SOHC timing chain

[kh0432]

I see a lot of posts about timing chain problems with 4L SOHC motors. I have a 98 with 150,000 miles and it makes no noise. I am a stickler for replacing parts before they go bad. I've thought about replacing the tensioner and guide before they fail but I have one question. How many Explorers really have this problem? I've belonged to a lot of different automotive forums and have found that people generally post when they have a problem. You don't hear from people that are happy. Should I consider doing the repair before it's needed or wait until ther is an indication of a problem? Thanks, Keith

 

[koda2000]

I can't speak for everyone who owns a SOHC 4.0, but I can tell you that my SOHC has timing chain noise and has for almost 70K now. It seems to be a fairly common problem, but there are several contributing parts involved.

1. The guides tend to wear out
2. The hydraulic tensioner's springs tend to weaken with age
3. The materials used in the chain cassettes can break
4. Oil drains out of the hydraulic tensioners and you get noise at startup (00M12 kit)

From what I've read on this forum, it seems like at least 50% of people responding have one or more problems with timing chain noise and attempts at repairs are not always successful. As you've said, the people who don't have problems with their timing chains don't tend to post about it, so it's hard to say.

IMO, The timing chain design/materials used in the Gen II SOHC V6 engines were of poor design. I regret having ever bought mine (didn't know any better). Yet, some report going 200K+ without any noise.

If I were you, I'd keep doing whatever maintenance regiment you're doing and don't fix what ain't broke. Replacing timing chain components is a time consuming and labor intensive process (if your not doing the work yourself, it will exceed the value of your truck very quickly).