So, I’ve had lifter tick for a while. It’s there on cold start but goes away once warmed up.

today I went to the store and when accelerating out of my neighborhood I hear/felt a little “poof” and now I have a loud constant tick noise. Engine still runs smooth, no misfire. No noticeable loss of power. But tick is noticeable at idle and acceleration.

stock 4.0 and drivetrain. Automatic.

 

Can you get a video or audio?

 

Might want to remove valve cover and take a look/listen before something really goes "poof"

 

here is a video

https://www.dropbox.com/scl/fi/nnekb...g6dvb7gct&dl=0

 

I’ll do that here in a bit. What should I look for?

 

See if you can localize the noise. Look for broken valve springs, funky rockers, bent push rods, any slop between rocker and valve, scrap metal.

This is all assuming the new noise you're hearing is coming from the valve train. First thing you gotta do when you open the hood is zero in on the noise. Who knows, may not be related to your earlier tick.....could be a broken piston, Dr Doom here.

 

A mechanics stethoscope will be very helpful in locating the location of the noise.
When my motor had a tick, it ended up being the distributor, but it sounded like it came from the front of the motor.
hope this helps

 

I literally just did this. To be honest it all sounded the same to me.same sound on cover, oil pan, etc

 

A piece of garden hose. Hold one end to your ear and move the other end around to pinpoint the noise location.

 

Next test, remove the serpentine belt and start the motor, just long enough to hear if the tick is there or not. That will eliminate all the moving items on the motor that are powered by the belt. If the tick is gone, then you have individual items to look at, water pump, power steering pump, a/c, alternator, idler pulley. If the tick is still there, check for wobble on the distributor shaft, it shouldn't have any lateral movement. This is assuming you did the valve cover and cleared the valve train from the ticking.

After listening to your video, it seems more pronounced on the drivers side of the motor...I am thinking it almost sounds like an exhaust leak...maybe someone with more hands on experience could chime in and either support that theory or not.

 

Good advice!
I thought my motor was going to the scrapyard until I slackened off the belt and realised it was just the power steering pump.

edit: I listened to the video - hard to tell. It could still be an ancillery rather than the motor. There's a deep thumping noise as well as the tick, I'd definitely do the belt. My power steering pump sounded a bit like this and only got louder. It worked fine though.
Also, can we hear the hiss of a vacuum leak?

 

On my 01, there is a small "can" with a connector and vacuum hoses on it just outboard of where the heater core hoses run into the firewall. Its something to do with emissions but when working it emits a loud tic tic tic every half second or so. If you take connector off it stops but sets a code. Might want to that.

 

change the oil and get something to feel around in the pan. cracked piston skirts happen on these engines all the time.

 

any update on this from the original author

 

Rod bearing on cylinder 5.

A little sad. Ive had my xj for over 20 years, 275k miles. I changed the oil and filter religiously every 3300 miles. Last oil test was very good. Guess its just a fluke.

Oh well, new motor on the way.