View Full Version : 1GM10 rotates by hand

08-24-2008, 10:43 PM
"Hi All,
My 1GM10 sat for 6 months in the Arizona heat, I tried to decompress and turn it a couple of rotations to get some oil going and after that start it with the stop pulled out. After pushing the stop back in , it wouldn't start and rotates very light , I can rotate the pulleys and motor by hand. I took the valve cover off and the valves are not stuck and do move. What would be another cause for this type of compression loss?
What would be the next step in troubleshooting?

T Maxted
10-15-2008, 07:59 AM
Hi did you get any response for your query.
I am having the same problem.

10-16-2008, 06:12 PM
"No, but I talked to a diesel mechanic in San Diego who told me to softly tap on the valves with a hammer to see if that would free them up.
I first put miracle oil in the cylinder (I took the injector out), let it sit overnight, then rotate the motor to get the oil out, tap the valves put the injector back in bleed the system, and it fired right up!
Let me know if you need more info.