CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Jeep 2004 Grand Cherokee ,lifters or exhaust manifold?

I have a 2004 Jeep Gran Cherokee, 87000 miles, 6. I have this sound,sounds like the the lifters,but it goes away and comes back on ,goes away,comes back. My mechanic said it could be exhaust manifold ,another says lifters. My main mechanic told me to change my oil to 20/50 and put in STP oil treatment. that did not work,then told me about another oil treatments? Please help!

If you used STP in addition to “heavier” 20w-50 motor oil, you may now be in a situation where the oil is so thick that it is not able to get through some of the really tiny oil galleries in your engine. Unless you are burning oil to an excessive extent, I urge you to change your oil and to get rid of that “witch’s brew” sitting in your crankcase.

As to the noise, yes, it could well be your lifters, but using heavier oil is NOT going to help them, and–in fact–may make the problem worse. Rather than heavier oil, perhaps flushing the engine might be an approach to consider, but that is just a shot in the dark, and that needs to be confirmed by a competent mechanic who can examine the engine.

Beyond that observation, I can’t really diagnose your noise problem from afar, but I would say that you should definitely avoid that “20/50 PLUS STP mechanic” from now on.

Since you didn’t describe the sound, hard to tell. But it’s not unusual for sticky lifter noise to come and go. I concur w/the poster above that the oil change you did maybe was worth it for diagnostic purposes, but you should now change it back to the oil your owner’s manual recommends. There may be a chemical treatment for sticky lifters to add to the oil, you might ask about that at your local auto parts store. But only add that to your regular oil, not the mix you have in there now.

There’s a sound similar to sticky lifters that can be caused by detonation in the exhaust manifold, either due to a seriously wrong air/fuel mixture problem, or a incontinent exhaust valve. And a similar sound is possible with a head gasket on the fritz. Sometimes that one can be fixed by retorqing the head bolts to spec.

One Possibility:
Locate The Duty Cycle Purge Solenoid Under The Hood And Make Sure The Noise Isn’t Originating There.

A Chrysler bulletin written for Jeep technicians applies only to 2002 - 2004 Grand Cherokees. It says:

“The ticking-like sound may also be described as a tapping or clicking-like sound.
The sound may appear to be similar to the sound produced by a worn or loose
engine valve train component, such as a valve lifter.”

Some of those solenoids have been found to contact the vehicle body when they are supposed to be isolated from it by its mounting bracket. To check your’s you can remove the solenoid from its mounting, but leave it hooked up and see if the noise stops when it’s away from the body.

The fix is a (revised ?) U-bracket and bushing, 2 parts. If interested, get hold of a copy of TSB 25-001-03.

For $10 or $15 you can have some fun with an automotive stethoscope to locate your noise. Sears and auto parts stores sell them.

CSA

Another Guess: Some After Market Oil Filters Don’t Meet Specs For Anti-Drain Valves, Etcetera. I’d Put The Correct Chrysler Mopar Filter On It If It’s Got Something Else.

CSA

You Should See A Version Of TSB 25-001-03 At This Link I Found.

CSA

I would second the idea of getting the 20W50 and the STP gunk out of there asap, especially with winter coming. Putting 20W50 in might be a good idea if you had a 1950s vehicle where tolerances just weren’t that tight, but using it in your Jeep is a great way to starve the engine for oil at startup and possibly blow some seals when running at higher RPMs.

Using a stethoscope should quickly determine if the noise is internal or external. And I strongly advise getting the oil changed to a 10w__ ASAP.

Ok took the 10/50 oil out,brought it to my other mechanic. He pulled everything and showed me it was not the lifters ,but 3 rocker arms that were very loose. He torqued them and the engine runs better,but I still hear this sound softer. What now? please help. Why do I still hear this "tapping’ sound still/? He put 10w 40 in the car,by the way. Thanks,still losing my hair…

The 4.0L I6 has a noisy valve train when nothing is worn or broken but I have seen poorly maintained Jeep engines develop more severe pecking when the push rods wore to a pencil point at the rocker arms. The pecking from a cracked exhaust manifold is much more common though.

