4.0 V6 chain rattle - Percentage

[CDW6212R]

Just to clarify and to see if I understand correctly, the Fourth generation Explorer's do not have this timing chain issue correct? So they are not using the V6, 4.0 SOHC like previous years? If they are using the same engine what improvements did they make on the engine? Stronger plastic on the cassettes? Thanks!

All of the 4.0 SOHC engines have issues. The plastic might be slightly better in the latest parts revisions, but the inherent external tensioner problem still exists. The pressure those exert to keep the chains tight, is dependent on the strength of the spring inside. Those become weaker eventually. The rattle usually begins because one or both of the tensioner springs has weakened enough to let the chain(s) become loose. Unless they would redesign those tensioners to eliminate the springs, those are weak links. At this time, this age of those engines, Ford isn't going to do that.

 

[Tech By Trade]

Ford used the cologne platform since the 60's. The block is the same through all the displacements. The 4.0l OHV maxed the displacement, with no room for expansion with reliable cylinder walls. The sohc allowed for wall reliability with removal of the push rods and addition of the jack shaft but came with the problem of cassette failures.

 

[96eb96]

It is not only a Ford problem. Audi also places timing in the rear, maybe it is a German thing because these engines are German. They blame it on maintenance, who knows.

No More Audi 4.2 timing chain problem -Waltham's service

 

[Jason94sport]

Does a manual trans version make any difference? Are the chances for more mileage out of the engine before the guides or springs go less or the same as an auto? I'm looking at a 2002 2WD sport with 93K miles & a manual trans.

 

[imp]

Does a manual trans version make any difference? Are the chances for more mileage out of the engine before the guides or springs go less or the same as an auto? I'm looking at a 2002 2WD sport with 93K miles & a manual trans.

@Jason94sport
I think it unlikely that the transmission type affects the longevity of the chain guides very much. The 5-speed manual was pretty bullet-proof, if you don't mind the weakness built-into the throw-out bearing: it's mounted on a plastic collar. And, the "juice" type clutch release. I had a '99 with 4.0 OHV engine and manual, but 'twas a 2WD. Had a '96 before that, 4WD, much preferred in Missouri. Replaced the '99 with a 2004, 4.0 OHC, just turned 160K, no chain noise yet. imp

 

[bogart219]

All of the 4.0 SOHC engines have issues. The plastic might be slightly better in the latest parts revisions, but the inherent external tensioner problem still exists. The pressure those exert to keep the chains tight, is dependent on the strength of the spring inside. Those become weaker eventually. The rattle usually begins because one or both of the tensioner springs has weakened enough to let the chain(s) become loose. Unless they would redesign those tensioners to eliminate the springs, those are weak links. At this time, this age of those engines, Ford isn't going to do that.

Going by this if you would replace the Tensioners every 75K miles this engine would last a lot longer. If you keep the chains tight you should be alright, at least that is how I'm interpreting what you said, thanks!

 

[CDW6212R]

Going by this if you would replace the Tensioners every 75K miles this engine would last a lot longer. If you keep the chains tight you should be alright, at least that is how I'm interpreting what you said, thanks!

Remember that there are multiple tensioners. Nobody has really kept up with how changing just the external tensioners affect how long the plastic guides last. The oil and external tensioners are IMO the biggest factors, and gladly the easiest things an owner can handle.

I'll get a look at my front guide parts soon, which have right at 70k miles on them now, all OEM parts using synthetic oil always. My rear cassette is original, and I've owned the truck since it has 77,450 miles. I'm interested to see the rear guide plastic. If that looks fairly good, I'd be satisfied to say the back can last 150k miles with great oil and outside tensioner.