rear or side mount radiator??

[lp5151]

we are looking at a new DP coach. what have you found to be the pros and cons of the rear or side mount radiators?

[Elkhartjim]

About the same as electric vs hydraulic jacks.

[Sixpack98]

The pro's of the side radiator is that it is much easier to change engine belts, alternator and other engine attached accesories, less noise unless engine is equipped with horton fan clutch for rear radiator. Without the horton fan clutch a rear radiator also steals some power which translates in a little more fuel use. Somewhere around .25 to about .5 mpg. With a fan clutch rear and side radiators are about the same. Arguably a side radiator stays cleaner since it is pulling air from the curb side of the coach. I think this was also more relevant when diesels had slobber tubes instead of recirculated crankcases which allowed oil laden bypass to be sucked into the rear radiator. Cleaning a side radiator is also easier but my CAC is stacked on top of the engine radiator and much simplier to keep clean over a sandwiched (back to back CAC and engine radiator) configuration. Also, unless your rear radiator does not have a rock guard, rear mounted radiators are somewhat prone to taking a rock or other road debris which is a very expensive repair. Most rear radiator coaches have rock guards that all but eliminates taking a stone through the radiator.

The cons for side radiator configurations is the initial cost and loss of a compartment. Side radiator fans are hydraulically driven which is initially more expensive and replacing a hydraulic motor is pretty expensive but they are pretty reliable.

I don't think there is much difference in cooling capacity between the two. So, I think the chief advantage of a side radiator is routine maint cost but that is probably offset by the initial cost involved. If you do your own belt and hose replacement the convenience of the side radiator may more than justify the initial cost. I have a side radiator on my DP (ISL 400) and it was a real PITA to change out the engine belt. Next year I will be changing out the radiator hoses and that will be a royal PITA. Both would be much simplier if I had the side radiator.

just my $.02

[Spikester]

Along with what has been said, I think you will tend to find rear radiators used with the various configurations of the Cummins ISB engines, where the Cummins ISC, ISL, ISX, and ISM predominately use side radiators. Believe it has to do with the size/cooling capacity of the radiator for the higher torque engines.

Spike

[Ann n Gene]

Side radiators all but elliminate the overheating problems that used to be common with the rear radiator. In addition, many of the side radiators are mechanically driven NOT necessarily hydraulic driven. As stated above most of the big block cummins will have side radiators. They MAY be on the curb side but many are on the highway side. just my experience.

[Gary RVRoamer]

In my experience, most ISC engines are also rear radiator. Same for the Mercedes diesel.

[denochs]

IMHO, overall, the side radiator is your best option if you consider the longterm benefits.

Dave

[lp5151]

Quote:

Originally Posted by Gary RVRoamer In my experience, most ISC engines are also rear radiator. Same for the Mercedes diesel.

this one is an ISL..425hp Cummins...

[jwinston]

I have read some blogs with issues on rear rads which where damaged by rocks propeling into the rad ...there are some screens that would prevent this.. I have also heard of some very expensive repairs on rear rads due to lack of access to engine componets.. I would think that the side would be better... One down side of side is the cloud of dust that they will kick up on a dirt road.. IMHO James

[Parkerrs]

I have a side radiator and the exhaust pipe is the only thing kicking up dust on a dirt road. I will say from a mechanics standpoint the side radiator would have better cooling in my opinion. It's second benefit is for service access.

After looking at the new model Newmars on a frieghtliner chassis the service access may be a matter of which chassis you have. On my Spartan with side rad. belts, a/c compressor, alternator and filters are all easy from the rear outside. On the new models Frieghtliner moved the rad. to the side but then built a large steel rack holding the hydraulic tank, which is huge in comparisson to mine, all filters other than oil and several other things all where the radiator was. Directly in the rear blocking EASY access to the front engine components. What a dumb engineering move from the perspective of anyone who is actually going to be serviceing the unit. Other coaches with FL chassis may differ but the set-up in the Newmar line this year really turned me off from a serviceability standpoint in comparison to the Spartan side radiator layout.

[Batman_777]

I think you'll get mostly Pro's from owners of side radiators and mostly Pro's from owners of Rear Radiators. Each application have Pro's and Con's.

Side Radiators tend to pick up a lot of junk thrown from the rear wheels.
Side Radiators use 25-75 horsepower to operate
Side Radiators depend solely on the hydraulic driven motor (Something to go wrong)
Side Radiators do allow for improved motor access
Side Radiators do provide improved cooling due to larger radiator area
Rear Radiators use natural air flow under the moving vehicle to assist with cooling
Rear Radiators are protected from road rocks
Rear Radiators are initially less expensive
Rear Radiators are Rad

It really depends upon the unit. If the engineering design calls for the side radiator, then that's the best for it.

[Ann n Gene]

Again, NOT true that all side radiators are hydraulically driven! Mine is mechanically driven from a belt drive. It does NOT throw rocks or create dust (the exhaust DOES throw up the dirt). REALLY doubt that my side radiator uses anywhere near that much hp but have no research to prove that. It is easier to access the engine and it's accessories but more difficult and expensive to work on the fan drive and several pieces in the fan drive to go wrong for sure( including a couple of u joints on mine as well as a belt and pulley. All just my experience, yours may differ.

[Parkerrs]

Quote:

Originally Posted by Batman_777 Rear Radiators use natural air flow under the moving vehicle to assist with cooling Rear Radiators are protected from road rocks .

Not necessarily true. I have no experience with a rear radiator but from posts on this and other boards I have read that they are the one more susceptable to road damage. Also from working with high performance cars and in the aircraft industry at the wind tunnel years ago. The rear of the coach is going to be a nearly dead area as far as air flow, if anything it will be very turbulent rather than directed until a couple of feet past the coach. The rear radiator design is pulling air from underneath the coach after it has passed along under the hot differential, transmission, and engine. It draws this air and forces it through the radiator via the fan. If the fan is direct drive with no clutch, such as a Horton fan clutch, then your horsepower draw will be as much or more than the side set-up.

The side radiator advantage is cooler air flowing down the side of the coach being drawn through the radiator into the engine compartment and both heat from the radiator and engine being exhausted out the back of the coach. Even the hydraulically driven units do not run constantly, or at least not on mine. They use temperature sending units which engage the fan and run it only when necessary just like the Horton fan clutch set up I was speaking of earlier for rear units. The Horton units are extremely common on heavy class 8 trucks.

I've yet to hear pros on a rear radiator other than price, packaging, and maybe the one extra storage bay. The price is worth the trade-off to me personally in service accessability from outside the coach. I also have plenty of storage without that area. Packaging is an area focused on by the manufacturer, the rear radiator is cheaper to build and package.

[lp5151]

there seems to be a bit of concern as to the "debris" that is thrown up by the tires and exhaust that can get sucked into a radiator on a rear mount. but, wouldn't something like the Roadmaster Tow Defender keep most of the big stuff from getting sucked in through the radiator on a rear mount???? if one is towing the bulk of the time and the tow defender is in place, that seems to level the playing field as to debris getting drawn into the radiator. that would leave just the smaller particles ie. dust, etc.????