997 Clatter on start up

[Hogster]

Hi everyone,

I have a Gen 2 997 which now clatters on start up. Weirdly, it sounds like my wife's VW Golf TSI engine which every now and then makes a tractor like noise on start up. I think it has something to do with the tensioners, not enough oil pressure etc, but this seems to happen after I have had a long drive, and then started the car up a couple of hours later, ie when the engine is still warm.

Anyone else had any experiences with this, is it just one of those quirks ie put up or shut up or can it be resolved? It is under Porsche Warranty.....

Thanks

[NBTBRV8]

My 997.2 GT3 does this and I cringe everytime I hear it. More often than not when it does it, it blows a puff of smoke too.

[Rockster]

First it is always best to have a professional give a listen. He is the only one at the car and can best assess what if anything the noise means.

Next how's the oil? How many miles? Lots of short trips on the oil? An engine can get noisier as the oil collects miles because it also collects unburned gasoline and water. Both work to thin the oil and the engine makes a bit more racket at least at start up.

I do not think you are hearing noise related to chain tensioners though the chains can make a bit of noise. But this noise is rather distinct, like a link chain being dragged over a piece of lumber.

What I think you are hearing is the extra clatter the VarioCam Plus hardware makes, specifically the hardware that switches to and supports intake low lift.

The default is high lift. So as the engine cranks and begins to run it starts out with high lift. Then once the engine is running and obtains some rpm threshold and oil pressure has stabilized and reached some minimum pressure -- which takes more time to type in than it takes to happen -- the DME switches to low lift. The noise makes up at least some of the noise you are hearing. The noise is helped by the hot oil.

At cold start with cold oil the thick/cold oil acts to dampen the noise and the switch over is well, less noisy.

Of course I can't hear the noise but I do not think you are hearing anything out of the ordinary. That you report no other symptoms helps me say this. But as I started out with have the engine listened to by a professional one trained on these engines and experienced with them.

[Helicopter123]

Hogster said:

Hi everyone,

I have a Gen 2 997 which now clatters on start up. Weirdly, it sounds like my wife's VW Golf TSI engine which every now and then makes a tractor like noise on start up. I think it has something to do with the tensioners, not enough oil pressure etc, but this seems to happen after I have had a long drive, and then started the car up a couple of hours later, ie when the engine is still warm.

Anyone else had any experiences with this, is it just one of those quirks ie put up or shut up or can it be resolved? It is under Porsche Warranty.....

Thanks

Hogster - is yours a Turbo?

[Hogster]

Thanks, everyone

Yes, this is a turbo.

My other turbo didn't do this at all, neither did my 4s.

I understand the GT3's suffered from it, but the point remains, normal or not, should it really be happening to such an expensive car and can it be fixed? Great car, but some of the enjoyment is hammered right at the start when it turns over!!

[Hogster]

Rockster said:

First it is always best to have a professional give a listen. He is the only one at the car and can best assess what if anything the noise means.

Next how's the oil? How many miles? Lots of short trips on the oil? An engine can get noisier as the oil collects miles because it also collects unburned gasoline and water. Both work to thin the oil and the engine makes a bit more racket at least at start up.

I do not think you are hearing noise related to chain tensioners though the chains can make a bit of noise. But this noise is rather distinct, like a link chain being dragged over a piece of lumber.

What I think you are hearing is the extra clatter the VarioCam Plus hardware makes, specifically the hardware that switches to and supports intake low lift.

The default is high lift. So as the engine cranks and begins to run it starts out with high lift. Then once the engine is running and obtains some rpm threshold and oil pressure has stabilized and reached some minimum pressure -- which takes more time to type in than it takes to happen -- the DME switches to low lift. The noise makes up at least some of the noise you are hearing. The noise is helped by the hot oil.

At cold start with cold oil the thick/cold oil acts to dampen the noise and the switch over is well, less noisy.

Of course I can't hear the noise but I do not think you are hearing anything out of the ordinary. That you report no other symptoms helps me say this. But as I started out with have the engine listened to by a professional one trained on these engines and experienced with them.

Thanks for this detailed response. The car is 2 years old, 16000 on the clock and I only bought it on Friday. One previous owner from new who lived outside of London. Can only deduce he wasn't doing too many short trips to get 16k in under 2 years.

What you say makes sense though; my first few drives were spirited, and I noticed the oil level lose a bar probably due to evaporation etc. it had been serviced just before I bought it, but don't know about oil. Turbo S.

[arcamalpha]

It certainly gives an uneasy feeling when it happens on my GT3.

However, I know know the circumstances when it happens and it sounds the same eachtime so nothing to worry about.

If the noise changes I'd be worried.

My advice would be to listen carefuly and only worry if it changes.

[Hogster]

arcamalpha said:

It certainly gives an uneasy feeling when it happens on my GT3.

However, I know know the circumstances when it happens and it sounds the same eachtime so nothing to worry about.

If the noise changes I'd be worried.

My advice would be to listen carefuly and only worry if it changes.

Thanks, I don't believe it is harmful, so I'm not panicking, but it is disheartening to hear such an expensive car sound like that. John Deere sounds better!

[Magic919]

You should book the Porsche Experience Centre and take out a couple of their GT3s, take the morning slot. They really sound like a bag of nails. Makes my Gen 2 Carrera sound like a Rolls by comparison. However, nobody would buy a modern 911 because it sounds great at tickover. Wait until you get a cloud of smoke too.

