997_rich

I've got an issue with something near the belts on the engine. It seems to be coming from the top of the engine and belt related. It sounds like a pulsing wearing part. I've replaced all 3 idler pulleys and the belt. The pulsing noise is loud and audible from the cabin of the auto. The pulsing is in time with the engine RPM and is happening with the AC on or off. The water pump was replaced ~10k miles ago and there is no leaking. The power steering fluid is full. nothing is rubbing on the belt at all.

It sounds like it's either the alternator bearing going bad (but the tone isn't squealing, its more of a mid range). Or it sounds like the power steering pump going bad because it has the pulsing sound i'd normally associate with the power steering, but the power steering has never been run dry and works perfectly.

Any thoughts or advice?

Thanks in advance

USMC_DS1

Car looks like a 997.1 from your avatar. But let's start with which car you have, what year is it and how many miles? BTW, if it's a 997.1 S then it should have two idler and one tensioning pulley. Are these the three pulleys you replaced?

BED997

Also, does it happen when cold and go away when warm? Happen all the time?

Edgy01

Did it make the sounds before the belt replacement? Am assuming you replaced the belt because of that, as well as the idler pulleys and tensioning pulley. Did you see any wear on the pulleys?

997_rich

right 997.1, 3.6 liter. I replaced the yellow and green pulleys and the belt because the noise was very faint. Yes, i saw wear on the pulleys that i replaced. all pulleys move freely and make no noise when the belt is off. I can't seem to feel any play in any of the pulley or accessory bearings.

the noise has been getting steadily louder for ~1k miles. I thought it was one of the idlers/tensioner but no luck.

The AC (turqoise) seems to be OK because the noise is the same with the ac clutch engaged or no.

At the moment I'm feeling like the PS pump is it. it sounds almost like the innards of a PS pump failing. Like a pulsing wearing groan. It's just hard for me to believe that it would fail at 90k with no abuse and consistent driving (it's my daily driver).

USMC_DS1

The WP is known to go out at 40-50k. Some here have had to replace must sooner. There are DIYs posted on the DIY sticky which will help with that job. I replaced my WP preemtively at 52k.

997_rich

Here's one other thought... The tensioner arm seems quite strong on this car. I used a wrench with a breaker bar attached to fold it back to change the belt. Does that sound right? Usually there's no need for a breaker bar to do this.

Maybe the spring is munged up and causing too much force on the belt. the pulsing sounds almost like a bad section of the belt but I can't see where the belt is trashed. It's been 500 miles since I did the idlers and the belt and I thought that had fixed it. Now the sound is back and getting louder.

Maybe I'll try another belt and see if there's a difference.

997_rich

I just did the WP not 7k ago... and it sounds like it's coming from the top of the engine.. I'll check it again. It spins freely with no play when the belt is off.

USMC_DS1

I did this initially and over torqued the tensioner. I had to torque it back to tighten the tensioner enough to get it to work properly. I'm curious about your tensioner replacement. I had considered doing this as well but solved my issue with a shorty open box wrench to retorque the tensioner. Did you have to remove the entire assembly? Was it a fairly easy job? I tend to agree with you that this may be the suspect area to investigate/troubleshoot. BTW, you don't need to over torque the tensioner to slip on the s-belt. For example, sliding the belt around the lower yellow idler provides for enough free play that you don't have to crank the breaker bar past the tensioners point of free play. GL and let us know what you find. Would be great to see a DIY of the tensioner removal/install process if you work on that again.

Money Pit 951

Get the largest longest screw driver you have and put the spade end on what you think is making the noise. Cut your hands at the end of the handle and put it to your ear. Moving it to different area - the alt, PS pump, etc and you'll be able to hear where your noise is coming from.

Edgy01

When I've replaced one of these in the past we needed a long handled tool to overcome the tension from the tensioner pulley. That tension is fixed--not adjustable.

997_rich

yes- the tension is fixed- driven by the spring. No adjustment. I don't know what the spring looks like I was just wondering if it was rusty or something preventing it from moving freely.

Anyway, I didn't replace the the tension arm, just the tension arm pulley.

I tried the screw driver trick, using it like a stethoscope... it's tough to tell.

I tried to buy a belt at the dealer. they wanted 80 dollars and they don't even have it in stock. No thanks. I ordered it from suncoast for $45 shipped arriving on monday. we'll see if that makes a difference.

Thanks

997_rich

I replaced the old (2 mos. old) belt and the new belt fixed the problem. The old belt looks fine in every way so I'm not sure what's up.

I also rechecked all of the pulleys. they all seem fine. the one that I am questioning is the AC clutch. It has about 0.5mm endplay. The endplay is in the clutch assembly not in the shaft. Does that seem normal? Maybe I have a new ac clutch in my future.

Thanks.