I have a 2004 Ford Explorer XLT with 120000 miles. It runs good but the engine knocks somett. I keep the maintenance up to date on it.
The V6 2003 explorer has two cam chains, one on the back and one on the front, each driving one side. The 2004 may be the same engine. The guides often wear out and the chain makes a slapping noise which sometimes sounds like a knock. If it is the rear chain, the engine has to come out of the vehicle to replace the teflon guides. Special tools made for the expressed purpose are required. Cost with labor, probably around 1500 bucks.
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