For what it’s worth, I know for a fact that your engine requires 10W-30. The reason I know is that I recently did a full tune-up on a 2004 Grand Cherokee 4.0 6-cylinder. There was some question as to what oil I needed to get, so I looked on the owner’s manual online (there was none in the glovebox and it wasn’t my car) and 10W-30 was listed as the proper oil.
Like the other guys said, check that your exhaust manifold isn’t cracked. Also check that none of the exhaust manifold hardware is missing/broken off.
By the way . . . what does “pulled everything” mean? Did the mechanic merely remove the valve cover and discover that the rockers were loose? Or did he actually pull the push rods and lifters as well?
You could still add some of that stuff to quiet noisey lifters.

Yes he did,he showed me the rockers were loose. Yes and pulled the push rods and lifters as well.
What is a Duty Cycle Purge Solenoid? Some mechanics think its this? Please explain.I have added a little Lucas oil stabilizer in it. I dont feel justified i paid for this and still hear it ,sounds better,but its till there???

Any purge solenoid noise could be verified very quickly with a stethoscope.

What I would wonder about is why 3 lifters were loose and the only thing done was to retighten them.
That would not be a cure for a tapping valve lifter problem and is overlooking a root cause.

If the lifters and pushrods were pulled I would hope the bottom of the lifters and the cam lobes were inspected closely. Tightening the lifters up and removing all looseness does not mean they won’t tap anyway.

Pulling the lifters on the Jeep I4 and I6 engines calls for removing the head but I am certain in my recollection of pulling lifters out through the head. There is no adjustment in the valve train. Rocker bolts are torqued down. There is no “tightening” to remove valve train slack.

You might also have other low oil pressure issues. It is a check of the actual oil pressure and it should be done cold first then hot with the correct oil weight. Excessive journal wear or gunking in the small passages can lead to general or specific oil delivery issues. The engine is a bit young but if pressure is an issue now it will not get better with age.

Guys, I just checked my admittedly cheesy Haynes Repair Manual.
Apparently, it’s possible to remove the rocker arms and pushrods without removing the head. I haven’t done this myself, as the 2000 Grand Cherokee 4.0 on which I was working wasn’t making any clicking noises.
I can only hope the mechanic closely examined the removed components for wear.
I suppose you might identify an extremely weak lifter by pushing down with the upper pushrod end.
But you still wouldn’t be able to see the actual lifter at that point, as it’s too far down.
Just looked in a different section of the book. They have a picture of someone removing a lifter, using a magnet, with the head REMOVED.
RodKnox, you were right.

Personally, I doubt the mechanic actually removed the lifters. If you went to the trouble of removing the head and examing the lifters because of a noise, anyone competent would have replaced them. I probably would have replaced them all, to be on the safe side.

Jeepster, an evap purge solenoid allows stored fuel vapors to be pulled into and burned by the engine at the appropriate time. When it’s doing its thing it’ll make a clicking/pulsing noise. I’m not sure where it’s located on your Jeep.

He check even with JEEP, and they said that sometimes replacement of the lifters would not help the problem. I saw blog after blog about people stating this. the oil pressure is up considerably. the mechanic stated that the rocker arms looked good and he examined them. 3 needed to be torqued or tightened. Dont get me wrong it sounds much better, new oil pump,new fuel pump(which i needed,the hum was killing my musicians ear!) But why would JEEP tell him not to replace the lifters, I was ready for that option? I have now changed my oil down to what the manual says 10w 30, with no “additives” in the crank case. I need more of an exact answer guys,thank you for taking the time out to help me.

Tell me more about purge solenoids and how they can omit the same types of "ticking"
Thank you and Merry Christmas to all of you!

Jeepster, in my last post, I told you what the function of the purge solenoid is, but I still don’t know where it’s located on your car.

This is what it apparently looks like.

http://www.rockauto.com/catalog/moreinfo.php?pk=3789891&cc=1420737

Your evap canister is in the left rear fenderwell area, behind the tire. The purge solenoid might be there, but some cars have it in the engine bay.

Does the noise “speed up” as the engine speeds up?

If yes, then forget the purge solenoid

If yes, then it’s probably valvetrain noise, probably the lifters.

One more question, is the noise present as long as the engine is running?

If the lifters were loose then there’s a problem in that area; assuming the lifters were retightened as claimed.
This engine should use bolts and pedestals so if the lifters were loose this means the bolts are pulling the threads out of the cylinder head or the lifters are failing. The latter is more likely than the former.

It’s possible to snug up a rocker arm on an old Chevy small block that uses rocker studs but raises the question of how does someone tighten up a bolt on a pedestal mounting… :wink: