engine problems PLEASE HELP!

[Jeep liberty 3.7]

I have a 2003 jeep liberty 3.7 and it started knocking. It's very loud I can hear it from inside the jeep! It is also misfiring bad and don't have much power. It's doesn't make The noise all the time it does sometimes when idling and and when it's between 1500 to 2500 rpm. Sometimes it don't do it at all just runs rough. Anyone know what wood cause this? thanks for looking

 

[Conundrum2006]

Sorry to say the engine is about throw a rod or perhaps has dropped a valve shattering position.

Unfortunately I can’t think of anything that would make such a loud noise and misfires while being a minor problem.

Compression test will probably show 0 compression or compression below 100psi causing the misfire. Other possible causes bad spark plug, fuel injector,ignition coil.
If it dropped the valve maybe repair job to cylinder head, but with a sound like this my guess is catastrophic failure has happened or is about to.

Unless you have the background to rebuild I’d just try to source a good used engine. Maybe rebuilt if you can afford it.

However you can test to be sure, in this situation I’d do a compression test find the cylinder with bad compression and scope those cylinder to see what kind of damage there is. Automotive stethoscope to find where the sound originated.
I wouldn’t be driving this jeep or run the engine more than necessary.

Other here have a lot of experience with 3.7 engine and may have better advice.


Edit: forgot to say if you do test and the compression is good, then locating the sound is next. Very off chance the sound is transmission, torque converter bolt, something belt driven.

Test the belt driven by removing the belt. Test for rod knock by disconnecting the ignition coils one at a time to see is the noise goes away. We can get better instructions on these testing methods if you need them.


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[ltd02]

Do you have a CEL? Is it flashing? If you do, get the code. Pull the valve covers and have a look. Might just be a dropped rocker arm. Mine did this when the lash adjusters were failing. A new one fixed it and it wasn't that tough to do.

 

[Samsolo49]

Do you have a CEL? Is it flashing? If you do, get the code. Pull the valve covers and have a look. Might just be a dropped rocker arm. Mine did this when the lash adjusters were failing. A new one fixed it and it wasn't that tough to do.

I guarantee you it's a valve, bad design on those. Entire rebuilt engine with a 5 yr unlimited warranty is $2500 on eBay, free shipping. If you go that way use synthetic oil in the new engine, seems to help with that.

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[ltd02]

Could be but maybe rule out the minor and simple things first before panicking. When I threw the #2 exhaust rocker I thought the thing was gonna explode. Did it three times over about a year. After the second time I bought a lash adjuster (Melling). When it dropped the third time I just installed the new adjuster while the rocker was off. Never did it again. And this was an engine that overheated bad a couple years earlier due to a failed fan relay.

 

[Jeep liberty 3.7]

The check engine light is on and sometimes flashes..the codes are p0302 cylinder 2 misfire p0306 cylinder 6 misfire and a code for a bad oxygen sensor.. I'm thinking the rocker arm to because it was running grate I drove it about 60 miles Sunday. And Monday morning on my way to work it started making that noise and not running good

 

[ltd02]

The check engine light is on and sometimes flashes..the codes are p0302 cylinder 2 misfire p0306 cylinder 6 misfire and a code for a bad oxygen sensor.. I'm thinking the rocker arm to because it was running grate I drove it about 60 miles Sunday. And Monday morning on my way to work it started making that noise and not running good

All you'd have to do is pull the right side valve cover and see both cylinders valves. I have to admit if these things drop valve seats they usually are #2 for some reason. I thought the worst when mine acted up but turned out to be nothing. If the rockers are okay then I'd start to think valve seat and do a compression check. You might even be able to see a tweaked valve just by looking. Was this engine ever overheated?

I also had a hard misfire (with flashing CEL) with a p0306. I shut it off and started it back up again about 30min later and no misfire or flashing CEL. Think I might have gotten some water or coolant in the plug/coil area of #6.

Now that I think of it, a few years back I had a wicked hard misfire (bucking and popping and sometimes a flashing CEL) that would come and go with my 2011 Avenger and it turned out to be an O2 sensor. I would wouldn't dismiss that either. That can cause some cylinder specific misfire codes too. Was yours an O2 sensor code on bank 2?

 

[Jeep liberty 3.7]

I will pull the vale cover off tomorrow and check. I bought the jeep used almost 3 years ago and it's never overheated on me

 

[ltd02]

Not a bad idea to have a "scanner" that can do a bit of live data. Doesn't have to be too sophisticated but its real nice to see fuel trims and O2 sensor voltages on the fly when these things happen. Even a bluetooth type sender (< $20) and an app like torque (free version) will allow you to see some of this stuff.

