Not sure, but what I do know is that there was a recall if the car was under warranty and the owner decided to do it. Possibly try to bribe the dealer into letting you know if there is any history for the car. They usually don't do this I hear, but if you go in person and ask really nice you might get lucky.

Remember to do the valve stem seals it requires removal of cam and rockers. If yours does not show any oil on the spark plugs, it is 99.9% chance it has already been removed to do the stem seals. At 155k there is no chance they are original if you have no oil consumption on the plugs.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k