Oh boy.

Jeep 4.7L sounds horrible and loud when running.

Just finished a head gasket job. But when I started up my Jeep it sounds VERY loud and just like a frickin lawnmower!!

Engine also rattles and shakes when running. I dont know what to do!! Im also afraid to leave it running for more than a few seconds.

Please help!!

first, check to make sure the valves are adjusted right on the rocker arms being the right torque specs. Then look for exhaust leaks.

follow scotty if no improvement maybe try motor mounts...exhaust..scan for codes...