2002 Bombardier Quest 650XT Service Manual, Page 61Get this manual
Section 03 ENGINE Subsection 03 (LEAK TEST)
Diagnose
Listen for air leaks air escaping on intake portcarburetor means leaking intake valve(s) air escaping on exhaust port means leaking exhaust valve(s) air bubbles out of radiator means leaking cylinder head gasket airoil escaping from crankcase means damaged gasket andor loosened screws (refer to GEAR BOX) aircoolant escaping from cylinderhead means damaged gasket(s) andor loosened screws (refer to CYLINDER AND HEAD) air escaping into crankcase area means excessively worn cylinder andor broken piston ringsNOTE: For all the checkpoints mentioned above see the appropriate engine section to diagnose and repair the engine