1999 mazda protege lx 1.6, 99,000 miles, auto transmission. my girlfriends protege has recently begun making a knocking sound when the vents are turned on - in any setting (heat, a/c, etc..) it only makes the noise when the air is on, as soon as its turned off the noise goes away. the engine was recently replaced because the guy who she left it with during our deployment ran it dry with no oil and blew a piston through the engine. about a month after she got it back i changed the spark plugs only to find the guy who did all the work hadnt tightened the plugs into place - i could remove by hand. also he left a sensor plug disconnected and didnt tighten the battery tiedown. when she picked up the car from him he also told her that the tranny mount needed to be replaced. we have done plenty of maintenance on her car - took apart throttle body and intake manifold and cleaned them thouroughly, cleaned egr valve, replaced air filter and plugs. she is in need of an oil change...i fear he used generic brand oil and i know he used a generic brand oil filter. but again the noise only comes from the vents being turned on so i dont believe the oil would be causeing this. any ideas would be greatly appreciated. thank you.
Nov 10, 2007 at 5:31 PM