Valve Stem SealWe list this valve stem seal as an aftermarket replacement, a regular reach for parts buyers at dealerships stocking common engine wear items. It rides on the valve guide and stops oil from running down the valve stem into the combustion chamber, a common culprit behind blue exhaust smoke at startup. Keeping pieces like this in stock means a downed truck can get back to moving freight the same shift instead of waiting on a dealer order. Because the cross-reference for AC13207-2B500 is to an unrecognized supplier code, contact our team in Whittier with your truck make, model, and serial number to confirm fit before ordering.Aftermarket replacement part, cross-references original part number AC13207-2B500.Need help confirming fit? Call (562) 693-7748 with your serial number.Part number variants: AC13207-2B500, ac13207-2b500, AC132072B500, ac132072b500 ⚠ Warning: Some equipment has serial-number breaks that may not be reflected in the catalog. Contact us for clarification before ordering if uncertain.SCR Forklift Parts ships from Whittier, CA with next-day delivery available across the US when needed.