my 91 explorer has a wicked tick when it sits for a few days without being driven. it just turned 114k miles. i started it the other day and it had an extremely loud tick. sure sounds to me like a bad lifter. are these hydraulic lifters in these 4.0s? if so is there any type of fix to get them to quiet down? i dont really want to drive it like this. ive heard of additives like rislone that supposedly help quiet lifters, and a friend suggested putting a can of seafoam in there. just looking for some advice, or suggestions. if i do have to replace the lifters, how bad of a job is it to do? as always, thanks in advance!

 

Another place the "ticking" could be coming from is a rod bearing or a rod cap. However, usually it's something to do with a lifter is the culprit; ie, lifters, rocker arms, valve spring, cam shaft or a bent rocker rod. Just something to keep in mind when troubleshooting.

 

I forgot to say that investing in a engine stethoscope might help isolate the problem....good luck.

 

I'm having a similar problem with mine. I put Lucas oil in there and it did not help. But I also have not driven it but around the block twice because it also has other problems. When I drive it longer and if it quiets down I'll let you know!!

 

My 91 I fixed the tick with the Delta cams kit #F-40. IF you have the same problem I did:

Delta Camshaft (picture on lower right of page)

You will need an intake gasket set as well. The Delta Camshafts kit supposedly oils better than stock at the contact points. Not sure about that, but my tick is gone now...

Pull a valve cover and have a look...take the rocker assy off and see if you have galling/cupping on the rocker tips and or pushrod ends. Mine had 2 bad, and 1 on it's way. If it turns out to be lifters and not rockers/pushrods, you will need a head gasket set (heads have to come off to replace lifters) and fair warning: the lifters are pretty pricey.

Also recommend you do a search in the forum for "4.0 Tick" Plan on reading awhile.....