check valve or no check valve? '87 900T16

Just after thoughts to what people think of some advice i got from local saab garage (not dealer - private specalist uk). The check valve (oneway valve) that sits on the breather hose from the inlet manifold and the cam cover, apparently is of no use and does not matter if it is there or not. They removed it and didnt replace it. This was some time ago and i never noticed a difference, however i have known for a while the dump valve needed replacing and when i did replace it last week with a bosch standard dump valve I started having problems. The check engine light flickers when i come off boost quickly. Also replaced all old crummy vacuum hoses with nice new silicon ones *bling*. My idea was that the extra boost that the new dump valve was not leaking might be finding its way into the top of the engine and causing the warning light flicker. This probably exposes me as a rank amateur with no true idea about my engine but you've got to learn somehow!

so should i refit a check valve and could this solve this problem. if not any other more ideas?

Thanks Derek

PS the garage has just gone bust its a shame the mechanics were nice and helpful.

Reply to
derek huffadine
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It does matter, you do not want to pressurise the crankcase when the turbo comes on.

What "dump valve"? The waste gate?

Reply to
MH

He means the black plastic Bosch diverter recirc valve that can quack/squark/moo when the diaphram wears.

Reply to
NeedforSwede2

I think he means the bypass valve aka Hooter

Reply to
Malt_Hound

yes or just have no C valve or vacuum line at all just have a short line coming off the nipple from the valve cover with a bolt or something in the other end to block it off

then block of the intake manifold line too

Reply to
es

in article snipped-for-privacy@o13g2000cwo.googlegroups.com, es at snipped-for-privacy@yahoo.com wrote on 16/11/2005 01:48:

You must prevent charge air from pressurising the crank case. Remove the vac line, or put another on-way valve in immediately. Pressure will escape from somewhere, otherwise, and that is often through the bottom of the dipstick tube. Dramatic oil loss like that can lead to much worse problems very quickly.

If you can't get one from a car supplier, one from an aquarium supplier will do. If you don't believe me, connect a foot pump to it and pump a bar of pressure at it. That's more "boost" than you run on the car (I assume), so it's safe.

Like this?

I find I get closer to 30 MPG with the car setup like that. Odd?

... Of use it for something else ... Like a BOV in my case :)

Paul

1989 900 Turbo S
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Reply to
Paul Halliday

Thanks for that, seemed strange to remove something that was standard. Will replace the valve but block it off in the mean time. does anyone know where i can get a decent diagram or picture that shows the routing of vacuum hoses around a '87 900 T16S B202 engine cause looking at a few pictures ive got paranoid about mine. works fine so probably shouldnt worry - but you do, dont you?!

cheers for your help derek

Reply to
derek huffadine

in article hJLef.12865$ snipped-for-privacy@newsfe4-win.ntli.net, derek huffadine at derek snipped-for-privacy@ntlworld.com wrote on 16/11/2005 19:26:

LOL .. Sorry! :)

You've heard of hen's teeth, right? I'm not entirely sure there's a right or wrong way and years on, so long as all the vac lines suck and/or blow at the right time, anything is okay. Perhaps google for engine bay photos of C900s or have a browse through some of the online galleries?

is a good start.

That, or perhaps you could host a picture (or two) of your engine bay so we could draw arrows and circles all over it and make suggestions?

Paul

1989 900 Turbo S
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Reply to
Paul Halliday

If he wants to email me pics, I'll put 'em on a webserver for him.

Reply to
Dave Hinz

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