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2010 C4S PDK w/ 135k miles. All routine maintenance items up to date. Did an AX this weekend, and noticed this new sound when I got home. It's a bit deeper and more of a popping sound IRL. I searched the forums and all the other engine noise sound videos are more metallic than this noise (those metallic sounds seem to point to lifters, bearings, bore scoring etc).
In trying to eliminate sources---->Worn Idler Pulleys make lots of noise. Not sure how long you have owned the car but they are usually changed out about 70-80K miles so perhaps time to change out Pulleys & Belt again?
Last edited by groovzilla; 06-10-2024 at 07:56 PM.
Just one data point ... 2010 as well. Poly belt replaced every 60K miles. At 158K now. Still original pulleys and tensioner. Water pump too. And coil packs. Basically original everything on the motor other than spark plugs. The 9A1 motor does not equate to the 997.1. I would change the oil and look for plastic bits that might indicate a chain tensioner. Petza was told in a Jake Raby motor class that the tensioner on the 9A1 can be a problem.
As a matter of curiosity, these motors shouldn't be run hard when cold but shouldn't idle to warm up. What did you do before your AX runs?
I never heard that noise before... odd. It is easy check the tensioner pulley, Google 997.2 belt replacement... you should be able to release the tension on the belt and then spin and handle the pulley. The pulley wheel is on a tensioner.... maybe the tensioner is not applying tension so it may not be the wheel per se. As Wayne noted, your .2 engine is different than a .1, so only follow .2 DIYs.
Just one data point ... 2010 as well. Poly belt replaced every 60K miles. At 158K now. Still original pulleys and tensioner. Water pump too. And coil packs. Basically original everything on the motor other than spark plugs. The 9A1 motor does not equate to the 997.1. I would change the oil and look for plastic bits that might indicate a chain tensioner. Petza was told in a Jake Raby motor class that the tensioner on the 9A1 can be a problem.
As a matter of curiosity, these motors shouldn't be run hard when cold but shouldn't idle to warm up. What did you do before your AX runs?
Great to hear that about the motor; motor longevity and resilience was the main reason I was specifically looking for a 987.2 or a 997.2. I had a 2004 Boxster S and had two engines fail due to oiling issues.
In regards to the autocross, engine wawas warmed up, prior to the first run, and I always leave it idling between runs.
I never heard that noise before... odd. It is easy check the tensioner pulley, Google 997.2 belt replacement... you should be able to release the tension on the belt and then spin and handle the pulley. The pulley wheel is on a tensioner.... maybe the tensioner is not applying tension so it may not be the wheel per se. As Wayne noted, your .2 engine is different than a .1, so only follow .2 DIYs.
thanks Bruce, will look into that. I am taking it to my indie tomorrow so he can take a quick look. He also did not immediately recognize the noise from the video, but AC compressor was a thought.
Great to hear that about the motor; motor longevity and resilience was the main reason I was specifically looking for a 987.2 or a 997.2. I had a 2004 Boxster S and had two engines fail due to oiling issues.
In regards to the autocross, engine wawas warmed up, prior to the first run, and I always leave it idling between runs.
Yea, I had a 2000 Boxster S that had two engines fail also. That is why I chose the new MA1 (.2) engine for my next car. There was no diagnosis of my failures except that the buyer of the car pulled the IMS bearing and it was fine. The first failure, the car sounded like marbles in a plastic box... horrible sound, but back then (at 47K miles under warranty) they crated the engine and sent it back to Germany. The second failure, the engine seized up at around 60MPH on the highway just cruising... running real smooth, then BANG.
This new engine is very good IMO, and Porsche not only designed a new block but upgraded the quality of its parts such as pumps.
I think folks here are pretty sick of me re-posting my story, but hey... I was scarred by the experiences and I know how you feel. I still am listening for any odd noises in this car (and it does)... just do.
Peace
Bruce in Philly (now Atlanta)
Last edited by Bruce In Philly; 06-11-2024 at 10:45 AM.
Swung by my indie yesterday, his stethoscope is cooler than mine:
He didn't specifically recognize the sound, but thought it sounded like the gear mechanism in the throttle body, and localized the source of the sound with the stethoscope. He also pointed out that there is a little bit of a change in the sound / rate of the idle when it makes the noise.
New throttle body kit on it's way from Pelican Parts, will plan on doing an oil change and the TB the weekend after Father's Day weekend.
Bruce In Philly thanks in advance for your TB write up. Between the Pelican Parts videos and that I'm optimistic it shouldn't be more than standard-level frustrating!!
I did the throttle body replacement 2 weeks ago. Took care of the problem. Old TB was pretty dirty. Nothing obviously loose though, no noise when shaken.
There was - as always seems to be the case - an 'oh ****' moment when my torque wrench decided to fail and allowed me to snap the head off one of the bolts securing the throttle body when reinstalling it. Surprisingly little resistance, I was a bit surprised that the bolt was still rotating without builing resistance and then *pop*. Luckily, i had bought a set of replacement bolts so had an extra on hand.
All's well that ends well. Idles smooth as silk now.
06-10-2024 | 03:00 PM
997.2 engine noise - popping
