My school bus is overheating!!

[Shaylaxwright]

I have a 2004 frieghtliner cat allison 30ft school bus, it does well everywhere BUT this was our first time taking it on any HUGE hills. If anyone knows the road we went on the coquihalla in b.c notorious for its never ending incline. We didnt even get a quarter up it and our bus water temps where running over 150 close to 200 and started squealing. So, we put coolant in. That helped, slightly... we got a few km and decided to call it a night, checked the fluid and it needed another top up. Reason why we are worried slightly : it was record breaking low for temperatures in july at only 12 Celsius! So I couldnt imagine this thing even working at 25+ celcius- which is the normal temp. To top it off, we look out the window to see the front smoking. Come to find out, it wasnt smoking it was steaming? At the bottom right front under the bus there is a hose that blows out hot steam? What is it??????? We cant figure it out!! It also ticks under near the middle of the tires and is also connected to our batteries. It's been doing it for about an hour now and scared it will drain our batteries??!!

[Oldyeller]

A lot of things could cause an engine to overheat. The fact that you said you had to add coolant twice is concerning. Since this was posted on 7/2 I'm going to assume you've gotten the bus to a mechanic, if not do so ASAP and have the cooling system serviced before the engine is irreparably damaged. Good luck with this. Nothing worse than having mechanical problems on a trip, regardless of the vehicle.

[bus-bro]

Don't those things run close to 190? Topping it off with coolant might have overfilled the coolant, which caused the steam.

First thing I'd replace would be the radiator cap, and pull the dipstick. If you see milky oil on the stick you got problems.