PCV Breather Box

Mr. Detail · Post by **Mr. Detail** » 03 Jan 2022, 14:56

Hello, all & Happy 2K22 as my 17 yr. old has taught me.

Just wondering if someone can tell me if the link below for what they call an "oil separator" is the main part that would clog up after many miles of driving. I can't afford the $200+ for the whole kit so I was hoping replacing this alone would help my stalling problems after first starting up the car when it's cold. Is it hard to replace this oil separator? (Hrs.?)

I have already replaced the engine air filter, ignition coils, spark plugs, coolant sensor, thermostat and changed the oil with full synthetic. I however have never changed out this oil separator with the car having 172k miles on her. I have to hold my foot on the gas pedal when I first start the car in the morning to keep the rpm's around 1,000. If I don't touch the gas pedal the rpm's drop-down and the car begins to shake and sputter until the temp gauge reaches normal.

https://www.fcpeuro.com/Volvo-parts/V70 ... =6&d=58&v=

Thx!

Post by **chrism** » 03 Jan 2022, 16:33

Judging from the linked pic it appears that separator box has the built in diaphragm which would mean you have a non-turbo. In that case it’s very likely that the diaphragm is all coked up and not controlling the PCV vacuum any more. If that’s the case then a new box will be in order. If, on the other hand, you have a turbo engine with no diaphragm then you can probably flush the box out with carb cleaner and keep using it. On the turbos, however, there is a vacuum fitting “nipple”, as Volvo calls it” clogs up and is nearly impossible to clean out without breaking it. The dealer sells just the nipple with short hose sections attached.

Regardless of which engine you have you can count on replacing the hose that runs from the top of the box to a port up on top of the engine. Other than the items mentioned and a new manifold gasket you can generally clean out the rest of the system rather than replace with expensive parts.

So, in order to help others in offering advice, is it non-turbo?

Edit: note price from Tasca Volvo….

https://www.tascaparts.com/oem-parts/vo ... p-31338023

Edit number 2: I don’t know about the PCV causing the low idle. Have you cleaned out the throttle body lately?

Post by **abscate** » 03 Jan 2022, 17:35

I’m seeing NA in the sig

I would just clean out the box. Idle problems are probably vacuum leak in the hoses

Update - dumb$$ poster didnt apprecate the more complex P2 breather box vs P80

See update below from chrism

Mr. Detail · Post by **Mr. Detail** » 04 Jan 2022, 07:41

Yes sir, my P2 is indeed a "Non-Turbo".
and no I have not cleaned out the throttle body lately.
Is there a good video showing how to do that?

Mr. Detail · Post by **Mr. Detail** » 04 Jan 2022, 13:34

I found a good video but when cleaning the P2 throttle body do any of you guys completely remove it from the manifold?
The video states that you will do a better job when you do.

Post by **abscate** » 04 Jan 2022, 15:37

Remove it and keep the shaft from getting solvent into the electronics. I wet a cloth with solvent and sponge the residue off carefully.

Post by **chrism** » 04 Jan 2022, 19:51

abscate wrote: ↑03 Jan 2022, 17:35
I would just clean out the box. Idle problems are probably vacuum leak in the hoses

The problem with the NA cars' diaphragm controlled PCV vacuum is that the diaphragm chamber gets clogged up, well cooked, and eventually the diaphragm ruptures which subjects the crankcase to full manifold vacuum. In my case (pictured below) the high crankcase vacuum caused a high pitched squealing noise that was described by one person as air being sucked through the engine seals and playing them like a kazoo. Pulling the dipstick up a tiny bit allowed enough air to rush in and stop the squealing - temporary fix until I got around to replacing the breather box.

: Oil_Trap_03_NA.jpeg (59.15 KiB) Viewed 1697 times

Mr. Detail · Post by **Mr. Detail** » 05 Jan 2022, 06:53

Hey chrism, thank you for you post. I have a feeling that my "diaphragm chamber" looks just like yours did right now. I have not experienced the high pitched squealing noise as yet, so perhaps that is good. So do those plastic/rubber looking circular parts you show above come with the purchase of a new breather box? or do I need to order them separately?
I have owned my car since 2017 and have never cleaned out or bought a new breather box. The car has 171k miles on her and I now expect this to be my main culprit for the idle fluctuation when cold. I have faithfully changed the oil every 5k miles with full synthetic oil but unfortunately have not addressed the breather box. This could also explain why I have gotten a small amount of oil in a couple of the spark plug wells.

Post by **chrism** » 05 Jan 2022, 17:40

The diaphragm part comes integral to the box. You can see it in the parts house photos. I just opened up my old one out of curiosity and then took a picture of it.
Be careful when ordering a box as the large angled hose on the bottom comes in two different diameters where it connects to the engine block. I got the wrong size and had to transplant the hose from the old box to the new box.

Mr. Detail · Post by **Mr. Detail** » 06 Jan 2022, 08:19

So am I correct in my assumption that I must remove the manifold itself to access this breather box? If so, can anyone tell me how many hours it might take me to do this and can I even attempt this myself as an amateur mechanic.