MCI 102a3 heat question

Danny · January 17, 2018, 02:11:08 PM

I've had problem with the bus heat from the time I got the bus about 9 years ago. I've just about got it finished and would like to finally get the bus heat working - if possible.

The blower works for the defroster. The valve appears to work down left of the drivers seat on the floor. I've turned the valve open back in the engine compartment. No heat. Any ideas???

Templar52 · January 17, 2018, 02:32:53 PM

Check your circulating pump and modulating valve.

Taibob · January 17, 2018, 03:38:04 PM

There are usually two valves in the motor compartment.
one on supply line and opposite side return line

Danny · January 17, 2018, 03:46:59 PM

Thanks for the information - I'll check

buswarrior · January 17, 2018, 04:25:22 PM

One is easy, the return is down low on inside of the curb side engine access, right there on the floor.

The other is on top of the engine, just where the big pipe dives into the tunnel heading forward.

Look from outside, both sides, and down through the floor access inside, choose your best angle of attack.

happy coaching!
buswarrior

Danny · January 17, 2018, 07:20:42 PM

Thanks - I'll look for it when it warms up a bit this weekend

sledhead · January 18, 2018, 05:32:35 AM

on my 102c there is a heat control in the first bay from front on the passenger side up top behind a small fiberglass cover that opens the heat valve for the front heat . mine was a electronic control on the dash that went to this control

dave

Danny · January 18, 2018, 05:56:32 AM

Thanks

bevans6 · January 18, 2018, 08:16:43 AM

on my bus, which is admittedly a MC-5C, there are five valves that can influence driver's and coach heat. The main "out" valve is up behind the rear of the engine in the large line that feeds both coach heat and driver's heat. The main return line in the engine bay passenger side (engine cradle rail), also near the main temperature control electric valve for the coach heat and AC. This big return line/valve assembly combo only controls coach heat. There is a separate valve for driver's heat return at the top of the engine bay, driver's side, kind of above and inward of the rear electrical panel. This only controls driver's heat return. There is the driver's heat control valve beside the driver's seat. And finally there is the air-lock shrader valve on top of the driver's heat exchanger in the dash to bleed out air from that system.

Brian