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Discussion Starter · #1 ·
My S40 just started making a very high pitched hum as soon as I put the key in. It's coming from the middle of the engine bay, directly behind (cabin side) of the engine but forward of the fire wall (I can circle it on a picture if my description doesn't make sense). I've read about a diaphragm problem that has an extended warranty, but it doesn't really seem to fit the description, taking off the oil cap doesn't help and it's completely inaudible when the engine is running. After running the car for a bit it stops, so I'm guessing it won't make the noise by the time I get to the dealer tomorrow morning...

No CEL on and I was planning on taking it to the dealer tomorrow before this started so it's not really an emergency, but I was planning on taking a 4+ hour round trip tonight and just wanted to know if I should take it easy/it's just the oil filter diaphragm/it's nothing and I shouldn't worry at all

Muchas gracias
 

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While key is in the ignition and buzzing is present pop the hood and look at the silver cylinder in front of the battery with plastic lines off it. Can place ur hand on it and see if its vibrating.

That's the vacuum pump. There have been known issues between leaks and the relay system themselves tweaking out. Have had those cause numerous issues aside just from the noise since they are on the same fuse as the O2 sensors. There is a bulletin on them which requires an overload relay harness to be installed if found bad.

My guess would be there's either a leak or bad valve in which its just staying up.
 

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yep vacuum pump...
 

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Do you have a CD in your radio deck? I had a CD I forgot about on pause but never used it, as soon as I put the key in II I would hear strange noises. I finally one day decided to take out the CD and the noise was gone lol.

Other than that I agree with the rest of the guys on this one.
 

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Discussion Starter · #6 ·
Thank you all very much! I'll have them take care of that tomorrow.

You guys rock :thumbup:

Also the road trip was for the car's stock photoshoot, so get excited for pics of a car you've all seen a million times :p
 

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hmm mines been making a funny noise when i turn my car off. it makes like a very low toned whistle like air is excaping...
 
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