had the engine oil seal replaced last year the one behind the fly wheel pulley.first noticed spots of oil in a line around the engine compartment bay. volspec looked at it and said the fan belt was to tight and had damaged the oil seal.as it was volspec that had serviced the engine from new had they left the fan belt to tight.had to pay anyway if you have spots of oil in a line around the bay its the oil seal and how tight is tight if volspec cant get it right how are we supposed to know.
BEWARE THE SMILING MAN WITH MARINE ENGINEER ON HIS OVERALLS 😆
As a diesel engineer I can say it is very important that engines are run up to temperature regularly or they will dry out the oil and water seals and leak. A 37 recently sold with very low engine hours has had oil seal problems. I would be suspicious of any diesel engine that has not done 100 hours per season. Its just like a car, they need to be used.
This advise is also relevant when laid up and out of the water over a winter. I run the engine from a bucket of water with a hose in it every 6 weeks until warm. New engine oil before layup is essential also.