ISX EGR 550 hard to Start when Hot

[alamow]

I drive a 2010 Western Star with an ISX EGR 550hp which is hard to start when hot. The engine has covered 2.3 mil Km but had the head overhauled 18 months ago and new cams last month. Oil and water temps are stable.

Our State fatigue management rules allow 17 hours work time every 24 hours provided we take a 20 minute break from driving every 5 hours. If I shut down the engine during the 20 minute break I can not start the engine again. The symptom is a flat battery yet the batteries and all starter cables have been replaced, 3 Delco starter motors and now on the 4th which is a Mitsubishi. Additional earths have been added to the chassis and engine block, starter solenoids changed.

Once the engine has cooled (1.5hrs) the engine spins over at normal speed and starts. The Mitsubishi starter motor is an improvement requiring 30 mins cool off time. I run an icepack/APU when the engine is not running to keep the cab cool and batteries charged.

Cold or warm start absolutely no problems.

The truck tows triples (265k lbs) in high ambient temperature 38-47 cels. Fuel burn 2.7mpg.

Lately I just run the engine on high idle but it would be nice to shut the thing down and have a break from the noise and vibrations.

Any suggestions?