I appreciate any help with my 03 Durango 4.7. The noise started about 19 months ago/10k miles ago. My mechanic said it was the A/C compressor and when it got too bad;loud I would need to replace. A few weeks ago, I switched to a synthetic oil and the noise appeared to get louder. Removing the drive belt did not silence the noise, so I guess it is in the engine.

Below is a link to video of the noise. 130k miles. Head gasket and timing chains/guides/tensioners were replaced 45k miles ago. The "speed" of the noise increases with RPMs. The noise is persistent at startup through operating temp and beyond -- does not stop. Using a mechanic stethoscope, it appears to be loudest at the front passenger side of the engine around the A/C compressor. Any ideas of what the noise could be? Thank you in advance.

 

Take off the serpentine belt and run it for a quick minute. If you still hear it, it's not the compressor or anything in the belt path.

 

I appreciate the response. Yes, I removed the serpentine belt and the noise is still there.

 

Sorry, I missed that part in your initial post. It sounds like a valve issue. Are you getting a check engine light? If so what are the codes? You may need to pull the valve covers, at least the one closest to the sound.

 

Great suggestion. I will do that. There have been no error codes. Are you thinking a valve is stuck open (eg dropped seat or bad lifter)? Also, here is another video taken while I open the throttle with the mic near the oil fill. Thanks!

 

Maybe. Being that there are no codes, it's hard to tell what is going on there. I recently replaced all my lifters due one seizing and ejecting a rocker, but it generated a code. Did the noise start suddenly, or develop over time? How is the oil pressure and has the engine been run low on oil?

 

The noise did develop over time. My mechanic incorrectly believe it was the A/C compressor 10k miles ago and it is louder now. I think the increase in loudness began after switching to synthetic, but that might be my imagination. There have been no warning lights about oil pressure, but I just ordered a gauge and it will be here in time for the weekend. Following the head gasket repair 5 years ago, there was a valve cover leak. For this is reason, it is possibly that oil was low at some point. Thanks.

 

OK, my $0.02 here....it sounds similar to my 2000 Durango with the 4.7L V-8 when the passenger side timing chain tensioner was failing. It might have already damaged the plastic timing chain guide...that could be the clicking sound. When I did mine, I totally screwed up the first time and (because it was in the timing chain kit) installed a metal backing plate behind the passenger side tensioner. Check for posts under my user name....should be a pic of what I am talking about...if you need me to I think I still have them on my PC...

Best of luck.

Steve

 

From experience, (dropped valve seat on cylinder #2 on my 2000 Durango and #8 on my 2001 Durango) it would not be running that "good" if at all....also should be tripping a check engine light showing a misfire. Hope this helps

Steve

 

Thanks for the response. I pulled the valve cover and it looked normal. The right secondary timing chain could be a little loose, but I am not sure. It is my understanding that the tensioners rely on oil pressure and when I inspected there was no oil pressure. Another mechanic friend I showed it to also believed it was the timing chain. He listened to the noise and recommended trying a Lucas Oil additive. I tried the additive and it didn’t work. Is this something I can live with for a while (just noise) or should I replace soon?