This has been a frustrating year so far for my MCs. I had to replace the valve cover, I slid into a curb during an ice storm and had to have the lower control arm on the passenger side replaced, hit a pothole on the same side and dented the rim, and I have a coolant leak, I think from the thermostat housing. Just waiting for the parts to arrive.

Today, after driving around almost all day, I had a very loud whirring sound start up that changes pitch with the RPM. I initially thought it was the wheel bearing, but after some driving in circles, the sound didn't change at all. When I was driving back, I realized it was RPM, not speed related. It's coming from the right hand side of the engine, and I imagine it's probably a bearing on something going bad, but I have no idea what.

I'm at 56k miles. What is located on that side that is likely to go bad? Any tests I can do to narrow it down?Could it just be the belt?

 

I had a whirring noise like that, I just had my belt tensioner replaced to correct it.

Unfortunately it didn't fix it. The tech did say it sounded like a bearing going bad after listening to it with a stethoscope. I wonder if it was a different bearing, or it it was a wrong diagnosis altogether. For me, it only gets noisy after the car is warmed up - I have to drive for at least 20km before it presents itself - and is most noticeable at about 3K RPM.

 

I'll see tomorrow, but I let it sit for about an hour and a half before trying to figure out where it was coming from and it was making the sound as soon as I started moving again. It's really strange in that it isn't as loud whenever I'm in neutral, but it is definitely still there, so I'm certain that it isn't the wheel bearing or somewhere along the drivetrain.

 

Well, I changed the belt, because it was pretty cracked, but all the pulleys seemed fine. Started her up and it still was making the sound. I tried to locate the sound better, since I had someone to help me, and it sounds like it's coming from the front, near the supercharger. I pulled the turbo inlet tube and found over half of the gasket on the turbo side missing. I'm guessing that this was the cause of the problem, and just ordered the line.

The thing I'm worried about now is, if the missing part of the gasket got sucked into the turbo, what kind of damage am I looking at? I didn't get any cel codes or other errors, and I didn't notice a loss of power. I did just notice, however, that the corners of the blades are all chipped off. I'm really worried about this.

 

Are the blades actually chipped, as in uneven? I'm not sure about in the MCS, but some blades are made with odd contours around the corners sometimes.

If the blades are in fact chipped, I'd look into replacing the turbo and maybe having a mechanic check the cylinder walls and such with a borescope. Or at least doing a compression test to see if there might be any damage to the sealing surfaces.

On the other hand, I wouldn't expect plastic to do a whole lot of damage to the metal internal bits, and would think the odds are reasonable that the blades could escape without major damage.

When in doubt, show the bits to a pro and ask for advice...

 

Does it sound like crickets chirping? The older plastic water pumps and pump pulleys tend to make whirling noises. The old style valve covers, not the megaplast ones, are prone to splitting open along the rear seam. They cause a whistle along with other rough running symptoms. Hope that helps

 

This sounds EXACTLY like what I've been hearing. Would it make sense that it only manifests after the car has had a chance to warm up for awhile? If you could give me any other information on these parts/failures I would really appreciate it!

 

Do you still have the plastic water pump? Sometimes the rubber on the water pump pulley becomes pitted and causes the noise. If you already had the friction wheel/tensioner replaced i'd bet bet its water pump related.

 

You can buy just the pulley.
https://www.rockauto.com/en/catalog/...r+pulley,10346