2000 Taurus Engine Noise problem

3.0L Vulcan motor - 110,000 km (66k miles) auto trans

Once the engine is warm there is an intermittant sound like marbles in a jar from under the hood. Sometimes it is very short with large gaps inbetween events and other times it is almost constant. It was quite noticable on a recent highway trip in high wind. I cannot make the noise happen; it is constantly intermittant (if there is such a thing

) when the motor is hot. I noticed that I seem to have used a bit of oil too (not excessive but down a bit).

Any ideas?

PS I recently switched to Castrol's semi synthetic oil for high mileage cars. Did the noise start soon after changing to semi-synthetic?

66k miles really isn't that high mileage, to be honest. I hate to preach about what people should use in their cars; but synthetic oil used in an engine that's used to conventional oil (and running well on conventional oil) is a risk.

Synthetic oil will leak through smaller openings (hence your engine is using more oil than it used to). It will loosen up potential gunk inside the engine, especially on engines with truly high miles or an oil-change neglected engine.

I suggest switching back to conventional oil on the next oil change. If it helps, then you've saved money and fixed the problem.

Synthetic oil, IMO, isn't worth the extra money unless you use it right after the motor is broken in.... so the motor can last 5 times as long as the car instead of the 3 times you'd get from conventional oil with regular changes.

My guess for the marble-rattle sound… the synthetic oil in the blend is too thin causing an oil pressure problem (isn’t synthetic zero-weight?). The extra noise from the windy trip is likely a result of the engine working harder to fight against the wind.