07-27-2011, 08:38 PM
Join Date: Feb 2004
Location: Knoxville, TN
Jump over to the Explorer forum(the big one) and hunt "SOHC tensioners cassettes".
The external tensioners have a lifespan of about 75k miles, they have a mechanical spring in them which wears out. That's almost always the first symptom you hear, but it's not the worst danger.
Inside the engine, at the end of each head(one in front, one in back), the cam chains leading to the center jackshaft, both ride on a plastic cassette. That plastic from the 1997 first SOHC, to the 2001 SOHC, all are a lower quality plastic which will fail eventually. When those wear or break apart, the chain gets way too loose, and the engine is killed. At that point your choice will be a new engine or a rebuilt engine.
Your local dealer likely quoted you the cost to change the external tensioners, which cost about $45 and $25. The front one can take an hour or two to change, the back one is about ten minutes to do. Find any decent mechanic to do those.
The internal chain cassettes are about $60 or so each to buy. The back one rarely fails evidently, so people avoid messing with that unless there is a symptom. It requires pulling the engine or trans out, it's between them.
There are a few parts wise to also replace if you get into the front to do that cassette, maybe $100 total more. The special tool to time the chains is a kit that runs about $150. That's a good sized job for a good mechanic, about five hours at least to R&R the whole front of the engine parts. There are a few things along the way which can slow things down.
It's best to plan to get the front cassette and tensioners done at the first 75k mile mark for pre 2002 SOHC 4.0 Ford engines.
98 Mountaineer 18's Zexel-Torsen diff, suspension work,12.75" x 1.25" rotors etc.
, 347 4WD soon.
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