Screechy Sound on start up sometimes
 

Hi
Sometimes (prob every 5th start up) engine makes a kinda screechy sound, almost like a slipping belt, but if you rev the engine it doesnt screech again, so maybe its the starter motor ? It just screechs for like half a second on startup.
Any thoughts ?
thx
JOhn

Model year? Mileage?

Could be the starter, but I doubt it. More likely one of the ancillaries (alternator, AC compressor, PS pump, waterpump, or the belt tensioning roller or deflection rollers).

Try removing the rear engine cover and with the car cold try to start it up and isolate the sound. May need a helper with a stethoscope or even a cardboard tube to really find it.

If it's time to change the poly rib belt, once you have it off, hand turn all the pulleys and rollers and see if any are stiff or 'grindy' indicating their bearings are headed south.

Could be the starter solenoid sticking - this causes the flywheel to spin the starter motor breifly... it sounds pretty bad.

I've heard my car make the sound a few times. Generally not a huge issue, but if it happens a lot, it may need attention.

Thx guys, Ill try and isolate the noise, its a rather embarassing sound, not cool, the solenoid idea could be the one as it does not make any further noise after the initial start up, noise just lasts for a moment as engine fires up.

if it sounds like a belt slipping, then it's probably a belt slipping. since the belt on our cars is toothed, it will generally only slip if the idler pulley is freezing up and the back of the belt is dragging across it for a second.

you can pull the hatch behind the seats & remove the belt, then check to see if the idler pulley is hard to turn or if it feels wobbly. it may need to be replaced.

Ive isolated this noise and worked out its in starter motor, mechanic says clutch dust gets in around the pinion bearing in the starter motor, he says at next service we can pull the starter and replace the bearing if necessary.

Ugh! My '01 with 42K does the same thing when starting cold. I have a new serp belt that I was going to put on to see if that fixed the noise. Probably not! Just had the alternator and coolant overflow tank replaced (after leaving me stranded) and I just replaced the ignition switch yesterday, which is super easy BTW. It appears my car is molting one part at a time.

Ignition switch assembly was my issue
 

It was the ignition switch for me which caused the stater to clash for a short time. The switch travel started getting sloppy. It wanted to remain spring-loaded to the "first detent position", door bell remained on when key was removed, I had to push it to the off postion to remove.

On another note, beware of replacing the electrical portion of the ignition switch only. I read that some have had good luck with replacing just that part...not me.
I started out buying that part from autozone (previous threads) and it wound up being the mechanical portion of the assembly in front of it. I couldn't get it started, had to have it towed to Porsche (thought I activated the immobilizer) and Porsche stated the mechanical portion prevented the key from reaching the full travel to activate the starter. $277 later all is ok. Porsche asked how I was able to just buy the electrical part since they only can get the whole assembly. Their experience is that it is always the assembly that causes the issues.
btw, it took them 3.5 hours to remove.