Loud knock, i'm clueless!

[ronjcar]

So everything was perfectly fine yesterday morning and then i go to start my jeep up about 14 hours later to head to work and i have an extremely loud knock under the hood and my check engine light is now on. It's not consistent but it happens every 2-5 seconds. I just changed the oil and put 5w20 in it thinking because it's so cold that oil wasn't getting to the top of the motor as fast and put in some valve and lifter treatment. I'm thinking it's a valve making the knock but it sounds like something is ramming off some plastic really hard. Any ideas?

I do have a 3 year warranty and it's going to the garage Monday but if it's something i can fix i would rather grab my mechanic buddy and get it done.

 

[ronjcar]

I tore the valve cover off the passenger side to find a rocker arm laying there and 2 cracked brackets. not sure what the brackets are called though and i'm trying to call around for parts

 

[LibertyTC]

eek...another failed rocker..How many miles on this 3.7?
Got a photo of the bracket and rocker laying in there?
I'm sure others may chime in on this one..hopefully valve stem is not bent and you can just replace the rocker. Any cracks in the spring?

 

[ronjcar]

No pics, but the rocker was just laying in there and 2 cam caps were broken. I just finished putting it back together, now i'll just wait til the dealership comes and picks it up monday and fixes it for me. Hoping i didn't void my warranty but i just had to know what the hell was knocking in there lol oh and it's an 04 with 85k miles on it.

My reasoning for letting the dealership deal with it was simply because no parts store in my area carries Cam Caps and i don't feel like waiting 5-7 business days for them online.

 

[CactusJacked]

A dropped valve seat could be one reason for the rocker arm popping off, it happens with these engines. I'd make sure the dealership thoroughly explores that possibility, the rockers don't fly off just for the heck of it. Good thing you have a warranty.

 

[ltd02]

Better to let them deal with it if they will cover it. Especially with the damage it caused. I've had my number two exhaust drop twice in a few years (passenger side too). Just seemed to happen without warning but I've got 166k on mine now. I was lucky since it was the exhaust so it just slipped out of the way and didn't contact anything. Just got a wicked misfire. I'm guessing yours was an intake rocker up top? I bought a couple lash adjusters in case it happens again but I sort of think it's the valve sticking momentarily taking pressure off the rocker and out she slides. Just my theory. Why are you using 5w20? I always use 5w30 so doubt the 5w20 had much to do with it but just curious. Should be good to like -20F. If you want thinner when cold you'd go with 0w something. Your just running thinner oil when its warm.

 

[nullptr]

All this talk about dropped valve seats with no warning is making me nervous. nervous.gif

 

[ltd02]

All this talk about dropped valve seats with no warning is making me nervous. nervous.gif

I've seen quite a few posts at different places and even Youtube vids and such pertaining to the 3.7 and 4.7s. But remember, there are millions of these engines out there so I don't think it's very common as the percentage is pretty low overall. This includes all 3.7 and 4.7 Dodges etc out there. Mine did this shortly after and overheat and then about two years later. Not real hard to pop it back on but both times it did it right at startup. I don't worry about it personally thanks to AAA.

 

[kuench]

Mine popped on a morning when it was -30°C. Luckily it was on the last cylinder on the passenger side and just slip off. Still, an expensive sounding noise.

 

[ronjcar]

Mine was the 1st one on the passenger side, #3 intake i think? I was going to just pop it back in but after seeing 2 cam caps split in half i threw it back together and called the dealership. It did happen on startup after sitting 14 hours in -10 and colder temps. As for running 5w20 my friend who has been a mechanic for chrysler for 10+ years told me he generally puts it in all "newer" jeeps for the winter and goes back to 5w30 in spring. Don't ask me why lol!
I'm beginning to think there was some underlying issue though, even though this seems to fairly common problem with the 3.7 and 4.7 from chrysler. Also i noticed it must have happened on the opposite side too from a previous owner because the valve cover was patched. Hopefully i can convince my buddy into a motor replacement!

 

[ltd02]

Mine was the 1st one on the passenger side, #3 intake i think? I was going to just pop it back in but after seeing 2 cam caps split in half i threw it back together and called the dealership. It did happen on startup after sitting 14 hours in -10 and colder temps. As for running 5w20 my friend who has been a mechanic for chrysler for 10+ years told me he generally puts it in all "newer" jeeps for the winter and goes back to 5w30 in spring. Don't ask me why lol!
I'm beginning to think there was some underlying issue though, even though this seems to fairly common problem with the 3.7 and 4.7 from chrysler. Also i noticed it must have happened on the opposite side too from a previous owner because the valve cover was patched. Hopefully i can convince my buddy into a motor replacement!

Passenger side (US) is 2-4-6 front to back. Intake valves are closer to the intake ("inside" the cam) exhaust are closer to the exhaust manifolds so "outside" the cam. So yours was a number 2, front is the intake, second is the exhaust.

What year is your KJ? You should fill out your profile. It helps alot. Is the cover plastic or did someone actually patch a metal one. Can't remember when they switched but older ones have metal covers.

I don't think the oil you are using is a big deal but I always run the recommended weight.

 

[ronjcar]

It's a 2004 limited and has plastic valve covers

 

[Hockeygoon]

So everything was perfectly fine yesterday morning and then i go to start my jeep up about 14 hours later to head to work and i have an extremely loud knock under the hood and my check engine light is now on. It's not consistent but it happens every 2-5 seconds. I just changed the oil and put 5w20 in it thinking because it's so cold that oil wasn't getting to the top of the motor as fast and put in some valve and lifter treatment. I'm thinking it's a valve making the knock but it sounds like something is ramming off some plastic really hard. Any ideas?

I do have a 3 year warranty and it's going to the garage Monday but if it's something i can fix i would rather grab my mechanic buddy and get it done.

You got a 3 year warranty on an 11 year old Liberty?

 

[ronjcar]

You got a 3 year warranty on an 11 year old Liberty?

Yes because I ran out of options due to bad credit and had to buy from JD Byrider and with them you get a 3 year 36k mile warranty.

 

[ftaa]

Yes because I ran out of options due to bad credit and had to buy from JD Byrider and with them you get a 3 year 36k mile warranty.

if its a lubrico warranty its not worth to wipe your ass with .

 

[ronjcar]

if its a lubrico warranty its not worth to wipe your ass with .

Not lubrico lol. Getting my baby back today at 5, from the parts list it seems as if the cam jumped because they had to replace quite a bit and it only cost me $25.

 

[ftaa]

great to hear happy trails!

 

[CalcityRenegade]

if its a lubrico warranty its not worth to wipe your ass with .

My brother had a truck with their warranty and the transmission failed after he had the truck for a couple weeks, They tried every excuse under the sun to deny the claim, When his lawyers letter head slid across their desk they sure changed their tunes and got it fixed.

 

[ftaa]

My brother had a truck with their warranty and the transmission failed after he had the truck for a couple weeks, They tried every excuse under the sun to deny the claim, When his lawyers letter head slid across their desk they sure changed their tunes and got it fixed.

but you shouldnt have to have a lawyer on retainer for a friggin legit warranty issue ...

 

[twowings]

but you shouldnt have to have a lawyer on retainer for a friggin legit warranty issue ...

In a perfect world, yes....but you'd better have one on retainer if you sneeze and fart at the same time in this world....:gr_grin: