Bitsa

997 owners !

Who has a really nasty engine rattle/knocking noise when the engine starts up from cold ?

Seems to be okay once the oil gets around the engine (after about 30seconds)... but sounds like the valves are going to pop thru the engine housing or the Exhaust is going to drop off !

Dealer & PCNA Rep. seems to think it normal/ok... but I haven't heard another 997 do it yet !

Anyone else have this with their 997 ?

Seems to be a 997 problem... I've had three 996's and three 993's previously... no such problems with them !

Pete@Stratmosphere

I heard something funny firing up a 997 S before PDI at the dealer. Sales guy and I looked at each other like..."what's that?!" and then it stopped. Can't say I know what it was. -Pete

Bitsa

Yeh, it goes away after a little while...

Depends how long it been sitting there for ??

If I leave it overnight... like 10hours plus... it's worse !

Guess most/all the oil settles back into the sump... drains off the engine parts ?

Car runs okay.... whooosh ! but still worries me tho... oooo errrr !

Pete@Stratmosphere

Won't cancel my order ;-) Pretty funky. We will see if the new car does it too. -P

SkipSauls

Mine makes a rumbly/growly sound on startup, but I like it as it reminds me of the sound that the air-cooled 911s make on startup. I didn't think anything of it.

jcnesq

Mine, like Skip's, makes a (nice) rumbly/growly sound on startup, but that's basically an exhaust sound. I take it yours is some kind of knocking (tapping?) sound from the engine itself?

Bitsa

Wish it did make a nice rumble like an aircooled !

I've had 3 new 993's... it don't sound as funky as an aircooled... thats what worries me !

I'd be happy with a funky rumble :-)

Sounds like someoone banging a wrench around in an old fridge !

Don't get me wrong.. I'm Porsche thru and thru... this is my 12th Porsche in the last 17 yrs... I'm very used to their funky idiosyncrasies, but this just dont sound right to me...

Once I've heard a few more 997's doing it... I'd accept it !

For now... I'm still worried :-(

Viken

If the noise persisted, it wouldn't be ok. But, it is, in this case. It's coming from the hydraulic valve lifters. And, you said it yourself, the noise goes away once oil reaches the heads. It should happen when the car had been sitting for a while (2 days or more). My 996 GT3 does it, so did my previous 993. Both cars were driven on weekends only.

infestation

My car is loud--a rumble sort of loud--but no unusual or strange noises...

Loving it more and more every day.

nyca

30 seconds seems like a long time, I'm no Porsche engine expert of course. 10 seconds would be more like it. How many oil pickups in this motor? It should start slurping that Mobil One pretty fast. are you sure its not an exhaust rattle?

Bitsa

Hi guys... thanks for all the posts to my question

VIKEN - I used to park up my 996's and 993's for days too... but this is a very different noise... more a knocking noise than ticking like hydralic lifters... Happens after only 8-10 hrs and lasts longer the longer it's left standing (16hrs of no-operation = 1 or 2 mins of knocking )

NYCA - It does sound like a exhaust rattle a little, but its not there after the exhaust cools down.. more like I have to wait for the engine to get drained of oil before the noise returns..

Lets hope a few more 997 S owners post that they have similar concerns... then I'll feel a little better about it :-)

jcnesq

Ian - like you, I've owned many Porsches before the 997S. The 997S engine is fundamentally no different than those that came before. No "unusual" noises from my 997S. Hope they can check it quick for you and diagnose it properly. If you have any trouble with Rusnak, I can call the head mechanic downtown - great and knowledgeable guy - and put you in touch with him.

Carrera GT

This is a noise peculiar to flat engines and, for whatever reason, I don't know for a fact, it has become pronounced in the 997. It was evident in the 996, but the "knock/rattle" complaint is apparently evident in most if not all 997's. Bizarre. It's not a valve or lifter noise because it happens during cold startups and during hot startups immediately after the engine has shut down, plus it simply does not sound like hydraulic lifter noise (if you've owned or worked on 928's, you know that noise from "wet" Porsche engines ...

For all the 996 cars and the grand total of three 997 cars I've heard or driven, I've heard this noise in all three 997's (two "S" and one Carrera) and maybe a handful of 996 cars (but only one customer, someone about to go out of warranty, who has brought it to us to see if it had warranty issues) so I can't jump to conclusions. I'd say Porsche still has RMS issues for the 997, let's hope there's no other gremlin in the 997 engine bay.

MrClifton

I think it's the forged pistons rattling on start up. I've had brand new engines in Chevy's and race Honda motorcycles that rattle for a while when cold. The pistons are not round when cold. They become round when warm.

NJ-GT

That noise is called "Air Pump". My GT3 has that as well.

The Air Pump works injecting air (oxygen) on the exhaust when the car is cold to reduce emissions. It sounds like an engine with worn out connecting rod bearings.

It last about 30 seconds. When my car has been parked for days, the sound is even louder.