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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: vintoolong on February 14, 2022, 07:17:18 PM

Title: MCI MC-12 Detroit Diesel 50 auxiliary water pump plumbing
Post by: vintoolong on February 14, 2022, 07:17:18 PM
Question for all of the amazingly helpful and knowledgeable busmeisters.
My MC-12 apparently had some sort of auxiliary heater.
It's gone. But the auxiliary water pump remains...sort of.
The pump bracket fell off the floor and ripped the hose that attaches it to the central water pipe. I closed the return valve and blocked off the engine heater outlet in order to get it home.
No hose of the right size was available. The pump was just laying on top of stuff in the engine bay. Does the bus need this extra pump or can I route the heat from the engine directly to central water pipe. Any suggestions?

Title: Re: MCI MC-12 Detroit Diesel 50 auxiliary water pump plumbing
Post by: buswarrior on February 15, 2022, 04:13:35 PM
If it was plumbed like the things that followed, the coolant passed through the coolant boiler on its way to the coach heat and defroster.

There may be a feedback loop as part of this install, with a similar valve in it to the stock coach heat one.

You may connect the output from the engine, to the pipes heading forward, bypassing where the coolant boiler was. If the feedback loop is present, it is imperative that it either is closed, or properly operational, as uncontrolled open will contribute to an engine overheat. Controlled opening is what keeps the engine at operating temperature, when it is too cold out for the 4 stroke to make good heat.

Clear as mud...

Happy coaching!
Buswarrior
Title: Re: MCI MC-12 Detroit Diesel 50 auxiliary water pump plumbing
Post by: ustenor on June 24, 2023, 05:02:33 AM
I have the same setup. 99 mc12, cat c10 engine. My pump is leaking. Where is the shutoff to the pump? Is there one?