Bus Heat Coolant source on L10, M11, ISM?

Brian Diehl · March 28, 2007, 08:44:22 AM

For those of you with experience with the Cummins L10, M11, ISM line of engines I have the following question:

Where do I take the "hot" coolant from on the engine to send to the bus heater core? The truck setup I got this from used a 5/8" outlet from the head. I just don't see how that 5/8" outlet is enough for the bus heater core flow requirements. So, I wondering where others have connected into the coolant system.

Thoughts?

skipn · March 28, 2007, 09:06:48 AM

Brian,

Radiator hose from the bottom of the passenger side radiator to the tranny cooler to the bus heater core. There is a cross-over
for when the line to the heater core is shut off. The coolant has added heat up from the tranny cooler instead of a straight shot from
the radiator.

If you wish you could route the feed line to the radiator to the heater core first and then to the radiator. You still will probably need
a shunt for when the line to the heater core is shut off.

Skip

Brian Diehl · March 28, 2007, 09:31:01 AM

Quote from: skipn on March 28, 2007, 09:06:48 AM
Brian,

Radiator hose from the bottom of the passenger side radiator to the tranny cooler to the bus heater core.

Skip

Skip, this sounds like the heater core return line. Where is the supply taken off the engine?

Tom Y · March 28, 2007, 09:36:32 AM

Brian, My L10 has a 1 inch outlet by the left front (thermostat) and a 1 inch inlet on the left rear by the block heater. Tom

skipn · March 28, 2007, 09:44:09 AM

Brian,

If you like I'll get you pictures tonight and post them. The heater core return to the engine is on the driverside to the water pump
intake.

Either that Or I am totally backwards (wouldn't be the first time) I will double check anyways.

Skip

skipn · March 28, 2007, 04:40:45 PM

Brian,

Here are some. If possible maybe Tom Y can get you some pictures of his.
It is probably a cleaner job mine looks a little funcky to me. I'll have to think
on this. Like Tom said the return from the heater core ties into the back/side
drivers side of the block.

The thing is the Y that goes to the tranny cooler and the other goes to the water pump where
the otherside radiator return is.

Hope this helps

Skip

NJT 5573 · March 28, 2007, 09:48:21 PM

The hotest water comes out of the water manifold on top of the motor so that is pressure out.

Brian Diehl · March 29, 2007, 06:05:07 AM

Thanks Skip. I appreciate the help and the pictures!

Tom, could you get me a picture of the spot on the engine where you are getting the 1" outlet to the heater core from by the thermostat? I want to make sure I'm picturing it in my head correctly and correlating it to what I see on my engine.

Thanks!

Tom Y · March 29, 2007, 06:05:57 PM

Brian, Hope this helps. The 3/4 NPT ( pipe plug ) on the lower left is where mine comes from. The part below goes to the water pump, the one to the upper right goes to the rad. This is a thermostat housing I had, mine is so congested there you would not see much. Tom Y

Brian Diehl · March 30, 2007, 06:10:07 AM

Thank you Tom! The picture helps a lot.

skipn · March 30, 2007, 07:57:18 AM

Brian,
Thanks, by you asking questions I really had to figure out how my coolant flows.

So an open question....
Since I have 2 crossovers to the waterpump intake side of the circuit which can really reduce the flow to the coach heater core.
To increase flow would it be better to?
1. on the heater core line put in a inline radiator pump like what Meziere makes 1" in 1" out 55GPM 12 volt ~6 amp turn on when temp valve active
2. on the tranny cooler cross over put in a normally open 1" valve and when the heater is on at the temp valve the normally open would close
3. Just don't worry about it.
and of coarse all the whys and wherefores is what I am looking for.
Thanks

Skip

Brian Diehl · March 30, 2007, 09:12:06 AM

Hi Skip,

Question: Do you have problems with the current heater output? If yes, then ...

1) I like this the best as you will get "For sure" flow to the heater core. However, the temperature control valve is Normally Open. So, when the thermostat is calling for heat you will have no voltage to the temp. valve. You could use a normally closed relay to turn on the pump when the voltage is removed from the water control valve. When voltage is applied to the water control valve to stop water flow in the core it would also break the relay (now on) contacts and turn off the water pump to the core.

2) I'm not sure how this would exactly work ... is this an electrically controlled water valve? I guess I would rather not have to mess with the coolant flow to the transmission cooler.

3) If the answer to my question was "no", then yes .... don't worry about it.

skipn · March 30, 2007, 09:53:08 AM

Yep,
With everything wide open.
Radiator 150
Heater core ~90
Defrost core ~70

Granted when I get the Radiator shutters working properly My start to finish temps will be higher but the drop off is what I am trying to cure
by higher flow. In this part of the country (as yours) there are times when this would make for very unpleasant travelling. Years ago we spent
Christmas in Letheridge -28F and my powerstroke with cardboard on the rad couldn't keep the windows defrosted. I never want to go through that
again. ok so I'm dreaming a little.......

Skip

Brian Diehl · March 30, 2007, 10:06:13 AM

Skip,
I think two problems are happening assuming your temperature guages are correct.
1) I think the 4 stroke is just not putting out that much heat (efficiency).
2) I think whatever heat you getting out of it is being removed by the bus heater core (assuming the engine thermostat is working correctly).

Most 4 stroke equipped buses are delivered with a Webasto or Proheat diesel based coolant heater in the heater core loop to provide enough heat to keep the passengers warm. I think I'm going to find I will not have enough waste heat to keep my bus warm in cold weather and will need to use my webasto hydronic heating system to keep up with the heat demands while going down the road.

Tom Y · April 08, 2007, 05:59:35 AM

Brian, Let me start with HAPPY EASTER may we not forget what it means. I was monkeying with my bus waiting for my family to wake. I have the rear line marked hot, and the front one at the thermostat housing marked return. Now I am not sure which is which and hope I did not lead you wrong. But you know what they say about getting what you pay for. I also have some 6 inch air lines and elbow for intake air if you can use you can have for shipping. Mostly junk and will be thrown. Tom Y