4. M60 V8 Nikasil Bore Wear (E34 530i, 540i)
Symptoms
Progressively worsening cold-start difficulty, rough idle when cold that smooths out as the engine warms, increasing oil consumption (more than 1L per 1,000 km), and eventually misfiring and low compression.
Cause
The M60 V8 used Nikasil (nickel-silicon carbide) cylinder bore coatings in early production. Nikasil is attacked by sulphuric acid, which forms when high-sulphur fuel burns and the resulting sulphur dioxide mixes with condensation in the cylinders. Australian fuel in the 1990s had relatively high sulphur content, and many Australian-delivered M60 engines have suffered bore wear as a result. The wear is irreversible, there is no gasket or seal that can fix it.
Fix
The only proper fix is a replacement engine block or resleeving with steel liners.
A replacement long block costs $5,000-10,000.
Resleeving is $3,000-6,000.
For most E34 530i/540i owners, the repair cost exceeds the car's value.
Before buying any M60-powered E34, a compression test and leak-down test are essential.
Compression should be above 10 bar on all cylinders with less than 1 bar variation between cylinders.
Any cylinder below 8 bar indicates bore wear.
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