BucketTrucker688 Posted May 27, 2019 Share Posted May 27, 2019 On my 91 the other day I experienced what I thought was a stuck on engine brake...pulled the valve covers and noticed 4 bent exhaust valve push rods. Also noticed the engine brake solenoids not activating at the same time, the rear solenoid activated way later than the front at a idle. Oil pressure seems to be fine 30+/- psi @ idle. I ran the truck all day and it was fine then at the end of the day in 8th gear (8ll trans) it started sounding like a bad miss or like it needed fuel filters. I didn't really notice it again until I needed to back up loaded up a hill then it got worse from there. I am the only driver of this truck and do not over rev what so ever. I also replaced the cam approximately 150k ago about 9 years ago when I got this truck. I plan on changing the push rods and engine brake solenoids and re adjust all the valves but I'm worried that's not the only thing I need to do. Quote Link to comment Share on other sites More sharing options...
Mack Technician Posted May 27, 2019 Share Posted May 27, 2019 Bent exhaust push tubes = injector slobber. Half burned fuel creates tar on the exhaust valves which glues the exhaust valves and bends tubes, esp exhaust tubes. Usually bends on cold start ups. Quote Link to comment Share on other sites More sharing options...
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