Oil passages run inside the bracket of the alternator, and the gasket of the bracket goes brittle from the heat of the engine and then cracks. From then on oil leaks out of it into the V valley of the engine.

The symptom is a visible trace of oil around the alternator, and this is the rarer case: here the leak also appears from outside, instead of only collecting in the V valley. Fresh, shiny oil around the alternator belongs here.

The gasket itself is under 10 dollars, but the labour is not. For the repair the alternator has to come off, the power steering pump has to be unbolted, the engine has to be lifted and the driver's side engine mount has to be removed as well. That is between 7 and 10 hours of work, with a bill of between 1000 and 1500 dollars, and workshops also allow for removing the intake manifold.

Because they are reached from the same place, the coolant pipe running in the V valley and the seals of the valley pan are usually done in the same job. If only one of them is on the invoice, it is worth asking why not the other two.