Side or rear mount radiator

[lp5151]

I'm researching diesel pushers. I would like some feedback as to the pros and cons of side-mount radiators.

[Guest BillAdams]

Of all of the things that make a difference between you liking and not liking the motor home you purchase the location of the radiator is not likely to be one of these. Make your buying decision based upon the floor plan first, the cost second, a thousand other things third and the radiator will be in the right location for the coach you choose.

[wolfe10]

Not sure I disagree with Bill's assessment, but you asked for the pros and cons so I will get that started.

Rear Radiator:

Pros: Less expensive to build (no hydraulic system to drive the fan). Most are direct drive, though some have a low/high speed clutch.

Cons: Much quicker to clog the cooling system. Basically a vacuum cleaner for the highway-- the dirt on the road is stirred up by the coach and 6 wheels passing over it. That air then passes over the hot rear axle, hot transmission and hot engine before being pushed by the fan into the CAC (Charge Air Cooler) and radiator. Must be cleaned more often (generally requires accessing from the bedroom/closet and cleaning the front of the CAC with a water hose working inside the fan shroud/between fan blades).

Side Radiator:

Pros: Stays cleaner longer (draws in air from side of coach rather than from underneath). And when it does need cleaning, it is from the side of the coach, not from under the bed/closet laying on your belly.

Engine access is much better-- things like belts, water pumps, alternators, etc are easy/ less expensive to service.

Generally take less HP, as hydraulic systems are easy to control to change the HP used to turn the fan as cooling needs change. Note: some rear radiator coaches also have low/high speed fan clutches.

Cons: More expensive

More complex

More expensive coaches with larger engines tend to have side radiators.

Brett

[tbutler]

Not all side mount radiators are created equal. The challenges of locating them on the side of the coach result in some manufacturers using under-sized radiators. I base this statement on discussions of overheating of engines of the same size as ours. We have had no problem with overheating while people with other manufacturers coaches with the same engine have experienced overheating. Use the search function to read discussions of overheating.

Also, I've known people who found it necessary to construct additional barriers to debris to protect their side radiators while we've never had a problem. The side mount radiator is located behind the rear duals on the coach. This is a high debris location so you should look at the protection from debris from the rear wheels if considering a side mount radiator.

Look at the access provided to the engine on side radiator models. I can crawl into the engine compartment and move all around the engine for inspection, maintenance and cleaning. I like to be able to easily inspect the condition of my engine and find rear radiator models to be less than satisfactory.

[bbnuttmann]

Side radiator is a far better set up. I know that is a short reply, but that is all that is really needed. Get a side one.

[BernieM]

Side mount is soooo much better for the coach itself, maintenance, inspections and actually working on the coach - especially if you are paying for the labor!!!

[DreamBelievers]

The location is determined by the size of the engine.

If your looking at a class a with 500 hp an up, that is a very large powerplant in length, therefor the side mounted style. Large buses have run that style rad for years and never have a problem with them. Hope this clears this up for you.

[wolfe10]

The location is determined by the size of the engine.

If your looking at a class a with 500 hp an up, that is a very large powerplant in length, therefor the side mounted style. Large buses have run that style rad for years and never have a problem with them. Hope this clears this up for you.

Not necessarily true. It is as related to price point of the coach as to engine size/length. Sure, larger engines usually come with side radiators, but are also generally found in higher end coaches.

But, there are plenty of exceptions to the "engine size" rule:

Our 250 HP 1993 Foretravel for example has a side radiator.

There are a lot of 400 HP rear radiator lower end coaches out there.

Side radiator coaches are more costly to build, so more price point sensitive brands/models are more likely to have rear radiators, whether 250 or 400 HP.

Brett

[rgrussell76@yahoo.com]

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

Side Radiators have more initial cost

Side Radiators eat up potential storage

Side Radiators add more weight to one side of coach

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

[rorr1821]

I have owned both the side and rear radiator motorhomes. Here is my assessment of the pro's and con's.

Rear radiator: It is more difficult to work on the engine because the radiator blocks the engine from the rear. Access always must be done from inside bedroom area to reach the top of the engine or to service the turbo. Oil changes and coolant filter access is done from the outside under the motorhome.

General the cooling fan is a direct drive. So the more RPM's the faster the fan turns. However, there is a solution which works great and provides about 1 MPG saving in fuel. In doing so it gives you more power to the wheels. I am familiar with the Horton clutch fan which is connected with the engine computer and only engages when your engine reaches a pre-determined temperature. Otherwise it turns freely vary similar to a clutch fan on older cars (newer cars have electric fans which are a different animal). I have had the Horton fan on two motorhomes and it does work as stated. A rear radiator can be prone to sucking up a stone from the road. You can fabrication a wire shield to minimize the chances of sucking a stone into the fan and through the radiator. I have been to Alaska and put many miles on rear radiator motorhome's and have not had a problem.

Side radiator: Even though it was posted that a side radiator uses less power, I disagree. The hydraulic pump's that I have seen are powered from the engine. I was told by Cummins that it took somewhere between 25 and 30 hp from the engine to turn this pump. Keep in mine it is working all the time. The side radiator is easier to service and makes accessing the engine much easier. It seem to me the side radiator motorhome I had drew the air from under the unit pushed it out the side. If that is correct I would think you have the same chance of picking up a stone and putting it through the radiator. I have had to clean both rear and side radiators. I do not believe either version is that difficult to clean.

Generally you will pay more for a motorhome with a side radiator. You have more parts that could go bad (pump, hydraulic motor, hydraulic hoses, valves, etc)

The bottom line do not buy a motorhome with the radiator being the decision point. Floor plan, size, how are you going to use it, quality of construction, and reputation of the manufacture should be your guide in making an informed decision in my opinion.

Several manufactures have gone out of business leaving owners with no warranty and one manufacture went chapter 11 then 7 and then was bought out still leaving owners with no warranty even though they are making motorhomes today under almost the same name, interesting!.

These are my thoughts.

Ray

[wolfe10]

While all opinions are welcome, let's keep the facts straight.

While there may be side radiator hydraulic systems that run 100% of the time, the VAST majority of these systems are two speed or variable speed. So, their HP demand for running the cooling fan(s) is normally proportional to cooling needs.

The vast majority of rear radiator coaches are direct drive, so the fan takes the same HP when it is 20 degrees F as when it is 100 degrees F. The Horton Fan Clutch is an option that turns the rear radiator from direct drive to a two speed fan with low speed taking less HP just as stated by ror1821.

I have never seen a side radiator that sucked from the engine room and exhausted the side. If that is what yours does, PLEASE CONTACT YOUR CHASSIS MAKER IMMEDIATELY, you likely have the hydraulic lines to the fan(s) hooked up backwards. Normal air flow is from the side of the coach through the CAC, then radiator with the fan(s) sucking the air into the engine room and exhausting under the coach or through the back.

Brett