Screechy Sound on start up sometimes - 986 Forum - The Community for Porsche Boxster & Cayman Owners

benjoid · 08-19-2008, 05:42 PM

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

Lil bastard · 08-19-2008, 05:56 PM

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.

FrayAdjacent · 08-19-2008, 05:58 PM

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.

benjoid · 08-19-2008, 06:37 PM

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.

insite · 08-20-2008, 04:36 AM

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.

benjoid · 09-02-2008, 05:30 PM

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.