Can anyone help me troubleshoot this short rattle immediately after ignition?

It's sporadic and only happens on cold starts. The person who took video "Two" mentioned it may be from the rear (exhaust).

Any help would be appreciated.

George

One:

Two:

 

Can't help on that sound, and it is different than the one mine makes.

My GT3 makes a strange sound, and I will try to make a video of it that I can post. Only happens when going from cold start high idle to normal idle. It lasts about 3-4 seconds. Technician ideas include: (a) associated with changing cam timing and (b) seems to be coming from the secondary air pump on the engine. Anyone else experience similar?

 

Mine does that too. I think it's air purging out of the oil pump. It only happens when the car has been sitting overnight and air has gotten into the lines. You'll notice it occurs just as the oil pressure comes up. It's annoying but it doesn't seem to hurt anything.

 

Thank you; sounds plausible and I will watch the oil pressure gauge next time I start it. And I will add this to my list of suggestions for the tech to analyze next time I visit the dealership.

Interesting, because it is pretty loud and obnoxious on my car, but others say there GT3's never do it.

 

that I thought might be coming from the starter motor.

But, that is just a guess.

Let us know what you find out from your mechanic.

Thx.
Matthew

 

matrog,

Porsche service centre diagnosed it to be from the starter motor and had it replaced. Strangely it still makes this noise infrequently (perhaps once out of ten times).

 

I'm going to guess it's when the vacuum builds enough to activate the exhaust valves and it's the valves making the noise. Maybe try unplugging them and see if it still makes the noise.

 

for confirming it is an over-active starter motor.

 

thanks for your feedback

donuts:
I will look into it. I believe the problem may be related to the exhaust valves. Also had an issue of rough idling and a strange exhaust note (as if misfire) on colder days, clearly audible when in sport mode - until I floor the car on 1st gear so the car kind of "breathes" normally (and sometimes even then it wouldn't change). As if the exhaust valves were not opening properly or not opening fully. Porsche advised that a vacuum system failure would open the valves at all times and that it cannot be the problem.

matrog:
Will check the starter motor again as well. Will update this post once the issue is resolved.