2006 Cayman S, tiptronic, 70K miles, IMS/RMS completed, all services up to date. I change the oil every 5K with Mobil 1 0/40. This noise is at start up goes away as the engine warms. Tempo or timing of the knock doesn't change with RPM, if anything it makes it quieter after pressing the accelerator. Video of noise attached. Any ideas?

 

video didn't work. Are you driving the car daily or does it sit for periods of time?

 

Hello Steve, Thank you for the reply. It is a daily driver. I think I fixed the link to the video.

 

Hard to hear anything definitive. But have you changed your serpentine belt? I think it has to be changed every 5 years regardless of mileage, or every 40k miles if memory serves. I think your belt was making more noise than the motor internals.

 

Hello Steve, Thank you for the quick reply. I didn't think to check that, is there more than one belt? I know it had a belt changed at its 60K service. I'll go find my book on it and check that work order. I see what you mean, it is hard to hear over the computer speaker when I play it back. It just doesn't capture the tone of the sound.

I LOVE this car, but it does keep me worried most of the time. It has never had any problems since I've owned it so I dont have any concrete reason to worry. I know that statistically the percentages of IMS, or Oil starvation, or d chunk is realtively low. It's just that with three things to look out for I feel like I"m constantly listening to my engine looking for anything unusual. Sometimes it makes it difficult to enjoy the car. I've put so much money into it I feel like it would be a waste to trade it in, even knowing about the possible failures. Wouldn't these engines become more and more likely to have one of three major problems with age and mileage?

Oh yeah and don't forget bore scoring.

 

The best position to listen to a suspected engine noise with these cars is from underneath the car with the car on a lift.

You can narrow down from where the noise is coming from and from this then make a reasonable guess as to what is going on.

If the noise is not in sync with engine RPMs that suggests the noise is not necessarily internal to the engine. With a manual transmission car gear box "rattle" or clutch disc "rattle" is a possibility. With a Tip though... almost certainly not a possibility. What does the noise do/sound like when you shift the Tip into D or R or even just out of P into N?

One thing I have done in the past when a new/strange noise appeared was to remove the serpentine belt -- noting its direction of rotation and orientation so I could install the belt back the same way it was before I removed it -- then start the engine and let it idle just long enough to confirm the noise was still present or was gone.

In the case of my Boxster when I did this the noise was gone. Further investigation found a bit of play at the water pump pulley/shaft while none of the other accessory drives exhibited any play. Also, the belt's inner edge was sharp while the other edge was dull just like the both edges on the old belt which I had handy. The sharp edge told me the belt was rubbing and it was rubbing because of an alignment issue and the issue was due to bearing play in the water pump. I buttoned the car up and had the car flat bedded to a dealer and had the water pump and T-stat replaced. Noise gone.

Unless you are prepared to get your hands dirty my advice is to avoid running the engine any and instead get the car in the hands of a professional tech who will listen to the noise and make a diagnosis as to where the noise is coming from. From this then he can advise you as to what the next step is.

Be careful. No noisy Boxster/Cayman (996/997/etc) engine ever got better with more engine run time.

 

Hello Macster, Thank you for your help. I will do that and let you guys know what it is. These are really good questions, I didn't think to check if it makes the sound in gear. I know so far I've only heard it while in park idling. It seems like the sound dissapears when I put it into gear, but I can't tell for sure. I'll take it to my indy and figure this out. Thank guys, I really appreciate your help and knowledge.

 

Ok so I took my car to my Mechanic yesterday and dropped her off. They checked everything, I dropped it off a day early so they could hear the cold start. They did a wonderful job going through and checking everything. No pulley noise, no knocking, no ticking. Scanned it and drove and tested under different conditions, and of course scoped the pulleys and different parts of the drive train. The sound that I'm hearing is actually injector and regular valve noise. These guys are Porsche and BMW gurus, they have over 100 years experience between the eight of them. They are PCA guys also, so is the owner.

A couple of years ago my doctor told me that this may happen that I may hear sounds that no one else will hear. They call it a Auditory Processing Disorder that my have been caused by a work related injury. Apparently the sounds from between my inner ear and brain are screwed up and sometimes I can't speak or hear well. They also diagnosed me with Tinnitus so that could be contributing to the sounds I think I hear.

Thank you everyone. I am also going to switch from the Mobil 1 0-40 to Motul. I love this car, it makes me feel better every time I drive it. CHEERS!!

 

If you want to switch to an approved 5w-40 oil that's up to you. Frankly in Tacoma with its climate on the cool side I'd stick with 0w-40 year 'round.

My hearing's failing. And I have tinnitus too. I am aware that with impaired hearing one can hear things that may be all in one's head. Seems the brain fills in the gaps the audio sensory system leaves in the signal to the brain.

Also, humans are quite adept at pattern recognition. Both visual and audio pattern recognition. It is what helped our ancestors, our very early ancestors, spot a predator lion or tiger in the tall grass, brush or bushes, or recognize the sounds of something hungry prowling around in the dark.

But it can also have us hearing noises from our Porsche cars that ain't really anything to worry about.

 

I just wanted to say thanks to everyone for taking the time to help me out. I learned a lot from this experience. Just so grateful its not a scored cylinder. The motul was a suggestion by my mechanic. I was doing my own oil changes, but I think I'll have my mechanic do it from now on. Thank you for all your help and insight everyone!!