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Discussion Starter · #1 ·
Hi all,

I got an upgraded check valve installed on my Viggen and after swapping out the valve cover gasket including the GS T7 head plug (T7 Head Plug, GenuineSaab.com) , I still see oil seeping out of the calve cover. Then I started to suspect the PCV check valve. It still works but I do need to blow with some force through it to open it up. Also I did see oil underneath where the check valve rests and only the engine side of the silicon hoses has oil, the other side is clean and when I connected it to the car with the engine running and unplug the output side of the valve, no air is coming out.

So I suspect that the check valve I installed is too hard for the engine to open!? I find that strange as it is the same check valve that EEuroparts recommends as an upgrade from the OEM plastic ones.

Check valve used:
Pierburg 7.20235.01.0

Has anyone else have experience with this plug and how easy should it be to open up the valve of the Pierburg check valve? IE what should normally be the cracking pressure of that line?
 

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"unplug the output side of the valve, no air is coming out."

The throttle body vacuum sucks air through the PCV valve (when not on boost), nothing should be blown through it towards the TB. I replaced mine (2004 9-5 Aero) with a valve looking just like that link. I'm sure they all come from the same factories in China! I never thought the exact vacuum requirement was an issue, bearing in mind the suction which can exist from the TB.

Reason - I also replaced the evap. line from the evap. valve to the TB, used a bit of fuel hose as opposed to the semi-rigid reinforced original pipe. It was sucked flat by the vacuum. Open SID shows that at constant unaccelerated moderate speed, the inlet pressure can be 300 - 500 mb or hectopascal which is less than half ambient air pressure. It'll suck a golf ball through a hose pipe, so I can't imagine the spring in that new valve resisting for long!

You mentioned silicone tube - that will weep oil or fuel eventually, even the PCV vapour.
 

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Discussion Starter · #3 ·
Hi Doug,

Yes, you are absolutely correct. After I wrote this and went out for shopping I realised this and did check the vacuum side.... Not a problem there, there is so much vacuum it can 'suck a golf ball through a hose', so to speak.

Still, I wonder why I still have oil coming out of that very specific spot of the engine that is, allegedly, due to high pressure in the engine block. I still have a Mod6 lying around to install.... perhaps I should do that before anything else.

As for the silicon tube, yes, it becomes quite slippery and such. You recommend using rubber? I find that the rubber hoses become very stiff and brittle quite quickly? The check valve is pretty stuck on the hose though...
 

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Get oil/gas resistant line. It should last for a number of years. The rubber is higher quality vs. the standard "vac line".

Definitely do the PCV #6 upgrade. See where that gets you.
 

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I'm sure they all come from the same factories in China! I never thought the exact vacuum requirement was an issue, bearing in mind the suction which can exist from the TB.
The Pierburg valves that the OP linked to are pretty nice. They're made in Italy, if I remember right (it's somewhere in Europe), and they look to be very well made. They can even be taken apart if you want to clean them. I have them on two of my three Saabs at the moment. I agree that they open a lot more easily if you suck on the TB side than if you blow on the engine side.
 
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