Q: Ive got a 2003 Jeep GC Laredo with the 4.0. For the last year or so a slight ticking from the lifters has grown to the point where I'm concerned about it. it used to be that it would tick when it was cold then go away as it warmed up now it just ticks all the time at a low rpm. ive heard this is quite common and was wondering if there were any easier fixes.
A: If the MMO doesn't clean up the lifter tick, you may try using a slightly heavier weight oil. I would avoid any additives, like Lucas, as they will thicken it too much and actually make the problem worse. 4.0 lifters have a really small oil feed hole, sludgy or hi viscosity oil just won't get in and pump them up very well. It takes the right balance of thin enough viscosity and thick enough to not bleed out too fast. Bumping your oil weight up by 5w, say from a 5w-20 to a 10w-30 often helps without completely blowing your long term mileage ( like any Jeep has good mileage.)