Hi folks,

I wanted to mention something I experienced a while ago.

Since I've had my car, there's been a little hiss under the dash during engine operation. It doesn't change with revs, but does get louder if you turn the defrost on. After the car is turned off, you can still hear the hiss and it slowly fades after a minute or so.

I turned my car off in my driveway, and immediately popped the hood to check the oil. I had my head near the dipstick, looking at my new flame trap (nice and clean!), and I could hear that same hiss.

I am thinking brake booster, but my booster works. Hose is new, and made a great improvement over the collapsed old one. Shall I replace the check valve?

Thanks! Any musings or suggestions are welcome.

Ari