MC-9 radiators poor cooling

[cpschevy]

Anyone know how to make a mc-9 with 6v-92 and 740 auto cool better?

[JackConrad]

First step is to inspect your cooling system.  Are all seals around the radiators in place? Is the seal on the blower compartment door in good shape? Are the rubber pieces in the ends of the squirrel cage fans in good shape?  Is the blower drive belt tensioned properly?  Are you getting good water flow through all the tubes in the radiator core? Are thermostats working properly?  On our MC-8 we could answer YES to all of the above questions.  We then added an auxillary transmission cooler and lowered all temps (oil, water, & transmission) by about 10 degrees. YMMV, Jack

[Sammy]

Check the blades on the squirrel cages (blower wheels). Dirt accumulates on them, they no longer are concave and they will not pull enough air as they spin. Check the shutters if you have them, make sure they are  opening properly. Good luck.
Sammy 

[grantgoold]

I did as Jack suggests and replaced all the rubber seals around both radiators and the squirrel cages. Made sure to have the right tension on the belts and dropped my temp by 10 degrees. You can stand next to the radiator grill and a baseball cap will stay stuck against the grill. That has got to be good air movement. I am also considering the stainless air intakes/dams as one final augmentation to the cooling system.

I also live in Northern California where temps in the late summer are 100+ so every degree helps. I found a good rubber supply house, took an old seal to them and the got me what I needed. I then fabricated each seal (easy to do) and improved on the engineering of the originals.

Total cost was less than $50.00 including stainless steel screws to replace the old rusted bolts. 

One last effort, as this area was prone to rust and dirt, I por15 the whole area and it looks great!  Be careful not to get that stuff on you or the bus.

Good luck!

Grant
Sacramento

[TomC]

Since I have increased my radiator to the largest it can be and already have an 8 blade fan, I am going to try three things.  One, I've ordered a Hayden transcooler with a 12v fan built into it that I will install between the hot output from the transmission and the original shell cooler on the bus. It is rated at 31,000btu, so this should reduce the radiator strain.  Second, am going to have louvers made for my back engine door and install them high up to further get heat out of the engine compartment exiting to the natural vacuum of the rear of the bus.  Third, am going to install misters on the radiator as a last defense (have already bought the 12v all brass solenoid for it).  If it still heats up after all this, will just have to slow down, or stop to let it cool.  But from what I've read, should be alright.  Maybe you could incorporate any one of these additional help solutions.  Good Luck, TomC

[NJT 5573]

Getting rid of the big muffler really helps. It cuts the back pressure enough to take the load off the aftercooler. That takes a load off the radiator. A 3 feet X 2 feet muffler at 900 degrees laying beside the tranny and engine also radiates a lot of heat that you can't get out from under a coach. In Mexico the buses are all loud..... Its so hot, they don't live long with the restriction of a muffler. It also got me close to 1/2 MPG increase in fuel mileage, a noticeable power increase and a huge temperature drop in the engine bay. The 6V92 is not noticeably loud without the muffler in my Model 20. Hose the radiators out from the back to make sure they are clean and don't forget the air cleaner.

[Hartley]

I replaced my radiator cores with new ones. closed up the holes around the radiators that were allowing air
to get past the sides, bottom and top of the radiators.

Went from running 205 under highway load with a trailer to a cold 170 - 180 degrees, had to turn on the temp-stat louvers to get back to 195 for efficiency.

It's a pain to change the cores but fairly easy to get the radiators out and in again. The hard part is all the bolts and drilling
to move the old tanks to the new cores.

The new cores have 2 more rows of fins than the original. The old ones were clogged up probably 40% just from
old age and many miles.

General Radiator in Chicago is the least expensive @ $795.00 for the pair. includes all bolts and nuts amd gasket material.

I have an EX-New Jersey MC9 (1983 ), 6V92TA with HT740, I pull a 24 foot Pace trailer @ 4,000 lbs Plus.

Dave....

[belfert]

General Radiator in Chicago is the least expensive @ $795.00 for the pair. includes all bolts and nuts amd gasket material.

I wish I could get a new radiator at any price for my Dina, let alone $795 for two of them!  (Yes, I knew parts for a Dina might be hard to get when I bought a Dina!)

Actually, MCI has new radiators, but they charge $2200 for an assembley that includes charge air cooler.  I do not know of a third party selling Dina radiators and I called a number of them.

[NJT5047]

Getting rid of the big muffler really helps. It cuts the back pressure enough to take the load off the aftercooler. That takes a load off the radiator. A 3 feet X 2 feet muffler at 900 degrees laying beside the tranny and engine also radiates a lot of heat that you can't get out from under a coach. In Mexico the buses are all loud..... Its so hot, they don't live long with the restriction of a muffler. It also got me close to 1/2 MPG increase in fuel mileage, a noticeable power increase and a huge temperature drop in the engine bay. The 6V92 is not noticeably loud without the muffler in my Model 20. Hose the radiators out from the back to make sure they are clean and don't forget the air cleaner.

FWIW, ex-NJTs have catalytic converters in the mufflers.  Maybe.  Some have mysteriously fallen out.   That's another story.  The cats will stop up.  If your muffler has a joint with a clamp in the rear 1/3 of the muffler, you may wish to pull it and see if it's coked up.   
The cooling system on an MC9 is quite satifactory if it's in good condition.  The most common issues, as Jack states, is that more air leaks around the radiators than goes through them. 
You may want to check for rust-through in the blower compartment.  Any large rusted areas will cause overheating.
Everything else is common to all coaches....worn engine/transmissions make a lot of heat.  Radiators full of crap from poor coolant hygiene. The rads could be serviced.  Be ready to buy two radiators if they are removed.
Have not seen thermostats covered, and they can be problematic. 
Get one of those $50 buck infrared temp sensors and see what the various components are operating at.  Run the bus down the highway, and then into a rest stop...hop out and read everything...rads, muffler, LH and RH engine. Try to get a feel for the temps of the various components.  If you have one cool rad, and one hot rad....that's a problem...maybe.  If you see an gross unbalance, maybe that's a problem.  Maybe your guage is wrong?
Maybe the IR gun will show no problem.  That would be cool!
JR