[Hogster]

Magic919 said:

You should book the Porsche Experience Centre and take out a couple of their GT3s, take the morning slot. They really sound like a bag of nails. Makes my Gen 2 Carrera sound like a Rolls by comparison. However, nobody would buy a modern 911 because it sounds great at tickover. Wait until you get a cloud of smoke too.

Yes, a friend has the GT3 and I know what you are talking about. I can handle some smoke etc but the noise on a car like this, which is supposed to be GT when you want it and hardcore at other times, seems a little off key. It's not normal, unless people settle for it. I just havent heard other DFI Turbo users complain of the same sound.........

[Martian O]

Magic919 said:

....Wait until you get a cloud of smoke too.

My gen1 Turbo used to do this every one in fifty starts but I haven't noticed it at all since switching to Millers Nanodrive 5W/40.

[Rockster]

Hogster said:

Thanks for this detailed response. The car is 2 years old, 16000 on the clock and I only bought it on Friday. One previous owner from new who lived outside of London. Can only deduce he wasn't doing too many short trips to get 16k in under 2 years.

What you say makes sense though; my first few drives were spirited, and I noticed the oil level lose a bar probably due to evaporation etc. it had been serviced just before I bought it, but don't know about oil. Turbo S.

8K miles per year is not big miles. (I've done 5K miles in a week in my Turbo.) But it is in the ballpark of the number of miles Porsche assumes these cars are used: Roughly 6K to 9K miles per year, though daily drivers can rack up more miles.

My Turbo (996) engine is a bit ragged upon cold start and for a while after. It was with 10K miles on it when I bought it used and it is with 109K miles on it.

This is normal. It arises from the DME feeding -- on purpose -- the engine too much gasoline (along with extra air via the secondary air injection system) which is passed on to the converters where the fuel is burned to heat the converters up quicker. If one listens carefully he can hear some backfires in the exhaust which is a sign the engine's running richer than ideal.

The engine really changes personality as it gets a bit of heat though -- well, as soon as the converters get hot enough to work -- and the DME drops the rpms to near normal concurrent with leaning out the mixture.

[Hogster]

Rockster said:

8K miles per year is not big miles. (I've done 5K miles in a week in my Turbo.) But it is in the ballpark of the number of miles Porsche assumes these cars are used: Roughly 6K to 9K miles per year, though daily drivers can rack up more miles.

My Turbo (996) engine is a bit ragged upon cold start and for a while after. It was with 10K miles on it when I bought it used and it is with 109K miles on it.

This is normal. It arises from the DME feeding -- on purpose -- the engine too much gasoline (along with extra air via the secondary air injection system) which is passed on to the converters where the fuel is burned to heat the converters up quicker. If one listens carefully he can hear some backfires in the exhaust which is a sign the engine's running richer than ideal.

The engine really changes personality as it gets a bit of heat though -- well, as soon as the converters get hot enough to work -- and the DME drops the rpms to near normal concurrent with leaning out the mixture.

Thanks, Rockster.

I think I understand what you are talking about, and it happened with my Gen 1 car, ie sounded a lot louder on start up, as do most cars. I only recently changed from a Gen 2 Turbo to a Turbo S and the last one didn't make this tractor like noise for a few seconds, so I can only assume it isn't normal......... That or my last car was a happy freak of nature. I still haven't heard any other DFI Turbo users hearing the same racket..........

I will let Porscbe inspect.

Thanks again

[stank101]

might be a long shot but, did you sort this out in the end?
I just bought a 10’ 997.2 turbo which is doing the exact same. Has OPC warranty for another 18 months, was recently sold by Porsche wilmslow.

Sound gets abit embarrassing in polluted areas... Porsche East London didn’t pick up on it and I personally think they didn’t bother.

[nebpor]

Rockster said:

My Turbo (996) engine is a bit ragged upon cold start and for a while after. It was with 10K miles on it when I bought it used and it is with 109K miles on it.

This is normal. It arises from the DME feeding -- on purpose -- the engine too much gasoline (along with extra air via the secondary air injection system) which is passed on to the converters where the fuel is burned to heat the converters up quicker. If one listens carefully he can hear some backfires in the exhaust which is a sign the engine's running richer than ideal.

The engine really changes personality as it gets a bit of heat though -- well, as soon as the converters get hot enough to work -- and the DME drops the rpms to near normal concurrent with leaning out the mixture.

Hah, as a new 996 turbo owner this explains it brilliantly - I was just telling a friend how the engine really changes in character as it warms, it's a lumpy dog when it's cold ... I love that feeling of it coming alive!

[7litrebig]

stank101 said:

might be a long shot but, did you sort this out in the end?
I just bought a 10’ 997.2 turbo which is doing the exact same. Has OPC warranty for another 18 months, was recently sold by Porsche wilmslow.

Sound gets abit embarrassing in polluted areas... Porsche East London didn’t pick up on it and I personally think they didn’t bother.

Reviving an old thread.... I've had 2 different 997.2 turbos over the last 10 years... with ownership spanning 5k to 45k miles so far. Both made/make this "death rattle" noise - "that's normal sir" was the OPC reply a few years ago on my first one... so I just put it in the memory bank as a no cost "feature"

[Planetstank]

Oop. Hate to revive old threads but
^ at the time when I had my old turbo, Porsche eventually replaced the chain under warranty (few months after that comment^), and it went away completely. My brothers 997 turbo s also has the noise but opc still trying to play the “it’s normal” game. My uncle also has this noise on his 991 turbo and was also told it’s normal. Clearly is an issue with the timing chains maybe stretching/wearing over time?

But, yes a replacement chain solves that death rattle noise