benoitroussel

I have a 2004 996 TT x50 and was driving it a bit aggressively the other day (nothing excessive either, but the engine was certainly not cold) and noticed a high pitched noise coming from the engine when I eventually slowed down (the noise of the engine was covering that high pitched noise when I was driving faster).

Fortunately, I was able to record the sound with my video camera on and you can hear the sound at 0:16 as well as at 1:17.
Click here for the sound

The sound disappeared as soon as I turned off the engine, and reappeared as soon as I turned it back on (1:17).

As I was then driving the car back home, the noise went away and hasn't come back since.
The car has been sitting idle for a couple of days since and there is no sign of apparent leak under the car as far as I can tell.

I read several things on the forum but couldn't find a post with an attached audio of the problem, so I'm not sure what I have is the same as what I've read.

I'm kind of a newbie and would appreciate any advice or help that would help diagnose what this is/was.
Thanks in advance!

neanicu

That doesn't sound like engine noise to me.
It sounds like something that is belt driven. So either pulleys or belt itself...that's your noise.

rmc1148

Power steering pump ?

Macster

Sounds like my car did when what proved to be a valve in the power steering tank was bad.

With a hot engine and hot drivetrain (by hot just fully up to temperature), and when rolling to stop with the clutch pedal out and the tranny in neutral. The noise would go away when I depressed the clutch pedal only to come back the next time I did a roll to a stop with the clutch pedal out and the tranny in neutral.

The fix is to replace the tank with a new one. The tank comes with the valve. Porsche does not sell the valve separately. IIRC having this done at my dealer cost around $1000 (the tank is very expensive, labor not so much).

There might be a rebuild the valve fix or even a fix involving sourcing a suitable valve from some other vehicle's parts bin but I can't recall with any certainty.

Carlo_Carrera

Spray some WD40 on your engine belt when the car is idling and see if the whine goes away.

benoitroussel

Thanks for the replies!
Any reason why it would only happen when the car is hot?

"02996ttx50

power steering pump valve resonating.there's a tsb for it. common issue. engaging the clutch should make it stop. replace the ps pump reservoir if it bugs you. it's causing no harm, it's just annoying. i wouldn't spray any wd40 anywhere.

Carlo_Carrera

WD40 works great to stop a squeaky or whining belt so you can clearly hear if something else is making noise. Doing so is what is known as using the "process of elimination" to trouble shoot an issue. I also use WD40 to remove the rubber streaks off my paint from tire bits hitting my car at the track. I also use it to loosen rusty bolts. I also use it to lubricate the rear wing hydraulic rams after I wash my car. The car wash soap can dry out the external seals and cause the rams to leak. The WD40 repels any leftover soap and water and keeps the seals conditioned. I also use it to lubricate fuel injector O rings when I am replacing them. I used it just yesterday to lubricate the tabs on the new fuel door hing I installed. WD40 is a great product. I spray it everywhere.

Macster

While WD40 has its uses being used on a serpentine belt is not one of them.

As for lubricating the hydraulic rams of the Turbo spoiler, you go through the trouble of getting the dust covers out of the way to apply WD40 to the hydraulic cylinder piston rods after every wash?

Carlo_Carrera

A little WD40 on a belt is a great diagnostic tool. Hear a funny whine or chirp from the engine compartment? Spray a little WD40 on the belt an see if it goes away temporarily. If it doesn't move on to the next possible cause.

And yes I go through the trouble to adequately lube the rams after every wash. It is cheaper than having them fail and replacing them.

"02996ttx50

if it works for you? no problem. it's just not my cup of lube. i tried wd40 on the rams before i got them sorted out way back when. i just don't think spraying stuff on any part of these cars is advised, though it *may*? at times lessen the prevalence or occurrence of an issue. i just feel it's better to FIX stuff. but that's me. again, if it works for ya? cool. but i wouldn't advise spraying it anywhere, let alone a serp belt.. per macsters comment also.

add: in fact.. i'd put that right up there with spraying elec cleaner on a used dirty maf. i mean c'mon now.. really? lol ( not saying YOU would, just sayin ).. cheers


beno... this may give you some more info. do a search for the TSB 4897 ( i was unable to find it but have seen it before ) GL!. https://rennlist.com/forums/996-turb...-on-my-tt.html

Carlo_Carrera

I am not trying to beat a dead horse here but I am not "fixing" the belt or anything else with WD40.

You and everyone else are probably correct that it is the power steering making the noise but before we call it cased closed it might be worth while to check a couple of simple things as well. Spraying some WD40 or even soapy water on the belt to possibly silence it temporarily is a very simple and worthwhile diagnostic check.

"02996ttx50

i am only here to beat dead horses. why else would i be talking about a ps pump valve resonating as i have on probably ten other occasions lol..

but it's all good.. as they say..

OP. i listened to your VID. it's the power steering pump valve *resonating*. dollars to donuts. again, a *minor* annoyance in relative terms, and not cheap to fix per the above posts. i had mine done once under warranty. my 2nd tt seems to have dodged that particular defect. so far, anyway.

benoitroussel

Thanks a lot guys for the replies. I'll take care of this now that I know what it is.