Knocking?

[juan214]

So boys and girls seems I developed a suspect knock. Just coincidence had my A/C serviced and ask to have it evac, flush, recharge (with oil) about two weeks ago. The only things done prior to this in order are front brakes pads, brake cables, parking brakes shoes & hardware, right rear brake line and bleed, AWD fused reinstalled, State Safety Inspection (it passed), and fuse for A/C reinstalled for prior to service. A few days after a/c service I developed a vibration/ knock. I could hear a heat shield rattle a little louder (not the issue). When I turn the a/c or heat on I get a knock. Roll the windows up or down and hold the button the strain makes the knocking noise. I turn the steering wheel occasionally get the knock. At idle it will come up occasionally .

This range of cause and effects has me puzzled. Could be a simple engine knock? At acceleration no knock, and truck seems to run as normal. It is not the typical engine tick.

No Check Engine light

Any suggestions as to what to look for would greatly appreciated. Thinking may be an EGR issue? Rod Bearing? I just heard it after start up just today.

 

[docraymund]

Do you hear it from the engine itself?

 

[juan214]

It emits from the engine or trany, I can hear from the wheel well, seems like a hollow knock. I could not hear until I was parked between two buildings and it echoed back. If goes away when the causes stops or it accelerates. Truck runs and shifts fine. Not sure if any has come across knocking under (I guess) strain? With the a/c or heat on I get a knock. Roll the windows up or down and hold the button the strain makes the knocking noise. I turn the steering wheel occasionally get the knock. At idle it will come up occasionally.

I thinking spun bearing, torque converter, possible transfer case. I might pull the fuse for the AWD today.
I've had blown plugs and a split valve guide and those worse, louder, and continious.

If its the engine I should hear it continuously, unless its faint and coming.

Thanks for the reply.

 

[Plati]

Sometimes with these older vehicles ... it's best not to listen too closely.
If I had tried to chase down every noise my 2003XLT has made, I'd be broke & in the psycho ward. As it is, I still have a few dollars so I'm not broke.

 

[docraymund]

If it's from the engine, the noise might get louder upon slow revving or it may appear at cold starts and disappear when the engine gets hot. If it's from a bad timing, it will appear upon hard acceleration especially with a/c on and you're driving uphill (might be from bad timing chain).

You might want to buy a mechanic's stethoscope to help pinpoint the noise. Just remove any dangling things on your body to be safe.

You also might want to park again between two buildings to help in locating the sound. Try it on a quiet day. Connecting rod noise may sound like an old diesel engine at idle.

If it appears when you hold the power window switch, check the connections to the alternator for looseness and check the alternator output with a multimeter. Should be 13.5 to 14.4 volts.


Good luck!

 

[juan214]

Sometimes with these older vehicles ... it's best not to listen too closely.
If I had tried to chase down every noise my 2003XLT has made, I'd be broke & in the psycho ward. As it is, I still have a few dollars so I'm not broke.

LOL, trying to avoid a pound a cure (a newer truck) for as long as possible