my car is a very angry monkey
 

I believe my car is possessed by a very angry monkey. My 2000 boxster base developed a constant Eeeekkkkkkkkkkk squeal while driving. The noise tends to disappear when RPMs are above 2500 and does not change noticeably with varying RPMS. The noise also stopped when I was carrying bananas home in the trunk from the grocery store. There is no smoke and no CELs but I believe it may be the AOS. The car must be at operating temperature before the noise starts and is soft but grows very loud over a minute or two. From what I have read, most AOS failures produce smoke and make the oil fill cap difficult to open due to an increase in vacuum. I do not experience these signs but when I loosen the oil fill cap the noise changes and will sometimes stop, while the car does run rough with the cap off of course. Does the AOS seem like the culprit? My other thought was a loose spark plug but the noise isn’t an Eek Eek Eek, but rather a screeching monkey. Are there any other maintenance items I should tackle at the same time? Thanks.

My guess...either a failing water pump or idler pulley bearing

I would agree that it could be the water pump because I have noticed small amounts of water under the car (approximately 5 inches diameter towards the rear). This appears while the car is running and does not accumulate while off. I attributed this to the AC? Although I do not remember noticing this before. My rebuttal is that the car must be at operating temperature and does not change with RPM except when it disappears. I thought the water pump would be more of a grinding sound that fluctuates with RPM.

My AC condensation appears at the right front wheel well area.

My car is an 01S. The AC drain hole is on the inside edge of the passenger foot well about where the center console transitions to the central tube.

I had to replace my water pump about three weeks ago. About 15 miles before it failed completely (pulley fell off the shaft), I heard a squeak, squeak, squeak sound at low rpms (below 2000). When the rpms went higher, the engine and road noise masked the squeak so it seemed to go away. Turning the AC on or off made no difference.

It easy to check the water pump - it just take time. Remove the front engine access cover and inspect the water pump for leaks or leak residue. If you see these symptoms, It time to replace the pump. My recommendation is to use Porsche parts only here. If you don't see a leak or residue, you can then remove the serpentine belt and check the water pump to see if the shaft wobbles or binds. If it does, it time to replace it. BTW: you might hear the noise as you turn the shaft.

It's important to check the water pump for two reasons. If the pump fails, it could leave you stranded or cause an overheat. More importantly, if the pump shaft wobbles because its bearings are failing, the impeller could break as it strikes the engine block and small pieces could block coolant passages in the engine. If the impeller is metal (non-OEM), it could score the block.

Good luck

I have an exactly same problem as well !!! It keeps producing squeeky sound whenever i start slowing down my car waiting for the traffic lights and its so annoying!!! I saw small drops of water coming out from the passenger platform and im worried its some form of bearing or pulley problem!!! anyone here could advice whats the problem? thanks

Did you try the bananas in the trunk trick? :D

Just sayin'....................

TO

I do believe it is the water pump. I looked under the passenger side, just in front of the rear wheel well and saw fluid all along this tube, but originating from towards the rear of the car.