dzzavid

Hello,

I have a question and hopefully some one could give me some advice. I just purchased a 00 Cherokee 4.0 4x4. The body has 194,000mi on it. The motor was replaced 6 months ago by car-x with a used motor. Everything for the most part runs great, i have a smal valve gasket oil leak that i need to take care of but i have noticed that i can hear a slight knock at idle, only after the jeep has warmed up to operating tempature. You can only hear the knock inside the cab, and it either goes away under acceleration or is drowned out by other motor noise. I have tried and tried but i can not hear the noise outside of the jeep or in the motor compartment. Has any one experienced something simular?

I am planning on doing the valve cover gasket this weekend and i am goign to change the oil then as well. The only thing i could think of is very cheap oil.

Any suggestions are appreciated!

Thanks in advance

Dave

dzzavid

Also some more information, from inside the cab is sounds like it is coming from the lower passenger side. every once in a while on idle, i get a strange rattle that i first thought it was just a loose center console, or something similar but i have read a few post that make me believe my torque converter bolts may be loose.

arsxj

Go out and kick your catalytic converter. If it rattles then bingo

fantic238

If it's a knock and not a ticking noise it's something coming from the lower end. Probably a piston rod bearing. It might go away with SAE 20W 50 or 20W 60 oil.
If it's more of a ticking noise it might be a collapsed tappet or a pushrod.

DBGrif97

Or it might be the knock sensor... I have the exact same problem on my wife's 97 Cherokee sport. I haven't had the chance to check the knock sensor to find out for sure if that's the cause, but it seems the most reasonable given the volume of the knock. If it was a piston rod bearing it would probably be producing a lot more noise.

fantic238

There is no knock sensor in a '00 ckee nor in your wife's '97.

dzzavid

Well a few days ago i put some motor honey in the oil just to see if it quieted it at all, i figured it wouldn't hurt since i am doing an oil change very soon any way. There was no change at all after the motor honey.

fantic238

How's the oil pressure? At cold, at idle and hot.

joshbovaird

my 98 does the same thing my crank sensors bad im hoping that might have something to do with it

dzzavid

It always stays very close to 40. it goes up and down about 5-10 psi if its cold or i am idling.

I am really hoping it is the torque converter, last night it didnt do it at all untill about 20 minutes after i started it. Then i parked it, shut off the motor and started it back up and it was not making the sound again. I really dont think it is a motor problem. I will post to let you guys know what i find when i take the access plate off either tonight or this saturday.

-thanks!

fantic238

Could be the timing chain as well.

bryanboonern

I can't remember what it is called, but there is some type of emissions something or other (love the technical terminology) on the passenger side fire wall that "knocks." It is normal. I was concerned about this on mine as well and a friend disconnected the line to it and it went away. When plugged back in, it started again. You can feel it knock if you put your hand on it.

dzzavid

Thanks for the heads up i will look into that as well

dzzavid

i did some searching on this site and general googling with no luck, can any one elaborate on the emission system Bryan mentioned?

00XJ

i had same problem but a little thicker oil took care of it.