I'm hearing a rattling noise if I accelerate while cold. Sounds like a fairly unsettling rattling.

Listen to the two attached clips. (updated)

COLD (rattle): http://vocaroo.com/i/s04VR5b1jnkY

WARM (no rattle): http://vocaroo.com/i/s1zhzujj5XUv

The sounds is dramatically reduced as the car warms up, but is still there. Any thoughts? Normal/sign of age/urgent fix?

Car is a 2005 Boxster with about 50,000 miles.

 

With the car cold, put the back end up on jack stands and climb under it with a rubber mallet. Tap gently around the engine bay. My guess is heat shields are loose around the muffler/cats.

 

A two second clip? Gee you think you can spare it?

Sorry. No lunch yet. Sitting a shopping mall lobby waiting for a call to get my Macbook Pro keyboard looked at and I'm getting short tempered.

What I could hear over the din here sounds like you need a professional experienced Porsche tech to give a listen. In the meantime my advice is to err on the side of caution and avoid running the engine any. If the engine sick -- just saying -- it might be salvagable but if you run the engine any more you can ruin it and then the cost of putting the car back on the road goes up.

 

Thanks for the replies. Here is a longer clip, accelerating from from about 2k RPM to about 2.7k RPM, slowing down, then doing it again.

COLD (rattle): http://vocaroo.com/i/s04VR5b1jnkY

WARM (no rattle): http://vocaroo.com/i/s1zhzujj5XUv

The sound is very loud when cold, much quieter when warm.

I can hear the same vibrating sound at all times now, but perhaps it is just an earworm.

I'll put the car up on jack stands later this month and start tapping, thanks for the suggestion JG.

I'd prefer to DIY as much as possible for now, both to save money and get experience. But if the consensus here is that this is both potentially seriouis above my pay grade I'll take it in.

 

I can't really offer an opinion based on the longer clips. I hear a difference between the two clips but what it means I can't say with any certainty.

Do not attempt to make longer clips. Without knowing the source of the noise more engine run time could only make things worse.

No Porsche engine ever got less noisy with more running.

My advice/recommendation in these situations is to err on the side of caution and get the car professionally diagnosed.

DIY is ok for things like oil/filter services, brake pad/rotor R&R, brake/clutch fluid flushes/bleeds, maybe even clutch R&R jobs, water pump, coolant tank replacement but for suspected internal engine problems unless you have considerable experience dealing with these are best left to a professional.

If you want to do this yourself, and I do not advise it, you need to identify the location of the noise.

Before you put the car in the air, one thing you can do is remove the oil filter housing and dump the oil and filter element out into a *clean* drain pan and check for any debris.

What you find, or don't find, plays a big role in what your next step would be.

If the oil and filter is free of debris it might be safe to proceed. If there is debris you are finished, unless your desire to doing it yourself extends to dropping the engine and disassembly of same to address the source of the debris.

To identify the location of the noise, the most likely source of the noise, this is best done with the engine running in such a way to make the noise and with you under the car listening with a mechanic's stethoscope. You have to be very careful. Get a body part caught in the serpentine belt or touch a hot exhaust pipe and you'll remember the experience a long long time.

Knowing from where the noise is coming from goes a long way in helping you then know what is causing the noise.

 

What others are implying, but I have not seen stated, it that it might be the dreaded Intermediate Shaft Bearing starting to go. This can be a catastrophic failure if it is not caught early.

Macster has a very good suggestion to check the oil filter. Every year when I changed my oil on my 02 S, I would cut the paper element out of the oil filter using a case cutter, then stretch out the paper and look for metallic debris on it. In my case, it was always clean, but it is a very good way to see if you are getting metallic bearing bits on the filter which is a strong indicatation that the IMS bearing is starting to die.

 

Thanks everyone for your help. Here is what I did to check, may it help future users of the forum.

I ended up lifting the car in the air and trying to find the cause with a mechanics stethoscope. I didn't have much luck - I'm getting a bit of lifter tick from what seems to the the second right cylinder (different from the sound I'm after), but I can't reproduce the rattling sound without the car on the ground so it was hard to diagnose.

I checked the used oil I had on hand and nearly had a heart attack as it was filled with little black shavings. After close examination, I was relieved to see that those shavings were all black plastic and had come from the Walmart oil pan that I'd used. So I was safe.

I banged around with a rubber mallet looking for loose parts and everything seemed solid except one of the cats. I tightening that and all of the other bolts on the exhaust system and heat shielding, problem was still there (although the car did sound a bit better, this helped vibration and I'd suggest it to people who have their cars in the air).

I removed the accessory belt and briefly ran the car. The problem was still there. That told me the problem wasn't the water pump (which was my other guess).

I'd changed the sparkplugs already, as I'd been worried it was a loose/misfiring spark plug.



So I gave in and took the car into a mechanic. They couldn't hear the noise, but they got a fuel system pressure code during their testing.

The issue was a cracked gasket on the fuel cap. Replacing that seems to have fixed the noise (fingers crossed). IE: The rattling I heard was due to pressure escaping from the EVAP system when I accelerated.

 

Wow! Never could have diagnosed that one over the internet!

 

my 2006 Boxster S has done the clacking sound between 2500-3000 rpm for years. I have had it checked under factory warranty and by an independent mechanic later as well. The only thing I heard from them is that it "could" be a pressure relief valve. Nothing to worry about they say. It is louder when cold and only noticeable in first and maybe second gear when the engine is under more load. Happens both accelerating and decelerating.