Question about Giant Heat Exchanger removal

[Sebulba]

If your MCI is anything like our GM, you'll need to check the rubber hoses which connect the defroster core to the hard copper lines for condition. They are easy to miss since they're hidden in the dash, and they are a potential leak point.

Thanks for the heads up on that. 

Seb

[Sebulba]

I removed the items you mentioned last summer. Here is how I bypassed the heat exchanger.

You can see the two copper caps I sweated on. This was discussed in my build trlhread I think.
This allows fluid to run to the front.

Also, one of the shut off valves in the engine compartment is more easily accessed from the trap door in the rear of the bus.

Another pic of it empty and painted.

Great info and pictures! 

So it seems that taking out the heat exchanger. I can just cap it off.  This is what I wasn't sure about.  I wondered if it needed to flow through the heat exchanger to continue up front to the defrost.  It seems that it does not.

Thanks for that great info.

Seb

[buswarrior]

It is common for the last commercial operator to close the heating valves in an attempt to get the AC to work better, rather than repair the controls, as the bus completes it's last tour of duty before being discarded.

So good chance nothing is wrong.

Yes, the defroster receives unmolested hot coolant direct from the engine, and returns, not via the big heat exchanger.

Happy coaching!
Buswarrior

[Tedsoldbus]

I turned on dash heat and fan last November to try to warm up the bus for my 90 year old father in law's quarterly ride. It didn't work so I shut it off, turned on the generator, and gave him roof air heat.
  A few months ago I had a "knows his stuff guy" look and he showed where my valves were, and they were in fact open. He said this is not a pick up truck. You have to get it good and warm for a while before it pushes hot fluid aaaasall the way to the dash.
So next trip I ran the bus for 25 minutes on a "just run the bus" outing. Turned on the heat on the way back. Mucho warmo. My dash heat did not work because I am impatient.....and like you Seb, a new guy.
My hat is off to you on your courage. When I mess with things like you are doing, a big spring flies past my head and resides somewhere in my front yard. Stay at it buddy. You have the best teachers at your fingertips.

[epretot]

Here is another picture showing the smaller line that allows the fluid to continue through.

[luvrbus]

You may not find valves to open on the series 60 mine were at the Webasto drivers' side under the floor access through side engine door

[richard5933]

I turned on dash heat and fan last November to try to warm up the bus for my 90 year old father in law's quarterly ride. It didn't work so I shut it off, turned on the generator, and gave him roof air heat.
  A few months ago I had a "knows his stuff guy" look and he showed where my valves were, and they were in fact open. He said this is not a pick up truck. You have to get it good and warm for a while before it pushes hot fluid aaaasall the way to the dash.
So next trip I ran the bus for 25 minutes on a "just run the bus" outing. Turned on the heat on the way back. Mucho warmo. My dash heat did not work because I am impatient.....and like you Seb, a new guy.
My hat is off to you on your courage. When I mess with things like you are doing, a big spring flies past my head and resides somewhere in my front yard. Stay at it buddy. You have the best teachers at your fingertips.

Do you have a re-circ pump in your system to bring the engine-heated fluid to the front? GM buses use a small pump to bring the warm coolant forward, and I'm assuming that other buses use something similar. What I've seen is many pulling the pumps when they pull the OTR heat, leaving only natural circulation to move the heat forward.

There are small coolant pumps which can be added to replace the OEM pumps, and perhaps this would help bring heat forward much faster.

[Sebulba]

It is common for the last commercial operator to close the heating valves in an attempt to get the AC to work better, rather than repair the controls, as the bus completes it's last tour of duty before being discarded.

So good chance nothing is wrong.

Yes, the defroster receives unmolested hot coolant direct from the engine, and returns, not via the big heat exchanger.

Happy coaching!
Buswarrior

Great, thanks

Seb

[Sebulba]

I turned on dash heat and fan last November to try to warm up the bus for my 90 year old father in law's quarterly ride. It didn't work so I shut it off, turned on the generator, and gave him roof air heat.
  A few months ago I had a "knows his stuff guy" look and he showed where my valves were, and they were in fact open. He said this is not a pick up truck. You have to get it good and warm for a while before it pushes hot fluid aaaasall the way to the dash.
So next trip I ran the bus for 25 minutes on a "just run the bus" outing. Turned on the heat on the way back. Mucho warmo. My dash heat did not work because I am impatient.....and like you Seb, a new guy.
My hat is off to you on your courage. When I mess with things like you are doing, a big spring flies past my head and resides somewhere in my front yard. Stay at it buddy. You have the best teachers at your fingertips.

That makes sense.  I have noticed that this beast does take a long time to get to operating temp.  Of course we have only owned it in cold temps so far.

Thanks for the encouragement, and I agree, the knowledge on this forum is priceless.

Thanks all,
Seb

[Sebulba]

Do you have a re-circ pump in your system to bring the engine-heated fluid to the front? GM buses use a small pump to bring the warm coolant forward, and I'm assuming that other buses use something similar. What I've seen is many pulling the pumps when they pull the OTR heat, leaving only natural circulation to move the heat forward.

There are small coolant pumps which can be added to replace the OEM pumps, and perhaps this would help bring heat forward much faster.

I don't know if there is a pump.  I will be on the lookout for that.

Thanks

Seb

[Sebulba]

You may not find valves to open on the series 60 mine were at the Webasto drivers' side under the floor access through side engine door

I think I know where one is.  I can access it from the driver's side engine door.  Not sure about the other.  Will have to explore.

Thanks for the clues.

Seb

[Sebulba]

Here is another picture showing the smaller line that allows the fluid to continue through.

Ok, thanks for the picture.  That could help.

Seb

[buswarrior]

I don't know if there is a pump.  I will be on the lookout for that.

Thanks

Seb

The only circulation pump is associated with the aux heater/coolant boiler, MCI let the engine water pump shove the coolant forward to the heat exchangers.

Never did figure out why GM felt the need to have that electric pump?

Happy coaching!
Buswarrior