WTF is this noise?

slupul · Post by **slupul** » 21 Feb 2016, 19:40

So it's a high pitched whirring/whining sound... reminiscent of a pig, perhaps a warthog. I've been told possibly SAS Pump bearings going bad? Or maybe SAS Valve (not sure the difference). It's not the serp belt or alternator, (have recently replaced both) the noise is coming from underneath the battery.

Advice? Thanks all!

-Lupul

Post by **erikv11** » 21 Feb 2016, 22:32

Almost certainly the SAS pump (i.e., the "air pump"). The pump is located under the battery, turns on at startup and suns for like 2 minutes then shuts off. Matches what you have in the video.

Best fix is to just get rid of the whole SAS system: http://volvospeed.com/vs_forum/topic/14 ... with-pics/

slupul · Post by **slupul** » 22 Feb 2016, 01:41

Thanks Eric. I hear that this violates Emissions standards... but like, I'm from Canada. I don't think we have emissions testing?? Aside from when it breaks, is there a compelling reason to delete the SAS from a performance standpoint?

Post by **rspi** » 22 Feb 2016, 05:42

It supposed to help the car run smoothly in extreme cold weather. Most bypass it electronically and leave the parts in place in case emissions inspectors look for them. Often an error code P0410 will come to tell you that the car is having issues with it. I have seen them come on randomly.

Post by **rspi** » 22 Feb 2016, 05:43

Kinda sounds like some little people have opened up a small factory in there. Lol

Post by **erikv11** » 22 Feb 2016, 07:22

Keep in mind, in 1998 a bunch of V70s shipped to Canada with the air pump, and a bunch shipped without it. The ones that shipped without it aren't violating any emissions standards, and realistically they are no more polluting than the ones that did. By driving a 1998 vehicle, you are doing far more for emissions on the planet than someone who throws away their car every few years for a new one that has more smog equipment. It takes a whole lot of resources to build 4 whole new cars over 20 years.

SAS will not affect performance, except that it gets in the way when you try to work on the car. It is especially satisfying to eliminate the valve that connects to the exhaust. Come armed with a 21 mm open end wrench and a lot of solvent. Fill the hole with an oil pan drain plug. Then marvel at how much more accessible the turbo becomes.

I don't think the SAS has any purpose to assist in extreme cold weather, rspi is probably thinking of is the corrugated metal pipe from the exhaust manifold to the airbox on NA models. Anyway, your turbo will always perform better when it is colder, about the last thing you want is to heat the intake air!

Post by **rspi** » 22 Feb 2016, 11:44

What is the purpose of the SAS?

Post by **abscate** » 22 Feb 2016, 11:52

It either pumps air into the exhaust manifold on overrun to help burn up stuff, or you use it to pick up a brand new Volvo on the tourist program..

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Post by **erikv11** » 22 Feb 2016, 13:16

rspi wrote:What is the purpose of the SAS?

The SAS pump pulls air from the airbox and feeds it to the exhaust, with the goal of getting more oxygen into the catalytic converter when the cat is cold. More oxygen helps the cat to heat up more quickly, so that it can be more effective.

The cat is cold on a cold start, so on cold starts the air pump runs for 3 minutes. It also turns on occasionally when you drive, I understood that is related to testing O2 sensor response and I don't know the details.

The point of the SAS valve is solely to protect the air pump: it keeps exhaust gases *out* of the air pump, the idea is the valve is only open when the pump is on, to ensure the flow is one-way from the air box into the exhaust.

slupul · Post by **slupul** » 23 Feb 2016, 00:02

^^That makes excellent sense, and definitely matches with the symptoms I'm experiencing. Did I read somewhere that without it, your engine will run a bit lean on cold start?