I mentioned about the engine noise in this thread -

https://rennlist.com/forums/997-gt2-...bout-this.html

In summary, My 25k miles 997.1 GT3RS 3.6L engine (no overrevs) was noted by the local agent to be making a whining noise that varies with engine rev. It is really only faintly audible but can be heard more clearly with the rear lid up and car stationary.

The mechs have tried removing all the belts and pulleys but the noise is still present so noise is not due to the belts and pulleys. They suggested an engine rebuild which I am contemplating as a possibility.

Other than that the car drives ok and power delivery seems to remain the same. There is no warning lights and all engine parameters are normal. Also just did a spirited run with the local porsche club - with speeds up to 150mph and engine revving at the 4-7k rpm range for a good portion of it - engine performed flawlessly.

Youtube vid of the engine is here not sure how to embed the video). You can hear the whistling noise as the engine is allowed to rev down. It is also present but obscured by the other noises when revving up and holding steady revs.

http://www.youtube.com/watch?v=nah1F...ature=youtu.be

Hope you guys can help.

thanks

her shann

 

Nobody knows. It could be anything on your serpentine belt or something internal to the engine. Do a UOA with Blackstone (they can ship you a container internationally) to get a reading of what's going on inside the block.

Meanwhile, with the help of a qualified mechanic, try disconnecting the serpentine and turning the engine over. Briefly repeat your rev test in the video. Obviously you're going without coolant circulation, so shut her off as soon as you're done revving/testing.

That's what I'd do first to isolate the source of your problem.

 

alternator?

 

Guys,he already removed the belt and ran it...read the whole post... Has your mechanic tried to listen with a stethoscope? That might help finding out more precisely where the noise is coming from : top,bottom,front,back... Oil analysis is a good advice. Get a sample and send it to Blackstone. Secondly,I'd have the technician run a leak down test. A compression test is good,but a leak down is better. If it passes the leak down there really isn't any point in a full rebuilt. The noise might be coming from timing chain,gears or something else,like timing chain tensioner or in the Variocam. As a matter of fact,at 25K with no overrevs and if you took care of maintenance,your mechanic must be joking to do a full rebuild...(have you overheated the engine at any point?)

 

not sure if that helps, but does it sound like this:


I recently had this on my base 996... I did not figure out what it is yet.

 

would it be fair to say it is a rotational sound?

 

Don't think it's engine failure related, but either way I would:

- Compression
- Leak down
- Remove oil and filter, cut filter in half to inspect
- Save a sample of oil and send for analyses

Check if car makes the same sound with clutch in and out.

I would go thru these steps before anything, like removing the engine. After that start checking cam gears, and chain, cam solenoids etc...

Just my 2 cents.

 

Sounds like an airleak or powersteering pump to me...due an oil change, see if anything odd in oil ?

 

Summary of suggestions so far:

1) Vacuum Pump near cylinder #1
2) variocam actuators
3) cam chain tensioners
4) do oil analysis
5) leak down test - to decide if rebuild necessary

Will revisit dealer with list of suggestions - prior to tearing down engine.

Will update again.

her shann

 

Been hearing of vacuum pumps going, I'd start there

 

I'd rule out #2 & #3 off that bat. Been there and saw enough cars with those symptoms trust me it's nothing like a whine. Let's hope your UOA gives you a pointer. Good luck.