MCI 5 Cooling

[JPO]

My MCI 5 engine has 70 injectors at about 330 hp.  When towing and pulling a long 5-6% grade the water temp gets to 210+, in the summer when it hot out side I have to drop a gear lower than It would pull the grade and sometimes pull over and let it cool down.  The raditors look clean and I have sealed the blower compartment and around the raditors.  I have just pulled out the original heating system which consisted of squirl cage blowers and a good size raditor core.  I believe that it could be used for additional cooling for the engine.  Just by switching the blower cages and turning them they would exhust the hot air out the bottom of the bus.  The problem is how to get fresh cooler outside air in to the front of the heater core.  The fuel tank is in front of the heater core.  The 2 questions I have are:
1.  How does the air flow under the bus when traveling at highway speeds?
2.  Is the bottom of a MCI 5 bus part of the structure and can I cut a hole in it approx 1'x4'?

Thanks for the help
  JPO

[Ncbob]

You need to check and see if your shutterstats are opening (if your Bus has them) and make sure that the baffles on the bottom of the blowers are wide open at engine temperature. If all of the above are working properly you may have a thermostat that is not opening full when the engine temperature rises and it's calling for cooling.  There's a thermostat on each bank.

Too, are the fins on you radiators clean? Is your coolant topped off? I don't depand on the small valve to tgell me I have coolant in the tank...I get on a ladder and take the cap off and visually check that the tank is full.

Diesel engines fire on heat of compression and when you ask them to pull hard they have a tendancy to get hot unless you're staying within the suggested operating range of the engine. DON'T lug a Detroit! Your best operating range is between 1400 and 2000 RPM's. They like to rev...it's the nature of the beast.

My 5 pulls all the mountains I ask it to and belive it or not..I leave some of the 40'ers in my dust.

NCbob

[Ed Hackenbruch]

I would not cut that big of a hole in the bottom!  I wouldn't even cut one 1/4  that size.  I read somewhere that running at less than 1700 rpms you are not getting full efficiency out of your fans.  I keep a close eye on my tach and temp, and if i have to, i will drop a gear or two or three to keep the rpms up and the temp down.

[Chopper Scott]

Just because a radiator looks good on the outside doesn't mean it does on the inside. The bad part is they are not cheap to have done but then again neither is a burnt up motor.

[JPO]

My raditors are not the problem, its big injectors and my big foot.  I also have a late model 8V71 TA that I want to install.  It is rated at 400+ HP.
JPO