car is making a hissing noise
Asked by dontcare69 Mar 20, 2012 at 12:31 PM about the 2005 Ford Mustang V6 Premium Coupe RWD
Question type: Maintenance & Repair
once my 2005 (V6) Ford Mustang is started and running, I am hearing a continued hissing noise which
gets worse once the car is driven. I thought it was a belt but not sure. The car's mileage is 42K. Thank
you so much for your advice.
3 Answers
aztec626bf answered 12 years ago
The problem could be a vacuum leak. If the hissing gets louder when you let off of the gas this would be my guess. Also could be EGR valve. EGR will usually give a check engine light, but not always. The code could come up "EGR" or "Small evap leak". One way to check for vacuum leaks is with starting fluid. If you have a suspect area of a vacuum leak spray just a little starting fluid there. If engine rpm increases you found the leak. With this one be careful not to overdo the starting fluid this stuff is very flammable. Just use very small shots.
