Rickster70

I noticed recently that my 1999 Cherokee Sport 4.0L with 205,000 miles has been getting noisier on start up. The lifters tick/tap until it warms up and then it quiets down. I started reading up on the subject on various sites to see if I should do anything about it. Opinions vary widely on oils, ZDDP levels and additives. I came to the conclusion that I should switch from the Castrol GTX High Mileage I've been using since around 80,000 miles to Mobile1 High Mileage 10W-30, also changing to the recommended Mobile1 brand filter. I have always used 10W-30 in the summer and 5W-30 in the winter per the owners manual, I live in Michigan.

The noise is not any better and may even be a bit louder, but still quiets down after it warms up. After doing more reading, I'm now worried that switching to the Mobile1 full synthetic will cause more harm than good. It has only been about 200 miles since the change. Now I'm wondering if I should stay the course or switch it out immediately.

Thank you

tech

You can try a lifter clean additive , it sound like they are getting a little gummed up . Lifters don't go bad all at the same time .
Let us know how it goes .

EZEARL

You need to verify your oil pressure. I believe Harbor Freight sells a kit that mounts where your oil pressure sending unit is.

If it checks out good add a quart of Marvel Mystery Oil in place of one quart of what ever oil you choose. But it sounds to me you keep your oil and filter changed regularly so I can't see sludge being a problem although other things can cause it.

NM-XJ

I'm going to play devils advocate and suggest that you don't have a serious problem. That being said, I haven't heard it so maybe you do.

The 4.0's are noisy engines - I've had lifter tick since Day 1 ....that was nearly 19 years ago. I have one lifter that makes a lot of noise for a few moments on really cold mornings. You've got 205k on the clock...might be a little noisier than when it was younger. Keep high quality oil in it, Mobile1 or - Rotella, Rotella, Rotella - and keep rollin'!

I noticed a little more lifter tick after converting from Pennzoil to Rotella. No issues 8k miles later.

Cummins93

You could consider a block heater. I enjoy mine greatly in the winter.

Ralph77

I have what I believe to be a similar issue developing. '00 with about 160K. Only during a cold start up. Starts about 1 minute after you start her. Goes away in about 5 minutes. Have to make sure it is actually a lifter tick and not some sort of exhaust leak. Haven't gotten to checking yet. Run conventional 10/30W in the warmer months and 5/30W in the colder ones. With a 1085 Napa Gold, rebranded Wix, filter. Thinking about putting in 16 to 32 ounces of Marvel Mystery Oil when I swap out the oil in the next couple weeks or so. See what happens.

s346k

the valvetrain will be *extra noisy for about 1k miles after an oil change. especially with synthetic oil.

Waynerd

I used Castrol high mileage in the wj I had with 165k. I wasn't happy with the way it sounded. I switched to conventional and it was much better.

Ran a half quart of mystery oil in my 213+k mile 98 4.0 recently. I changed that oil ASAP because it was super noisy.

Currently I have 4 running Jeeps. 2 98's a 2001 and a 99. I was running Rotella T4 10-30. Then I made the switch to T5 10-30. My motors are very quiet until after a few thousand miles. I can pretty much judge by the sound when it's time to change the oil. I did notice with the T5 that it takes a bit longer for the oil to break down but I did get a bit more seeping from the old gaskets.

Recently Walmart has not been stocking enough T5 so the last oil change I used conventional Quaker state. I only chose it because the price was about the same as Rotella. I'm happy with the results but I will be switching back to the T5 from now on.

Also running Napa gold or Wix depending on where I get the filter.

Waynerd

Forgot to add. The 99 has about 100k, one 98 has 163k one has 213k and the 01 has 208k. All 4.0

Ralph77

Now this as me rethinking what I am going to do if and when I determine for sure that it is a lifter tick. Which I am pretty sure it is. I don't drive much. Live a 1/2 mile from work and don't have a life, LOL, so I change my oil in April and October. Maybe 2500 miles on the oil change when I do. Also wondering if my lack of driving it has helped this come about. I do try to take it on a good blast on the highway from time to time. And actually go out of my way in the morning when going to work. I have this little route. When I am pulling in the parking lot at work the thermostat is just opening and the temp drops from 210 to 195.

Tbone289

Pull the valve cover. Use a spray bottle and squirt MMO (Marvel Mystery Oil) down the pushrod holes to soak the hyraulic lash adjusters ("lifters") really well. Put the valve cover back on, but let the MMO soak overnight. When you start it in the morning, your sticky HLAs will be quiet.

I did this about 3000 miles ago, and mine have remained quiet since. They had been clattering loudly for at least 20,000 miles prior to the soak. This works much better than adding MMO to the oil, because you are using it full strength right where you need it. I only used about 8 oz.

Ralph77

Any reason to replace the Felpro gasket that I put on about 3 years ago? '00 XJ by the way.

Tbone289

If it's one of the blue felpro gaskets, I doubt you'll have to replace it.

The HLAs don't like short trips and constant low RPMs. I've noticed mine are quieter if I run if I run it up through the RPMs and "exercise" them a little bit. Taking them out for a "blast" as you mentioned is a good thing.

Ralph77

It is a blue one. Yeah do what I can to drive it. Just last week I went to gas up. Where I live driving a 1/2 hour can save you up to 35 cents a gallon. So I figure if I am going to waste gas to drive it more then I do I should go buy cheaper gas when doing it. 20K before you did the Marvel treatment huh? Might wait till next year. Really trying to finish working on the Jeep for the season. I'm tired. Which really just means October maintenance. Wash, compound, and wax. Clean and detail the interior. Oil change, lube, and top off any other fluids if necessary. Very liberal application of Fluid Film.

97grand4.0

Doing my timing chain as we speak, ..found the plastic tensioner piece in 2 pieces flopping around and a ton of slack...same symptoms as yours...
this from the FSM: the correct timing chain has 48 pins. A chain with more than 48 pins will cause excessive slack." SO the chain in there NOW has 64 pins, the diagram in the FSM shows 48 pins, and my NEW uninstalled napa chain has 64 pins. Thinking the OE mopar chain has 48 pins and Im marooned. Thinking the guy who changed this last time made this mistake.

Update. Chain helped, but the tick you described is exactly what I have, sort of a multi lifter chatter. On cold start, quiet for about a minute, then loud chattering for about 3 mins. Then quiets down again until I park for a few mins. Thinking maybe exhaust? or sticky lifters, but with 203 on the clock, they seen better days.
Also considering the MMO down the pushrod soak described above.

Im looking to do the back fed ShopVac trick with the exhaust to check for leaks. Hear that works pretty good.