21 top reasons why engines overheat - from another bus board - good info

[RTS/Daytona]

originally posted by luvrbus

Bus overheating 

I thought i would post this information here that Wayne Mullis of Desert West Coach gave me in 2000 called top 21 reasons your engine overheats     

1  Transmission oil level to high (Allision)     
2  Engine thermostats are sticking
3  Cooling system not holding pressure 8 psi when hot
4  Shutterstats stick; inhabits shutters from opening (if equipped)
5  Shutters sticking closed (if Equipped)
6  Engine tuneup:engine is not in good tune
7  Fan belt slipping
8  coolant mixture too strong
9  Water pump impeller slipping 
10 Blower bypass sticking open (if equipped)
11 Dirty air filter
12 Excessive exhaust pressure plugged or damaged muffler
13 Plugged or restricted radiators ,internally or externally
14 Dented or collapsed piping or hoses
15 Air trapped in cooling system
16 Coolant moving through cooling system to fast (seals on thermostats bad)
17 Mud flaps hanging from rear bumper
18 Faulty gauge or sensors
19 Inlet rings for squirrel cages bad (MCI)
20 Seals or gaskets bad on radiator door (MCI)
21 Driver caused overheating,lugging,not enough RPMs

[plyonsMC9]

Thanks Pete,

I missed this when originally posted.  Good stuff.

Can someone enlighten me tho' about the mud flaps off the rear bumper?  Perhaps in the way of the exhaust?

Kind Regards, Phil

[TomC]

Mud flap hanging from the rear bumper can trap the hot air under the bus.  Full length mud flap just behind the rear wheels, though, will create a low pressure under the bus that will suck the air away from the engine actually improving cooling.  Good Luck, TomC

[Marcus]

I still have overheating if I push it above 65, even after new radiators and thermostats. I did ckeck my tranny fluid level and it does appear to be about 4 inches up the stick beyound full. I will check it again when it's cold. How critical is that to the temp? Marcus

[JackConrad]

Did you check the transmission fluid with the engine running in neutral after putting the transmission in all gear positions with the gear selector and the fluid at operating temperature?  Jack

[Marcus]

Jack ,I drove the bus about 50 miles ,then parked it in neutral and checked the fluid. I did not put it in every gear after I parked it. I put about 10,000 miles on since tranny filter change. I think I will change it as well. Marcus

[Busnut83]

I have not checked this yet,,, but I had a mechanic that has his own mci-9,,, I told him them problems I have and he believes the hose at the top of the rad,,, small braided,,, if its blocked will cause overheating!!!

[Marcus]

My 9 is a 1982 ,and does't have the small braided hose. It appears to be a 2 inch pipe right out of the top , horizonally. Marcus

[HB of CJ]

22.   Fan belts MISSING because you heard a big bang and saw them bounce along the road behind the
      bus along with a lot of dirt and twigs and leaves and mud and stuff.

23.   Giant wasp or pack rat nests inside the duct work attached to the inside of the radiator thus
       busting loose underway then being sucked into the fan stopping it or slowing it down thus causing
       the aformentioned belts to bust.    

24.    The transverse admidships mud flap dohickie thing running across the width of the bus underneath
        in front of the engine but behind the side radiator falling off and not being there, thus not letting
        the side mounted radiator radiate.  

[plyonsMC9]

Mud flap hanging from the rear bumper can trap the hot air under the bus.  Full length mud flap just behind the rear wheels, though, will create a low pressure under the bus that will suck the air away from the engine actually improving cooling.  Good Luck, TomC

Fascinating Tom.  Your knowledge of these busses never ceases to amaze me.  I will keep this tip in mind.  Thank you.

Best Regards, Phil

[belfert]

My bus is not a 9, but the radiator has both a 2 1/2 hose and a small braided hose coming out of the top of the radiator.

[Hi yo silver]

Jack,
Thanks for answering a question that I had re. how to properly check the fluid.  Ran into that with the MC8 in NC.
HB of CJ, good ones!
Dennis