Saab Frequently Asked Questions
Find the air filter housing on the left side. Attached to it is the air mass meter followed by a tube and pipe. Follow that tube to the turbo and the bypass valve lives against the motor on the elbow of that tube where it attaches to the turbo. You need to remove all the tubes there to get to it and the one small hose running back from the bypass valve on the throttle plate to replace the valve. Be careful not to tear the rubber bits, they can get hard and brittle from heat. Tighten all the clamps while you are there. Be mindful of the two hoses that go into grommets on the tube the bypass valve attaches to. Pulling them off or pushing them on can push the grommets into the pipe. A shot of WD-40 on the grommets will let them slip back on the tubes. I usually use a tie wrap around the tube and the one forked small metal tube that fits inside the biggest grommet.
If the bypass valve is still held on with plastic clamps, replace them with regular metal cooling hose clamps, size 40 fits. If the vacuum line running to the valve is at all hard or swollen, replace it while it is off. Silicon vacuum line, if you can find it, is much better, especially on a turbo. It is resistant to heat and really holds itself on whatever you put it
Saab 900 79-94 Bypass Valve Photo
The bypass valve on a 9000 is much easier to get to that on a 900. It is located in the tube descending from the throttle plate to the intercooler. Diagnosis and function are the same as for the 900. On the 9000, the hoses on the valve's 90 degree ports may also be connected to the intake tubing with the same plastic clamps. We recommend changing these clamps to metal #40 hose clamps to prevent the hoses from coming loose should the plastic ones become brittle and break.