Hello,

Two days ago, after driving my 2007 s40 t5 (about 80K miles) for about 1.5 hrs (highway), a high-pitched whiny/whistling sound started from under the hood. The noise occurs when the car is in motion and when parked. Note the attached zip file (and link below) contain a recording (.m4a file) from my phone of the noise.

https://soundcloud.com/user603582666/new-recording1

Any thoughts/ideas on what could be the cause? Thanks.

 

Hi and welcome to the forum.

You likely have a vacuum line loose or broken. I could NOT view/listen to your recording. You need to upload it to some website like YouTube.

 

Sounds like a bad PCV breather box. Remove the oil dipstick and see if it stops.

It might be free under a Volvo issued extended warranty.

 

Yup I agree with ES6T, it sounds like the pcv box.

 

The pcv whistle of death. Try forcing Volvo to replace the pcv and the leaking oil seals for free..


https://volvoforums.com/forum/volvo-...e-issue-55565/

 

Whistle of death? Most are already covered by an extended warranty by Volvo. No forcing needed. And it does not mean any oil seals are leaking.

 

If the PCV is clogged for too long, the seals will start leaking oil because of the crankcase pressure. Volvo doesn't cover the seals under the extended warranty, unfortunately.

 

Right. But the whistle is not from the PCV being clogged.

 

I dropped the car off at a local Volvo service center and they think "its a known issue" with, as many of you diagnosed, the PCV breather box. The center will only be able to work on the car next week, so I'll keep you guys posted on whether the problem was in fact due to breather box.

Thanks for the help!!!

 

So, what causes the problem, whistle?

 

Bad pressure control diaphragm in the oil filter housing

 

I just got the car back from the Volvo service center this afternoon and am pleased to announce the noise has gone away, although note I only drove the car for roughly 5-6 city miles. The following was replaced: "PCV Oil Trap and Ventilation Hose," "hose clamp", "cable tie," "cable tie," "sealing ring," "hose clamp," " oil filter hou[sick]", "Hose." Also, the parts fell under the extended warranty.

Thank you all for the advice!

 

the pvc valve releases pressure from your crankcase so that gaskets don't get blown. if it continues after that has been ruled out, check you alternator bearing..that happend to me once.

The PCV system pulls in contaminants in the vapor in the crankcase and feeds them into the intake to be burned. That's it's function and it's an emissions requirement. It should normally apply a slight vacuum to the crankcase and there should be a filtered supply for air to enter the crankcase thus creating a circuit of fresh air in, dirty/moist air out.
If the system gets plugged then pressure can build but pressure isn't the reason for the PCV, it's just a symptom of a problem.

 

The PTC valve isn't it? On the the turbo end of the air inlet supply pipe.

All relates to the PCV system.

ahhh. late thread on my part. Ignore please.

 

PTC and PCV are totally different. The PTC is often mistakenly called a valve on the boards. Also, on the new S40s, it isn't located in the inlet pipe because the PCV system is a different design.

 

You got me yet again ES6T but my hasty thread #14 went on with me omitting to read on to the 2nd page of responses.
I tweaked to the system difference also then, hence the edit to ignore.

 

Just had mine replaced at a cost of ZAR3k. No extended warranty cover as my T5 has done 180K km's However, took only about and hour or so and everything is quiet and back to normal

 

Same whistle sound on my newly purchased used S40. Except, high suction at the oil cap and dipstick instead of pressure. Took it to volvo and same diagnosis. Now waiting on parts under the extended warranty program.

 

I think I might have heard this whistle sound on my S40 last night, not sure, I'll have to check for it again today.

Can anyone tell me the terms of the extended warranty for this repair?

 

10 years or 120k miles
extended warranty #205