I recently took out my 99' Porsche Carrera from winter storage. It has 104,000 miles. It started right up. No weird noises.
When I got home after about a 5 mile drive that included expressway and city portions, I noticed a metal clicking noise that was very loud right next to the right rear wheel.
Listening to some UTube videos it kind sound like Piston slap. It increased slightly with RPM's or turning on the AC.
Now here is the thing, I turned off the engine and turned it back on and the sound was there. Then I stuck the car in the garage for a bit, went back out and started it and couldn't hear a thing wrong. Ran it for 15 minutes with AC blasting to stress everything and it is still quiet.
My question is, how can I tell if I had piston slap? It was a loud sound at that one time but it has not returned.? Is there anything I should do? Could the storage have impacted this?
I'm thinking of selling it and now this comes up.
Suggestions?
Edited to add Ytube link of sound
https://www.youtube.com/watch?v=Qle3bhfNizA&feature=youtu.be