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Another Squealer -What should I do?-

77K views 103 replies 29 participants last post by  tjsilva 
#1 ·
Well, my 2.4i has a higher pitch squealing noise similar to the ones in these threads.

http://forums.swedespeed.com/zerothread?id=80861
http://forums.swedespeed.com/zerothread?id=79944
http://forums.swedespeed.com/zerothread?id=80761

I have 60k miles and all maintenance is current. The noise started the other day and I've driven it some since.
Today, I got a check engine light and the code as read by the guy at Advance Auto is: P0171 - System too Lean. So naturally I thought it was a vacuum leak. And by the sounds of the other posts it's probably at the PCV valve. There is no oil leak, yet. http://********************/smile/emthup.gif The question is what should I do? I can take it to the dealer but they want $112 for a diagnostic check. She's out of warranty too so I'm basically paying for anything they have to do unless by some miracle I catch a break. So I would think to just dive in and replace the PCV valve. But then the scenario plays out where that's not the fix, maybe I replace all the oil filter housing stuff too, it's still not fixed and I end up taking it to the dealer where it's now certainly not covered by any kind of warranty because I've been in there monkeying around.


So take it to the dealer and hope for the best?
Start replacing stuff, it's probably just the PCV valve? I was poking around a little: isn't the PCV valve hidden under the plastic intake manifold?

Also, any recommendations for a dealer in the Baltimore area? I found four:
Annapolis Volvo
Koons, Owings Mills
Herb Gordon, Silver Spring
Bill Kidd, Cockeysville <- Where I bought it

Thanks!
Jake
 
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#53 ·
Re: (Oldman)

Hmmm...

That might actually work, if you can find a valve that operates roughly at the same pressure difference as the original diaphragm.

Also, I'm guessing again but most probably those cyclones are not that complicated and it should be fairly easy to check if they are clogged or not. The incoming air/oil mixture enters from top causing rotating flow inside. The oil eventually falls down and the air goes up with some residual fumes. Of course there's no point unless Oldman's suggestion works.
 
#54 ·
Re: (FinnSpeed)

Well we can see the center tube is what flows to the intake manifold, the outside are vents that lead back to the head. When there is pressure in the outer case the diaphragm is lifted away from the center and gases pass into the center tube and into the intake. A spring holds this in the open position. So it looks that if the diaphragm is broken then this sucker should be in the open position allowing MAX flow.

Same goes for a backfire would shoot thru the center tube and lift the diaphragm which would allow the flame to blow up the crank case. For some reason this valve seems to work in the opposite way of what I think it should work / do??
&#8230;
 
#55 ·
Re: Is that diaphragm supposed to be cracked? (GoBerserk)

Quote, originally posted by GoBerserk »
I also asked about all the grit and the service guys said that's how it's supposed to be - more of a trap than an oil/air separator. I was going to point out that I thought that was the purpose of the oil filter but decided against it.
The oil filter is keeping the oil clean from the oilpump to the bearings. If you had this much grit in there, it would have lunched everything. The grit you're seeing is basically from the top of the motor, it's carbon mainly, and it is intentionally being sucked into that chamber and trapped. The last place you want it is inside the engine where the filter can grab it.

Quote »
The orifices on the intake gasket are pretty large. And I think it would be unlikely that all four of them be totally clogged. And there is nothing but the top of the snorkel under the plastic intake manifold.
I'd blast out the carbon from the manifold passages with some good carburetor cleaner spray anyway. And be careful about that dust on the front of the motor, all those nooks and crannies can hold a lot. Might be best to not attempt to clean it, with the ports wide open, instead being careful putting the housing back.

When the techs said "they all do it", did they mean all the S40/V50's, or a wider range of Volvo motors? The oil system on the B5254T3 is pretty different from others, though the basic idea is similar.

Tom.
 
#56 ·
Re: (Oldman)

Quote, originally posted by Oldman »
For some reason this valve seems to work in the opposite way of what I think it should work / do?? &#8230;
I think the thing to realize is that the top of the diaphragm (under the cap) is at constant atmospheric pressure. So, if the crankcase pressure is higher than atm, the diaphragm lifts and opens the port allowing separated crankcase air to escape to the manifold.

A backfire would push pretty hard on the diaphragm from below, but it would be funneled down to a pretty small tube, stifling it, and as GoBerserk found, the cap is on there pretty well, so it's not going to fly out. Kind of blowing an internal raspberry if you see what I mean.


