RV Repair: Onan Generator code 33, don hoffman, radiator cap

Question
We are desperate ! we have an Onan 7500 quiet diesel mounted on our 18 wheeler, it is shutting off with a 33 code, it runs for about 3hrs depending on the outside temperature. We have done everything we can to the cooling system, rodded the radiator, new thermastat, radiator cap, new computer, rewired the stator, new sensor, belt, serviced it, new water pump, rebuilt fuel injectors, checked the water temp, and it is still shutting down, HELP PLEASE !!!

Answer
Sounds like it might be an installation issue. Maybe the hot air discharge
is being drawn right back into our cooling air inlet , both are mounted on
the  bottom of this unit. If you want to take a couple of pictures of this
installation, get me the measurements from the ground to the bottom of the
gen set along with any other measurements that you can supply and send them
to me I will review and comment.
don.hoffman@elitervservices.com