The valve stem seals harden from the heat and the years, and from then on oil seeps through the valve guide into the combustion chamber. There are 32 such seals on the V8, and their material was a weak choice to begin with, because it goes brittle.

The characteristic sign is a puff of blue smoke, and not only at a cold start: it also comes when the car has idled for a long time at a light, or when it is started after standing for a while. Oil consumption rises slowly but steadily alongside it. The valve guide often wears together with the seal, so the repair does not necessarily end with replacing the seals. The fault appears above 130 000 kilometres.

The cylinder head does not have to come off for the repair. If the workshop has a valve spring compressor that can be used with the head in place, the camshaft and the chain do not have to be disturbed either, but the job is still a long one. The shop price is between 1800 and 3000 dollars, while the parts themselves are 300 to 500 dollars by comparison.