Milo, I seriously doubt the oil filter gets clogged even with 10k mile oil changes; however, you may get some sludge build-up in the top of the engine if you frequently make short trips that don't allow the engine to achieve full operating temperature. Is there an oily gunk on the underside of the oil fill cap? Even with the newer engines and synthetic oil I change oil and filter every 7,500 miles. It's very affordable preventive maintenance.

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Fred Hoelzle