I took Ford Iveco horse lorry out on the weekend to a competition and when i arrived at the comp, switched the engine off, the air system was hissing sounded like a small set of bag pipes coming from the air compressor system. This hissing continued for the entire time i was there approximately 5-6 hours, and again when i returned home, what could be causing this? there was no lights on the dash to suggest a problem however the pressure was close to 9 Bar on the gauge, 12 is the maximum on the gauge is it perhaps struggling to release the air? PRV fault?

i'm not sure...

sara, April 2009

air leak need reapired if stoped by vosa can be a big problem,usually easy to fix

john daf, April 2009

Are you sure the sound was coming from the air system? If you could be so sure, can you not identify which part of the system it's coming from?

JD, April 2009

may have a one way valve fitted somewhere on compressor outlet pipe, it may not be seating and allowing air to exhaust through compressor inlet pipe!

k, April 2009