happens if you ignore it.

Generations

928 — Porsche 928
1987–1995
5.0L V8

Top issues to watch for

The most serious Porsche 928 problems ranked by severity. We track 5 known issues — here are the ones you need to know about first.

Dangerous
Brake hose corrosion and ferrule failure (928)
9281987–1995100k–200k miles
MOT data shows 928s fail brake hose ferrule corrosion tests at 4.9 times the national average. The ferrules (metal crimped ends of flexible brake hoses) corrode due to the car's age and exposure to road salt. When ferrules fail, brake fluid pressure is lost and the brakes become ineffective. This is a critical safety issue.
What happens if ignoredFailed brake hoses can cause complete brake failure resulting in serious accident. The car should not be driven if brake hose integrity is compromised. Replacement requires specialist brake system knowledge and proper bleeding procedures.
Independent garage
£150–£300
Specialist
£200–£400
Main dealer
£300–£500
Parts only
£40–£80
Dangerous
Timing belt failure and valve damage (928)
9281987–199560k–120k miles
The 928 uses an interference V8 engine where timing belt failure causes catastrophic valve and piston damage. The rubber timing belt deteriorates with age and mileage, and failure without warning is documented across all 928 variants. Due to the car's age, many have exceeded recommended replacement intervals multiple times.
What happens if ignoredTiming belt failure destroys the engine requiring complete rebuild or replacement. Repair costs typically exceed the car's value. The 928's complex V8 design makes timing belt work expensive even as preventive maintenance.
Independent garage
£800–£1,200
Specialist
£1,200–£1,800
Main dealer
£1,800–£2,500
Parts only
£200–£400
Major
Wheel bearing failure at high mileage (928)
9281987–1995100k–200k miles
MOT data shows 928s fail wheel bearing tests at 9 times the national fleet average, particularly on high-mileage cars. The combination of the car's weight, age, and performance driving history puts exceptional stress on the bearings. Failure typically occurs on the rear axle first due to the transaxle configuration placing more weight over the rear wheels.
What happens if ignoredA failed wheel bearing can cause wheel collapse and complete loss of control. Replacement requires specialist tools and knowledge of the transaxle configuration. Costs are high due to the complexity of accessing rear bearings.
Independent garage
£400–£600
Specialist
£600–£900
Main dealer
£900–£1,400
Parts only
£150–£300
Major
Excessive fluid leaks from engine and transmission (928)
9281987–199580k–200k miles
MOT data shows 928s fail environmental fluid leak tests at 8 times the national average. The V8 engine and automatic transmission develop multiple leak points as seals age. Common sources include the rear main seal, transmission oil cooler lines, and automatic transmission case. These cars were designed when oil consumption and minor leaks were considered normal.
What happens if ignoredExcessive leaks can pose environmental hazards and safety risks to other drivers. Major leaks can lead to low fluid levels causing engine or transmission damage. The 928's complex layout makes leak diagnosis and repair time-consuming and expensive.
Independent garage
£300–£800
Specialist
£600–£1,200
Main dealer
£1,000–£2,000
Parts only
£50–£200

1 more known issues tracked

Including wear items, electrical niggles, and generation-specific problems.

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Related

Porsche 928 reliability FAQs

What are the most common problems with the Porsche 928?

The Porsche 928 has 5 known issues across 3 severity levels. The most serious are: Brake hose corrosion and ferrule failure (928), Timing belt failure and valve damage (928).

Is the Porsche 928 reliable?

The Porsche 928 has 2 dangerous and 2 major known issues. Most can be avoided with a thorough pre-purchase check and full service history.

How much does it cost to fix Porsche 928 problems?

Repair costs range widely. The most significant issue (Brake hose corrosion and ferrule failure (928)) costs £150–£300 at an independent garage. Minor issues can be under £200. Always get a full inspection before buying.