nicksan

I forgot to mention I did check for cracks and saw nothing, It looked really clean. The Transmission was rebuilt two years ago.

I started it up and let it idle and I did not hear the knocking sound, I revved it at the engine compartment and still could not hear the same sound I heard while driving the other day. I dont drive it so its hard to say. I am going to take it out again this weekend and rediagnose the sound, when and how I am driving that makes the sound.

If it were a rod bearing would it be makeing the knocking sould all the time even at idle??

Thanks.

cruiser54

Yes, it would be knocking all the time....

nicksan

Thanks....

What does a AW4 sound like when it has been deprived of fluid for a while?

nicksan

The sound appears for a few seconds right after starting the car, then it quickly goes away.
While cruising around 30mph the sound is not there but when I start to accelerate it gets louder and louder then goes away if I tap the brakes or when the gears shift (auto trans).
When the car is idling the sound is not there.
When the car going very fast the sound is not there.
This is a tough one to diagnose
Its so loud its hard to believe its a rod bearing because I would think it would have exploded by now.
I should have another look at the engine mounts again I guess.
I am crossing my fingers its not the engine....

nicksan

Today I took my xj to a trans shop. The owner drove it around the block several times with me in the car. He does not think its the transmission and determined that the noise is coming from up front somewhere but could not tell me it was the engine making the noise.
Again the noise does not happen at idle, even when I rev it very high.
I bought some 10w40 and lucas oil stabilizer to see if the noise is altered at all by a thicker oil and the lucas.

cruiser54

Skip the Lucas crap. Look at your harmonic balancer located on the front of the crankshaft.

nicksan

I finally found time to look at the jeep. I checked out the harmonic balancer as cruiser suggested and it looks like its in very good condition, possibly replaced recently by PO, but that was definately worth looking at.

While poking around, I noticed that the metal part of the passenger side motor mount is resting on the engine bracket, (metal to metal) I got a large screwdriver and pried on the metal part of the mount and there is tension pushing the mount to the bracket causing them to come together.

Its tough to see if there is any wear or flattening from the metal on metal contact but this could be the source of the noise.
I guess I overlooked this before when I replaced the drivers side.
I wont be able to replace it until next weekend and I wont be driving it until its replaced.
I returned the lucas additive and exchanged it for a temperature sensor since mine is not working.

Thanks.

cruiser54

Good job!!

nicksan

I am crossing my fingers and hope that this is the source of the noise.

I`ll post the results after I change the passenger side mount.

Thanks.

nicksan

So, I finally got time to change out the passenger side motor mount hoping it is the source of a horrble noise I have. I did the drivers side a few months back and it took 10 to 15 minutes, pretty easy..... Not so with the passenger side.
It took almost 3 hours in the hot sun, I was going to buy a popup just for this but figured it would only be a 15 minute job .
After removing all the nuts and bolts the stud on the mount was being held in place by a scissor type action of the sheet from the mount and the frame.
After prying, pulling, and pounding the stud from underneath I finally got it removed.
To my dismay, the new one would not line up at all So I played around cutting and fitting with no luck, I took a good look at the old one and it had been replaced because it didnt have any dry rot, rubber looked good and had just one little cut in the rubber (other than what i did to it, LOL) So after all that I reinstalled the old one but of course it took about half hour because it went in about as easily as it came out.
I took it out for a spin and unfortunately the noise I have is still there
But... at least I ruled out the mount as a cause of this unknown sound and I know the mount is in good condition, except I now believe I have a bigger problem, I am convinced the trans and the engine are somehow shifter foward about an inch or a little more because when i did the trans mount a few months back I had the same problem with the crossmember not ligning up and having to drill holes and pry to get the crossmember on.

I do have a couple questions.... The mounts for the drivers side and passenge side on a 95, 2WD are the same right? and I have about a 3/16 ths space between the motor mount and the engine mount with a few threads of the large bolt showing is that something to be concerned about?

Thanks and Sorry for the long rant....

nicksan

Unfortunately I have come to find out it is the engine

I was thinking, or maybe wishfull thinking that it was something else.
Since the noise was not noticeable while idleing and didnt appear while manually pushing on the accelerator cable under the hood I was hoping is was something else but now it is very noticeable (Dramatic Increase in ambient temp?), not at idle though, so maybe I have some time before it explodes....

Oh... and I also have an exaust leak at the manifold....