I haven't been around cars since forever like some of you knowledgeable folks. Is this rod knock? Seems to be coming down low from the front. Gets a little quieter at higher RPM or is drowned out by the rest of the engine. I had put this in Ask A Question but it fell down pretty fast. The serp belt is disconnected so it's nothing like the water or P/S pumps. I'm hoping it could be the oil pump but I'd love to hear some advice or solid opinions.

Sorry for crap video, my phone fails and wouldn't focus. About the only thing you can make out for sure is the rust lol The mic is on the bottom of the phone so thats why the picture doesn't make much sense


Quick specs: 1999 4.0, manual transmission.

PO said he always used Mobil 1 5W30 or 10W30 and AC Delco filter (which apparently are same construction as our beloved FRAMs...). I've done two oil changes to it, one with Mobil1 5W30 and the latest with Rotella T6 5W40. Mobil 1 filter each time. Noise hasn't noticeably changed with oil changes.

I have towed about 2000 pound U Haul with some old furniture/garbage in it and didn't have any problems other than insane gas consumption lol

 

sounds a little noisy possible lifters. whats you're oil pressure at hot idle and what is it cruising down the highway above 1600rpms hot?

 

???Could you post another vid, rev it a little a few times, also hold it a bit at mid, (2k) Rpm for a few secs?

I know the (condenser?) mike is weird, but man what a hiss. You got a vacuum leak? How many miles?

 

Doesnt sound like its knockibg hard like a rod would check your flexplate it sounds like its loose and when it comes loose it slunds like a rod knock

 

Manual transmission, no flex plate. I would read through this recent post and disregard all the talk of loose flex plate bolts.

https://www.cherokeeforum.com/f2/can...-motor-144417/

 

Thanks very much guys, I will read that thread thoroughly once I'm done with the BBQ lol.

Flintstone I will definitely do that. I'll need a helper to hold the phone though. Probably got a vacuum leak and I gotta check the manifold bolts too, though I never realized the hiss was that bad

Oil pressure based on the in-dash gauge is excellent, was actually spot on when I ran Mobil 1 xW30. I've got the metric gauges and don't really pay attention to the numbers but it's right where it should be (I remember doing the conversion). When I changed to heavier oil it was just a bit higher.

327211 kilometers

 

327211 kilometers...so it's not really heavy...Good. (Kidding!)

Yea more would be nifty. Wanna say a lifter. Can hear the tick from above, and the cam lobe hitting the lifter can indeed make a knock.

A rod might rap a little louder as you goose it a little. Also that first second the oil pressure is still at idle pressure.

Post us up some more video and lets tee what people think. I'd hold the phone and work the throttle with the other hand...But I'm a yank, not Canadian.....

I might listen for the hiss with a length of hose, or use short little shots of starting fluid. The engine sound will change if you hit it. Of course you don't want much of that on there, but it evaporates really quickly. Don't forget the lower injector O rings need to seal vacuum.

 

Sounds too shallow and tinny to be a rod, IMHO. More like a stuck or collapsed lifter.

 

Welp I ended up going camping instead of doing the video, one day I tried pulling plugs and the Jeep kindly reminded me that there's quite a lot of voltage running through there while its running. Ouch lol

In the mean time I came across a lot of information about sticky lifters. Something I noticed was that on cold startup the engine runs smoother and there's no clacking noise for up to a minute. Then the noise shows up and the engine stumbles a tad. When hot or even sorta warm it does it almost immediately on startup. I noticed a lot of other people report this showing up after several minutes, and posted they run say 10W30 or 15W40. I run a synthetic 5W40 so less time to warm up makes sense.

There is no MMO in Canada (stopped selling it a few years ago... not CSA approved or something) so I picked up a can of STP Multipurpose Motor Treatment which looks to be similar to MMO. Some thin oil and naptha, no alcohol. Looks like a Seafoam clone. I did the "engine flush" which said to dump 1 can per 5L oil and run for 15 minutes. Well Mr Green Jeans has about 6L in him with the filter so I put the whole can in and ran it for around 20. At the end the noise is almost totally gone and the idle is a lot smoother! I guess its pretty much a stuck lifter and not totally collapsed, though who knows what damage has occurred while this problem's been ongoing (nobody to blame but myself for that). I drained out the STP and old oil and spun on a new filter with a 6cyl size of that "Restore" stuff everyone seems to be a fan of and Rotella T6 5W40. Noise still gone and the top end seems a little quieter than before. I forgot to shake up the Restore can first, though, so it looks like a lot of the metalic goo didn't make it in. To be honest to see that kind of separation and crud lurking in the bottom from being on the shelves... I'm kinda glad that it didn't make it in.

Next oil change I'm going to dump the old stuff first and run some more of the STP treatment with el cheapo 5W30 or 5W20 to flush it before doing a fresh fill.

We'll see if it stays this way...

 

Have you considered setting up a small smuggling ring? Could put it in Molson cans so nobody gets suspicious.

 

Yeah right, what could possibly be so inconspicuous about importing beer produced locally? Lol. Though I think its a similar viscosity to Guinness...

 

Well... ah....I never said I was a good smuggler.
Besides, I only get as far as Thunder Bay in the summer, you'd have a very long drive. Clearly not a well thought out plan.

 

I think you're on the right track. What filter are you using?

 

Hey you should know me better than that lol. I've got a Mobil1 M1-301 on there. When I bought it there was an ACDelco unit on there of the same internal design as your Favorite Reckless Accessory Manufacturer

 

I love the aditional acronym!!!!!