 

[kuench]

If it idles like this, then it's a rocker.

https://youtu.be/NXRrOyIdEJA

The sound was worse with higher rpms and under load. I was able to limp home.

 

[Jeep liberty 3.7]

Yes that's exactly what it sounds like. I plan on going out in a few minutes to pull the valve cover

 

[Jeep liberty 3.7]

It was the rockers! Cylinder 4 and cylinder 6 Both for the exhaust. I put them back in and it's running grate.. I was planning on buying new rockers but they seemed good. no damage and the bearing in the middle was good. But I did notice some black sludge and I cleaned as much of it as I could. Is there any oil additives that will help with that?
Thanks everyone for all of the help!

 

[Aceofspades]

Not too sure what these engines like as far as cleaners go but ATF was always a go-to for a cheap flush before oil change. You remove a quart of oil and add a quart of ATF. Run till warm. And drain. Knowing my Jeep it will already be a quart low anyways.

 

[Conundrum2006]

Don’t flush the engine! ATF flush may be different I haven’t tried it, normal flushes will just knock any built up crud lose and get caught up in the pan eventually blocking the oil pick up. You need to slowly dissolve the crud. Here’s what I tried in two different vehicles Shell Rotella T5 and T6 is a Diesel oil with a lot of detergents, T6 is full synthetic , T5 is a synthetic blend. I used them in my 300k 4.0 Cherokee and in laws Hyundai which went years (and many many miles) without a oil change, the Hyundai engine is as close an example as I can get to the 3.7, I watched as each oil change the built up sludge slowly dissolved, it was a thick build up. Year and a half maybe two years later we pulled the valve covers as part of maintenance changing the spark plugs. It went from awful to what could be expected from a high milage engine. Which I had done this with our commander, we let a shop run a flush that ended up dropping so much crud into the pan I swapped out the motor, I tried everything but the ATF flush to clear the engine, it was so bad it’d clog oil filter in a few miles normal driving or sooner at higher rpm.


Kudos on finding the problem! I’m glad to be wrong and glad it was an easy fix.


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[emily_2000]

New engine suggestions

i HAVE AN 04 LIBERTY 3.7l AND i GOT IT OFF CRAISLIST ABOUT 2 YEARS AGO... tHE LADY TOLD ME IT HAD ISSUES EITHER THE O2 CENSOR OR CATILLITIC CONVERTER... iT USED TO OVEREAT ANYTIME THE TEMPERATURE WAS OVER 70 OR IF SAT STILL FOR TOO LONG WICH TURNED OUT TO BE THE FAN... IVE NOW HAD TO REPLACE JUST ABOUT EVERYTHING UNTIL I STARTED IT TO A LOUD KNOCKING ONE DAY...i NEED A NEW ENGINE AND i WAS WONDERING WICH WERE THE BEST/MOST COMPATIBLE?

 

[ltd02]

i HAVE AN 04 LIBERTY 3.7l AND i GOT IT OFF CRAISLIST ABOUT 2 YEARS AGO... tHE LADY TOLD ME IT HAD ISSUES EITHER THE O2 CENSOR OR CATILLITIC CONVERTER... iT USED TO OVEREAT ANYTIME THE TEMPERATURE WAS OVER 70 OR IF SAT STILL FOR TOO LONG WICH TURNED OUT TO BE THE FAN... IVE NOW HAD TO REPLACE JUST ABOUT EVERYTHING UNTIL I STARTED IT TO A LOUD KNOCKING ONE DAY...i NEED A NEW ENGINE AND i WAS WONDERING WICH WERE THE BEST/MOST COMPATIBLE?

Check out this thread: http://www.jeepkj.com/forum/f202/engine-swap-overview-53270/

 

[ltd02]

Yeah, I'd avoid a flush. We used to use ATF back in the day but I'd be afraid that this new fancy ATF with all the different additives might do more harm than good.

Could try this since you can do it slowly and dose it: https://www.hotshotsecret.com/shop/stiction-eliminator/

 

[JasonJ]

AutoRX has good results, you add a little to each oil change- changing it at specified mileage intervals. It works slowly, which is why it works at all. Might take you 6 months or more to clean it all out, but it does so without damaging anything.

 

[Aceofspades]

Yeah. I don’t recommend anything I haven’t tried. I used the atf a few times before switching to full syn. And I I feel like the full syn oil cleaned the engine better over the course of the year. It also cleaned it well enough to allow the cam seals to leak. But that was ok with me because that vehicle was my summer car and I had plans for the engine that require replacing those anyways