I got a 91 Xj about a year ago and have really enjoyed the rig,but the valve tick is driving me crazy. I heard (read) that you may be able to unstick them buy squriting WD-40 or PB blaster on them and manually lossen them up?? Only 63,000 on the odometer, could I need to replace the lifters already?? Thanks

 

I can't imagine the lifters needing replacement with only 63K on them but for the past 20 years your Jeep has been owned by someone else. Maybe someone who only replaced the oil when they saw the paint blistering off the hood? Hard to say. I know a lot of people here swear by Sea Foam which is apparently something you run through the system to free up deposits but until I joined here, I'd never heard of it. Could also be a failing oil pump. You have many options. I wouldn't recommend the WD-40/PB Blaster route until someone confirms that it's a safe thing to do or that it will do any good.

My '89 has 107K on it and I've never heard anything from the lifters or valves... the suspension is a different story but I don't think Sea Foam will help with that :/

Good luck, hope you get it to quiet down.

 

It's been regularly maintained, with a stack of reciepts that came with it. It also has 40-60 pounds oil preasure, so I don't think it's the pump.I tried a quart of MMO in the last oil change.Have heard that Seafoam might help, but having never used it I am a little leary, but at this point I may give it a try.

 

Flat tappets tick.

Run Rotella T diesel oil and it will quiet them down a bit.

Also run a Wix filter it did a great job of quieting down my friends 98 Police.

I run rotella and wix and have no valve noise at 250k on my 98.

 

are you sure it's the lifters. could be the exhaust gasket. common problem on 4.0. and being a 91 probably has a cracked exhaust at the collector. the bolt next to the fire wall tends to break on exhaust manifold. Rislone is suppose to be the cure all for lifters. haven't tried it yet, but I have some to try on the next oil change.

 

I'm pretty sure the tick is coming from one of the rear rockers.I'm running a Mopar filter. I've heard Wix is good, but would it really make a difference? Whats the difference with the deisel oil?I know that I6's tick, but I've wrenched my whole life and just don't like the sound of this one. Thanks

 

The mopar filter is fine.

Diesel oil has more zinc. Our lifters were designed to run in higher zinc oil. The zddp level in new oils is lower than in the older oils. The diesel oil has levels much closer to the oil our engine was designed to run on.

Try it what do you have to lose $20 on an oil change?

 

Run it with Rotella and one quart of MMO. Change it in 1,000 miles and use the same combo. It's really helping on my 4.0. Also, when you start it and it ticks loudly, if that's the case, shut it off for 10 seconds and re-start. It should have primed the lifter.

 

What this guy said ^^

Plus it's a Jeep, almost ever Jeep I've seen with a straight six sounds like this. The tick wasn't to loud on my 94 and when I switched to Rotella it's almost nonexistent.

 

I think I'll try the seafoam and an oil change today. Thanks

 

I ran the Seafoam and changed the oils seems a little quieter,but still sounds like one lazy lifter. I'm pulling the valve cover today to investigate. Any ideas?