BCM Community
Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Sebulba on March 18, 2022, 03:01:46 PM
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Hello All,
We are making steady progress on our conversion. I have the wheel chair lift is now removed, so we have gained another useful bay. Also the Air conditioner compressor is removed (198 lbs).
Now I am wondering about the removal of the over the road HVAC parts in the area adjacent to the fuel tank. I have opened the door in the rear bay and looked in there and then closed it slowly so as to forget I ever saw it. :o
Now I am getting braver and wanting to get this stuff gone, thus lightening my load and gaining some useful space.
My question: is there a valve (or 2) that isolate the giant heat exchanger so that I can remove it without much coolant loss. If so, would the valves be close to the heat exchanger or?
Also any other tricks/advise you may have for this removal project are welcome.
Thanks, as always, for your generous help
Seb
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start by shutting off the large gate valves in engine compartment.
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start by shutting off the large gate valves in engine compartment.
Super, I have a feeling they may already be off since I have never had heat in this baby.
Seb
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What are you going to do for a windshield defroster? Or, are you leaving that heater core up in the dash?
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What are you going to do for a windshield defroster? Or, are you leaving that heater core up in the dash?
Bad move if he removes the dash heat
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What are you going to do for a windshield defroster? Or, are you leaving that heater core up in the dash?
So far that one is still there, although, I haven't figured out how to get heat (hot water) to flow through it yet.
Seb
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Bad move if he removes the dash heat
I agree, that is a good thing to keep.
Seb
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If the big valves in the engine room are closed, there is no hot coolant flowing anywhere forward, so no dash heat either.
You must cap the lines leading to the big heat exchanger, and maintain the lines that branch off to continue the journey to and from the dash. Work backwards from the very edge of the heat exchanger connections to figure out a good place to cap them.
Both of those exchangers, heat and AC, will get you some proper scrap money.
Happy coaching!
Buswarrior
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We love our toasty oem otr heat at dash (defroster) & cabin...
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If the big valves in the engine room are closed, there is no hot coolant flowing anywhere forward, so no dash heat either.
You must cap the lines leading to the big heat exchanger, and maintain the lines that branch off to continue the journey to and from the dash. Work backwards from the very edge of the heat exchanger connections to figure out a good place to cap them.
Both of those exchangers, heat and AC, will get you some proper scrap money.
Happy coaching!
Buswarrior
Perfect!!! That's what I kind of suspected was the case, but it's good to get confirmation.
Thanks a million,
Seb
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We love our toasty oem otr heat at dash (defroster) & cabin...
Yes, would be most beneficial while driving. Because we didn't want to open any worm cans, we never opened the valves. We were cold back in November and December when driving it, but we didn't/don't know if there are coolant leaks in the heating system. I am very systematically and carefully using and exploring systems.
As far as the heat goes. I was/am pretty sure those big valves in the engine room are closed. My logic, if there is a problem if I open them, I will be cold on the side of the road. If I leave well enough alone and don't touch them I will still be cold, but at least still moving.
Every time I look at or work on something on this big machine I learn more. It's a wonderful adventure, and the help you all give makes it even better.
Thanks
Seb
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As far as the heat goes. I was/am pretty sure those big valves in the engine room are closed. My logic, if there is a problem if I open them, I will be cold on the side of the road. If I leave well enough alone and don't touch them I will still be cold, but at least still moving.
Seb -
So here's what you do if the coach is road-worthy:
Before cutting anything out, or otherwise dismantling the heating system, take the bus out for a short local drive, five to ten miles is sufficient, basically enough to get everything up to operating temperature.
Once you're back in your driveway, shut the engine off for a minute, go back and open the gate valves, then fire up the engine again, put it in fast idle, and go back inside to turn on the heating system, including the defroster. (Don't forget that valve at the floor by your left heel!)
Get out of the coach and start checking all the coolant line's routing, looking for leaks. If you don't find any, well, now you know you've got a defroster that works. If you do find some leaks, you're in your driveway, not cold on the side of the road. KISS principle!!
FWIW & HTH. . . ;)
RJ
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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.
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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.
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Seb -
So here's what you do if the coach is road-worthy:
Before cutting anything out, or otherwise dismantling the heating system, take the bus out for a short local drive, five to ten miles is sufficient, basically enough to get everything up to operating temperature.
Once you're back in your driveway, shut the engine off for a minute, go back and open the gate valves, then fire up the engine again, put it in fast idle, and go back inside to turn on the heating system, including the defroster. (Don't forget that valve at the floor by your left heel!)
Get out of the coach and start checking all the coolant line's routing, looking for leaks. If you don't find any, well, now you know you've got a defroster that works. If you do find some leaks, you're in your driveway, not cold on the side of the road. KISS principle!!
FWIW & HTH. . . ;)
RJ
That sounds like a sound plan of attack.
Thanks
Seb
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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
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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
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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
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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.
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Here is another picture showing the smaller line that allows the fluid to continue through.
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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
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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.
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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
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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
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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
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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
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Here is another picture showing the smaller line that allows the fluid to continue through.
Ok, thanks for the picture. That could help.
Seb
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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