Ticking Noise in 1995 K2500 GMC 6.5L Diesel

Volume 2 Issue 2 - 6.2/6.5 Issues and Answers

If you can help me solve this one, I’ll buy lunch! My ‘95 K2500 GMC has a ticking noise coming from the engine since the shop installed a new A/C pump. I can hear the ticking all the time that the engine is running except when I am coasting at speeds above about 35 MPH. If I let off the throttle at 70 MPH, the noise stops until I get down below about 35, at which point I begin to hear it again. It isn’t just me – everyone who rides in or drives it can hear the same noise. The shop says it is my tappets, that they are gummed up. Another shop guy thinks it is a broken piston. The noise was not there till the A/C repair. Any ideas for me? Remember, I buy lunch! Thanks for the great magazine! Rudy in Norway.

Hello Rudy. Will I have to come to Norway to collect lunch? When the shop was doing you’re A/C work, the mechanic...