In this top view of the guts, the fitting on the left is crankcase gasses from the cam cover, the elbow on the right is going to the manifold, and the diaphragm is covering/sealing the hole in the very center. I bet there's a check valve in the housing where the elbow comes in at the right too.



Simple enough. Now - what tore the diaphragm?

Tom.
 
#57 ·
Re: (tmtalpey)

agree, but as noted above even if the diaphragm is broken it looks like the spring would hold the thing open and there would be max flow from crankcase to intake. So why is this leading to a clog system when you would assume this would lead to a FULL OPEN system. Maybe it is full open and ends up drawing way too much oil which then clogs the separators. Kinds of like constant full leads to full clogged upstream&#8230; As a side note since this thing breaks to full open, I would assume it would no longer function as a anti-backfire valve.. a crazy design.
 
#58 ·
Re: Another Squealer -What should I do?- (GoBerserk)

So the question is, what is making the squealing noise?

Is it just air passing through the cracked diaphragm? Or the cam bearings from inadequate lubrication due to the pressure in the crankcase? Is it possible that the buildup of crankcase pressure can reduce the oil pump's ability to lubricate the valve-train? You wouldn't trip a low oil pressure switch since there really would be oil pressure exiting the oil pump.
 
#59 ·
Re: (FinnSpeed)

I really doubt that those cyclones would clog. It doesn't seem like the holes are very small. But they would be easy to check.

As far as boost backwash is concerned: I have the naturally aspirated 2.4l. So no boost. But it would close under boost. The spring holds the diaphragm open. So with equal pressure on both sides the air goes right up to the intake. When the crankcase has more pressure it is also open. The only time it closes is when the intake has more pressure than the crankcase - as when it's under boost for a turbo.

So what would a torn gasket do in a naturally aspirated engine? Since the spring holds it open, either low pressure in the crank case or high pressure in the intake would normally close the diaphragm. But if it's torn it will never close. So clearly, in order to operate correctly the valve must close at some point.
 
#60 ·
Re: Is that diaphragm supposed to be cracked? (tmtalpey)

Quote, originally posted by tmtalpey »
When the techs said "they all do it", did they mean all the S40/V50's, or a wider range of Volvo motors? The oil system on the B5254T3 is pretty different from others, though the basic idea is similar.

He was referring to the S40/V50s only.
 
#61 ·
Re: (Oldman)

Quote, originally posted by Oldman »
agree, but as noted above even if the diaphragm is broken it looks like the spring would hold the thing open and there would be max flow from crankcase to intake. So why is this leading to a clog system when you would assume this would lead to a FULL OPEN system.

Oldman's right. With equal pressure on both sides the diaphragm is held up (by the spring) away from the center port.
 
#62 ·
Re: (Oldman)

Quote, originally posted by Oldman »
agree, but as noted above even if the diaphragm is broken it looks like the spring would hold the thing open and there would be max flow from crankcase to intake.
Only when the crankcase pressure exceeds the manifold pressure. With the valve open, the reverse flow can happen just as easily.

I guess I didn't realize GoBerserk's car was a 2.4i, now that I see the manifold gasket has no reed valves that makes sense - no boost to hold back.

RedV50 - I think the squealing could be any number of sources. In your case I thought you blew out cam seals, which means the pressure wasn't venting at all. So, yours was clogged and/or the valve was stuck shut. Somewhat different I think, IOW.

Tom.
 
#63 ·
Re: (GoBerserk)

Quote, originally posted by GoBerserk »
IThe only time it closes is when the intake has more pressure than the crankcase - as when it's under boost for a turbo.
I don't think so, the only thing that moves the diaphragm is the relative difference between crankcase and atmospheric.

Tom.
 
#64 ·
Re: Another Squealer -What should I do?- (RedV50)

Quote, originally posted by RedV50 »
So the question is, what is making the squealing noise?

Is it just air passing through the cracked diaphragm? Or the cam bearings from inadequate lubrication due to the pressure in the crankcase? Is it possible that the buildup of crankcase pressure can reduce the oil pump's ability to lubricate the valve-train? You wouldn't trip a low oil pressure switch since there really would be oil pressure exiting the oil pump.

Your cam seals blew out right? Was the loss of oil there the cause for your cam bearing failure? Really the question I want to ask is: has anyone whose cam seals haven't failed had a oil delivery problem?

Which essentially goes back to the original question of what is the squealing noise? It seems like it could be an air noise. Either through the diaphragm or through the small vents in the top of the diaphragm housing. But then again it sounds like a bad bearing too.
 
