Could use a bit of input here.

Upfront I have been the only owner of this vehicle and oversee all the work done to it, or have done it myself So, we are not bound by what might have been, only what is. I don't drive the car much and it has 190,000+ miles on it.

Last year the car developed this chirp that happened every now and again, and Only once the car had heated up for say an hour or so of driving. It had no pattern other than that. during the winter no issues.

As far as front end of the engine, only two belt driven devices have not been replaced, the AC compressor and the water pump. In the last 5,000 - 10,000 miles I have replaced all the idlers, tensioner, power steering pump, SC bearing, and alternator. Belt is new.

Now this its hot in the NE it takes about 10 minutes before the noise starts in. Revving the engine turns there random squeaks and chirps into a full on squeal that get louder too.

Here is the noise in action - Video

I am thinking that the water pump might be in question at this point in the car's life. video water pump

 

I would unplug the radiator cooling fan and remove out of the way since it is so easy, then use a mechanics stethoscope or a 3' or so length of rubber water hose held up to your ear, and VERY CAREFULLY check all pulleys, pumps,etc..

 

Been there done that. Most of the parts on the front are relatively new and spin freely. Just replaced the alternator for bearing noise and roughness. Noises were there pre and post. at first we thought that was the culprit using a scope to listen.

 

SC pulley clutch slipping?
SC bearing?
SC lacking oil due to a leak?

 

No slipping on the clutch, new Sc bearing installed less than 1000 miles ago and spins freely, SC oil was redone 10000 miles ago no leaks.

 

I was referring to a bearing in the SC not the SC clutch bearing which only spins at low engine revs, it does not rotate when the SC is running.
What about the Intercooler pump? It does not spin faster with the engine revs but .....
I tend to think of the water pump, has it ever been changed?
Could be the clutch bearing on the AC pump.

 

Perhaps you need to "Been there done that" one more time, since apparently everything that you replaced wasn't the problem unfortunately. I've always had pretty good luck with the water hose stethoscope, but I know that pinpointing problem noises with engine running can often be difficult. You say you don't drive it much, but 190k miles is a lot of miles. And at 14 years old, perhaps it is your water pump as you suggested in your first post.

 

You mentionned you replaced many parts driven by the belt. it could be an idea to verify pulleys alignment. My 1989 Dodge Daytona have a sound like that before and i removed the air conditionner belt and noise stop. You can made a test to eard if the noise came from belt. Using a "windex" type spray bottle filled with water, run motor until noise begin and spray a bruin of water on belt. if noise stop and came back after a couple of seconds it is surely a bad or misaligned belt / pulley.

 

Have you checked water pump pulley for play with the belt off?

 

yes, the link to the video is in the original post. There appears to be a bit of play (maybe 5mm in any direction) along with a slight clunk.

My reasons for asking is nothing about this is consistent, one day it will chirp with the AC on and won't with the ac off (while parked), some days if I accelerate fast for the AC off I will get a short 1 second squeal and with the AC a much louder screech of 3 seconds while parked or in drive. Other times it is like what is shown in the video parked with the ac on or off.

 

The replacement of things to this point had nothing to do with the noise, rather items that required replacement over time.

Ordered up a water pump and got some tubing to help pinpoint it (not to mention using a bit of audio trickery as well) I just wish it was a bit more consistent in its presentation. That in itself is driving me to think bearing vs the squeak of a belt.

 

5 mm in any direction? This is a German made car so nothing wobbles 5 mm. ��
5 mm is .20”, if you have your units correct then this pump is toast.

 

Yea 5mm total 2.5 one way or another. The play is one thing and given what I can see on the water pump pulley, it looks to move some. The give away here is the knocking which to me suggests what ever is on the other side is hitting something and maybe as things heat up (I don't get any noise when cold) it is rubbing enough to cause things to slip.

I should see a new pump arrive from Gates next week and then get over to the shop and swap it over.

 

Since you have to drain it down anyway, get a gallon of Zerex G05 coolant and a gallon or 2 of distilled water and do a cooling system flush also.

 

The good the bad and the ugly.

The good news is that after chasing this issue down by working from the cheap parts to the most expensive, I now have new bearings or pulleys in all locations that make for a smooth running engine.

The bad news is that the most expensive part was indeed the culprit.

After 192,000 miles the harmonic balancer separated and was moving a bit causing the noise. It was tight enough that it held together, and from the outside it looked good, on the back side there were some cracks and places where the rubber was not sitting correctly.

 

I wish I saw your post earlier, I would have told you it was the harmonic balancer from the start. Im at 199k mine started making that noise around 190k or so and like you I literally replaced all pulleys except the balancer and it was still making the noise. I replaced the balancer and noise was gone. On the positive all the other pulleys are good and new.

 

We all learn a great deal when we hit those big mileage numbers. While I did replace a bunch of stuff, parts for this car can be cheap if you look around. What I can't believe is that the balancer held together for more than a year without exploding.

Upside is that the engine runs a great deal smoother than before.