Very strange whine when revving

wanderzz · 10-28-2011, 12:04 PM

Just got back from a short drive after changing the spark plugs. I was revving the engine to about 6k and as the revs drop I heard the strangest noise. It was a loud out of sync rev drop of something else that was spinning. It sounded very similar to those toy cars that had the ripcord that when pulled would cause the wheels to spin.

The car is a 2008 Cayman S with 42k on it.

Any thoughts?

Dale_K · 10-28-2011, 01:20 PM

Some year Boxsters have a one-way clutch on the alternator but I don't know about the newer cars like yours. That's only a guess. I really don't know.

JFP in PA · 10-28-2011, 02:01 PM

Are you sure you properly torqued the new plugs? Loose plugs often make a faint squealing sound.....

wanderzz · 10-28-2011, 02:38 PM

I believe so. This really sounds like something spinning - at least to my novice ears.

jporschef · 10-29-2011, 01:59 PM

I have started hearing something that could be described this way in my 2002 Boxster. I have not touched my plugs recently, but they would have to be physically loose to cause any noise. I would not assume they are the cause just because you recently worked on them.

My sound is a lower pitched rev down following the engine rev down, as if something was spun up with the engine and then slows down after the engine is no longer at high rpm. If I rev the engine in neutral, I do not hear this, but I do if coming to a stop quickly, still spinning down after the car has stopped so not the brakes. This is not very noticeable, you have to listen closely to hear it. Perhaps it could be the water pump or alternator or something related to the clutch, dual mass flywheel.

Chris Foreman
2002 Boxster

wanderzz · 10-30-2011, 12:02 PM

I took the front motor cover off and went for a drive. I can smell coolant but the sound sounds like the passenger side.

randy_k · randy_k's Garage

Have you noticed any strange fluctuation in the temps of the engine that you didn't see before. Also, It may be a good idea to check the dip stick/oil level and water levels of the coolant tank...
Randy

wanderzz · 10-30-2011, 01:44 PM

Unfortunately the Cayman seems to have an idiot gauge for temp and the according to the digital oil level check all is well. I added two quarts a few weeks ago when the low coolant light came on.

randy_k · randy_k's Garage

I'll just put it out there. First, Screw the digital oil level check. Pull the dip stick. You just wanna make sure the water is not going into the engine and raising the oil level. I'm by no means an expert on your Cayman. But not a bad Idea to check that.
As far as the weird whining when you decelerate/revs come down. I'll ask others here. Could the blades on the water pump come lose from the bearing and are free wheeling. The pump, if like a Boxster, is on the passenger side of the front of the engine? Just a thought.
Randy

wanderzz · 10-30-2011, 02:32 PM

Is there a place for a dip stick?

randy_k · randy_k's Garage

Quote:

Originally Posted by wanderzz

Is there a place for a dip stick?

Just shows how much I know about your car. Just did a seach for it and apparently not. I find that hard to believe. Put the faith in a digital gauge.
Sorry for the bad advice on that one.
Randy

wanderzz · 10-30-2011, 03:13 PM

I wish there was a dipstick. I really don't like relying on the digital unit.

randy_k · randy_k's Garage

I bet. My Boxster has digital one as well. I couldn't even tell you the last time I looked at it!!!
Maybe the first week or so I owned the car. Just seems stupid to me. To many things to go wrong that could effect what it's reading.
Randy

wanderzz · 06:53 AM

It is at the dealer right now and I was told below low two quarts is not a problem for this to happen. I was told they pressurized the coolant system and no leaks were found.

Does this sound normal?

As for the whining sound that spins out of sync with the motor. They don't hear it - obviously..

BTW, they hooked it up to the PIWIS and said the oil was overfull. I filled it to the line on the digital display. Well it was in the red he said. Sure would be nice just to have a dipstick..

1968SWTs · 1968SWTs's Garage

Quote:

Originally Posted by wanderzz

Just got back from a short drive after changing the spark plugs. I was revving the engine to about 6k and as the revs drop I heard the strangest noise. It was a loud out of sync rev drop of something else that was spinning. It sounded very similar to those toy cars that had the ripcord that when pulled would cause the wheels to spin.

The car is a 2008 Cayman S with 42k on it.

Any thoughts?

someone else had the same thing - but this one is not water cooled

Nostril Cheese · 03-16-2014, 01:05 AM

Quote:

Originally Posted by wanderzz

It is at the dealer right now and I was told below low two quarts is not a problem for this to happen. I was told they pressurized the coolant system and no leaks were found.

Does this sound normal?

As for the whining sound that spins out of sync with the motor. They don't hear it - obviously..

BTW, they hooked it up to the PIWIS and said the oil was overfull. I filled it to the line on the digital display. Well it was in the red he said. Sure would be nice just to have a dipstick..

Low pitch or high pitch whining? Maybe a belt idler pulley?

The oil level is always kind of a pain on these... What I do is fill it up with 7.5-8 quarts, start the car, let it warm up to operating temp and re-check level. It will go up. If you fill it to 9 quarts cold, you will overfill the engine.