#65 ·
Re: (tmtalpey)

Quote, originally posted by tmtalpey »

I don't think so, the only thing that moves the diaphragm is the relative difference between crankcase and atmospheric.

Tom.

I would not say "only" but "most of the time". If the valve is closed (crank case at lower pressure than atmosphere) then it seals the center tube which is connected to the intake. Now the intake pressure has an area of action on the diaphragm. So if the intake pressure goes up high enough it's conceivable that it would push the diaphragm off the center port. The crank case has a lot more acting area than the intake. So the pressure would have to be pretty high in comparison.
 
#66 ·
Well, if there is a check valve then the the intake can't force the diaphragm open. But then the crankcase gas will have a hard time pushing open that check valve if there is higher pressure there. But on a naturally aspirated engine there is usually less than 1 atm in the intake manifold. Only in the event of a back fire would there be greater than 1 atm. So it's sucking on the oil separator most of the time. Which raises another scenario. If the diaphragm is closed and there is low pressure at the intake manifold (FWIW my Miata pulls 20-25 in Hg less than atmospheric at idle) And the crankcase was at 1 atm the valve would be held closed by the intake vacuum.
 
#67 ·
Re: (tmtalpey)

Quote, originally posted by tmtalpey »

RedV50 - I think the squealing could be any number of sources. In your case I thought you blew out cam seals, which means the pressure wasn't venting at all. So, yours was clogged and/or the valve was stuck shut. Somewhat different I think, IOW.

Yes my cam seals did blow out. I assume the crankcase pressure just deformed and destroyed them. But the squealing sound did sound like it was coming from the cam bearings or at least under the valve cover. Yea I can see how that cracked diaphragm can make a lot of noise, but I don't think it was the noise I was hearing.
 
#70 ·
Re: Another Squealer -What should I do?- (Wish2k)

Just FYI:

I visited my dealer to take care of a minor warranty issue and happened to spot a work order for a Volvo S80, unfortunately it did not list which engine. It said: Recall PCV...
 
#71 ·
GoBerserk - Great research and this should help us DIYers... how much was the part? I wonder if the diaphram issue is the only major problem with this design or if the whole part is flawed. If so, I wonder if there is something we can do to mod it...

Oldman - Question regarding the catch can, if its installed after the "PCV", we'd still have a problem with the diaphram right? I do think its probably a good failsafe though for prevention on the PCV failure.

Wish - Did you get your car back, what was the diagnosis?
 
#72 ·
Re: Another Squealer -What should I do?- (mattdogg02)

It was about $140 from the dealer. That included the seals. Another dealer had quoted me $115ish and then another $16 or so for the seals. But Dealer #1 said the seals are included in the one part number, so I don't know what parts Dealer #2 was quoting me for. I know I ordered the right part from Dealer #1 because I had the darn thing with me. I also got a new oil filter $9 and a new intake manifold gasket $40ish. But normally you don't have to take off the intake manifold.
 
#76 ·
Done!

Yesterday my parts came in and I put her back together. It went surprisingly well.
Turns out a new Oil Trap (this is what Volvo calls what we've been calling the Oil Filter Housing) comes with a brand new oil filter already installed.

New in the box.


That's pretty!


Hosed


After I got it back together it took a few moments of cranking for the fuel pressure to build and then she fired right up. The "Running Lean" code I had before is gone now and hasn't come back in 100 miles of driving.

Here's a "gotcha" though: There are two holes on the front of the oil trap. One's for mounting the oil dipstick and the other is for holding a wire loom clamp. They're not threaded! The screws are self-tapping! That seems a little odd to me. And it's a little bit of a pain getting them started when the unit is in the car already. So it may be wise to tap those holes with the unit out of the car. Also, if you've taken them out and didn't label them the long one is for the dipstick and the short one is for the cable clamp.

Also, for tightening torques "Snug" actually means:
Intake Manifold, upper, plastic: 10Nm (7ft-lbs)
Intake Manifold, lower, aluminum: 19Nm (14ft-lbs)
Oil Trap: 16Nm (12ft-lbs)
Oil Plug: 38Nm (28ft-lbs)

If I were to do this again I wouldn't take the intake manifold off. If you can get the airbox out without dropping the radiator then good - do that. But if not I think there is enough room to do the work with the airbox pushed as far to the driver's side as possible. Working room would be restricted. But it's only 6 bolts, two hoses and one electrical connector.
 
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