Using coach radiator to cool genset

[DrivingMissLazy]

I originally posted this on another board but thought it should possibly be here also.

First I would like to say that anyone that gets a chance to see Hal St Clair's coach is in for an eye opening experience.

The converters that did DML (predecessors of Marathon Coach) integrated the genset cooling into the engine coolant system along with the Webasto heating system and the hot water (really cold water) heating system. After I got the bugs out, it worked great, and if I were to build another coach that is definitely the way I would go.

One of the major problems I experienced was that immediately after I bought the conversion, I took it to a shop in Tucson to upgrade the 6V92 to an 8V92. In addition to screwing me on the price and many other problems, they installed a larger radiator and then crimped the water outlet hose from the genset going to the radiator.

This all happened before the days of the internet, the bus boards and Bus Conversions Magazine.

The first problem I experienced was the genset would shut down on over temperature after operating for 30 minutes of so while parked out in the desert.

The first thing I did to try and solve this was to install an electric water pump in the 1 inch water line from the genset to the radiator. Unfortunately this did little good.

I then discovered the crimped hose, and after re-routing it, the condition improved considerably but the system would still overheat after a couple of hours.

I then installed two 16 inch electric automotive radiator fans on the coach radiator to push cool air thru the radiator. These fans came with a thermostat control that could be slipped into the fins of the radiator. Additionally I installed a yellow indicator light in the dash of the coach to indicate when the fans were actually operating.

That totally solved the overheating problem with the genset and I operated 15 years like that. It also helped with the overheating problem I had with the main engine. In hot climates during the summer and while pushing the coach hard, or while climbing grades, the yellow indicator light would come on telling me that the auxiliary fans were operating.

Regardless of what some have said in previous posts, the auxiliary fans do help in cooling the main engine. Also beware of the “nervous nellies” who fear a few extra plumbing connections will lead to premature failure. If it is done properly, there is no additional danger.

This also eliminated the requirement to have a separate surge tank as well as two different coolant systems. Always had plenty of hot water from the engine heat or the Webasto heat and always a warm bus.

After I got the few bugs out I would not have changed anything.
Richard

[brojcol]

Richard,

Awesome post!  You wouldn't happen to have pictures would you?

[DrivingMissLazy]

Richard,

Awesome post!  You wouldn't happen to have pictures would you?

Thanks. Sorry,  I no longer have the coach. She is currently sitting down in Texas getting re-done due to a fire in a heater under the bed. Should be about ready to get back on the road again.
Richard

[TomC]

That's great if you have the radiator capacity.  But many of us, me included have increased the horsepower, one way or another, and have increased the radiators to the largest that will fit in the hole made for them.  I for one use the separate radiator that came with the genset from Powertech with a two speed 1/2hp belt driven squirrel cage blower pulling the air over the radiator then out the side.  High for during the day and low for quiet night time use.  Also, have installed a hayden transcooler to supplement the shell cooler.  Transits were designed to go stop to stop-which makes for plenty of cool down time in between.  Whereas highway buses are made for high speed continuous use.  If you have the radiator capacity, using one radiator works well.  But if not, start separating out items that may heat up the radiator to lessen its' load.  Living out west where we get over 100 degree weather regularly with the highest passes in the nation presents alot more challenges than anything east of Colorado.  Even with the high humidity in the east, it rarely gets above 100 degrees.  Good Luck, TomC

[DrivingMissLazy]

My situation was that I really did not have sufficient radiator capacity for when I installed the 8V92. Of course, I did not know that at the time. Neither did I do the actual installation of the genset plumbed thru the coach radiator.

When I had the new engine installed, I had the shop put in (supposedly)  the largest radiator that would fit. Even with the genset not running, I sometimes had overheating problems while driving thru the western mountains. I found that easing up on the go pedal helped solve this problem.

With the genset running and the auxiliary fans installed, I never really noticed any difference in the over temperature problem. I did add misters that did solve any remaining existing problems.

As I stated in the previous post, If I had it to do over, I would do it the same way. The convenience of one coolant system, especially in colder weather could not be beat.
Richard

That's great if you have the radiator capacity.  But many of us, me included have increased the horsepower, one way or another, and have increased the radiators to the largest that will fit in the hole made for them.  I for one use the separate radiator that came with the genset from Powertech with a two speed 1/2hp belt driven squirrel cage blower pulling the air over the radiator then out the side.  High for during the day and low for quiet night time use.  Also, have installed a hayden transcooler to supplement the shell cooler.  Transits were designed to go stop to stop-which makes for plenty of cool down time in between.  Whereas highway buses are made for high speed continuous use.  If you have the radiator capacity, using one radiator works well.  But if not, start separating out items that may heat up the radiator to lessen its' load.  Living out west where we get over 100 degree weather regularly with the highest passes in the nation presents alot more challenges than anything east of Colorado.  Even with the high humidity in the east, it rarely gets above 100 degrees.  Good Luck, TomC

[Bob Belter]

Ahoy, Richard,

On my -01 Eagle with a 12kw genset I RELUCTANTLY connected my genset to the engine cooling system because the independent radiator which I had space for was marginal.

I'm an airplane guy, and in airplanes NO engine ever has any notion that there is another engine anywhere around.

I don't need to run my genset underway, and I decided that the risk of a leak in the not - operating genset causing an engine coolant fault was low.  I also have two different low coolant warning systems.  Furthur, I have shut-offs to the genset, and there is lots of fresh water aboard to replenish a loss in order to get home.

I have two automotive cooling fans (Mercedes) against the radiator on a thermostat.  After a while, they come on and operate for maybe 40 or 50 seconds about every five minutes.

 Enjoy /s/ Bob