Community Forums

2InAlabama · 01-07-2012, 12:29 PM

Newbie DP owner here.

I have seen quite a number of posts indicating a preference for side radiators, but no reason given for the preference. Why is the side radiator more preferred over the rear one?

Dutch Star Don · 01-07-2012, 12:56 PM

Because its usually attached to a nicer motorhome!

Joking aside, the nicer motor homes have more features, are heavier and have larger engines. The side radiators cool better, but do take some additional horsepower to run the hydraulic pump that spins them.

Side radiator coaches also give greater engine access, allowing you to open the back doors and walk into the engine compartment. Most anyone who services their own coach will tell you that their next coach would be a side radiator.

Smitty77 · 01-07-2012, 01:15 PM

X2 - If buying, and everything else about the rig is what you want, don't let rear radiator keep you from buying one. Just be aware of the added restrictions, and more often cleaning requirements of rear vs side.

If possible, and shopping, give higher points to a side radiator coach, over a rear. Same thing with Compression over Pac Brake. Raised rail vs non raised rail construction is not as clear cut, but raised will usually yield larger pass thru storage bays, etc., etc.

Best of luck. The key, is to get a coach you like - and have some fun!
Smitty

Mr_D · 01-07-2012, 01:51 PM

Quote:

Originally Posted by Diplomat Don

Because its usually attached to a nicer motorhome!

Joking aside, the nicer motor homes have more features, are heavier and have larger engines. The side radiators cool better, but do take some additional horsepower to run the hydraulic pump that spins them.

Side radiators cost a lot more than rear ones so they tend to be used on more expensive rigs. Also with the radiators and fan off to the side the the body can be shorter.

Since the hyd pump can be deactivated when not needed I don't thank the above holds true. A rear mounted fan is usually running all the time so it takes HP every minute the engine is running, the hyd one may shut off when not needed.

The access is much better too. I can change my belts in just a few minutes. In fact it takes me longer to find the tools than to actually do the change. Everything is so much more accessible with a side radiator too.

Mike Canter · 01-07-2012, 04:11 PM

My hydraulic pump that runs the fan comes off a PTO from the side of the Allison transmission. I have another pump that runs the power steering and stuff. The ISM-500 uses just a pump off the motor but either way they run all the time. They do not turn off and on.
. Not sure which uses more power/fuel, the big fan being run by a fan belt off the motor or the hydraulic pump. You got to have a hydraulic pump anyhow to run the power steering even when you have a engine driven fan so my guess is the side mounted radiator without the belt driven fan gets better mileage. I sure like being able to get to everything without having to lift up the bed or floor.

frederick w · 01-07-2012, 04:21 PM

I noticed a side radiator on a 98 Monaco. It had a Spartan chassis.

Are side radiators availble on all DP chassis? Or just on certain
chassis. Say years, 95-98.

Thanks

Lault · 01-07-2012, 04:21 PM

The Cummings rear rad. fan does turn off if not needed. I hear it turn on, off and can look under the coach and see it is turning at very little RPM, slow enough to see the blades.

Pusherman · 01-07-2012, 06:11 PM

The fundamental advantage of a side-radiator over a rear-radiator cooling setup is that the rear-radiator engine tends to pull a lot of road gunk and debris up into the radiator while travleing, which means it tends to get a lot dirtier in this configuration.

Generally speaking, side-radiator cooling systems are usually used on larger diesel engines, around 400 hp+. Spartan used the side-radiator setup on some of the earlier engines with 350 hp engines, but these days mostly the larger engines use the side radiator configuration.

I don't think there are any advantages of one over the other regarding cooling. Most the 300-350 HP coaches use rear radiators, and they perform just fine. Maintenance on these coaches must include cleaning the rear radiator periodically.

JManatee · 01-07-2012, 06:14 PM

Quote:

Originally Posted by Lault

The Cummings rear rad. fan does turn off if not needed. I hear it turn on, off and can look under the coach and see it is turning at very little RPM, slow enough to see the blades.

Not sure all cummins come with this ... Mine spins all the time.

Mike Canter · 01-07-2012, 06:32 PM

My previous rear radiater MH's fan didn't run much at idle but I lifted the bed several times going down the highway and it was always running.

Pusherman, you may have hit the nail on the head on motor size. I know my Detroit and the Cummins ISM are way too long to put a cooling fan and radiator/CAC in the back of it. It is probably the engine's physical length that really effects the design. My MH would have to be over 45' long to do it. I bet it would be 47-48' long if you added a rear radiator.

deandec · 01-08-2012, 11:44 AM

Quote:

Originally Posted by frederick w

I noticed a side radiator on a 98 Monaco. It had a Spartan chassis.

Are side radiators availble on all DP chassis? Or just on certain
chassis. Say years, 95-98.

Thanks

Side radiators were used on the more expensive rigs of that era. Our 95 Country Coach on a Gillig Bus chassis is a side radiator with a 300 hp Cummins engine.

yudamann · 01-09-2012, 10:34 PM

Side radiators will provide cleaner surface on toad when towing. Less dirt and oil blown onto toad with side radiator configuration.

Mr_D · 01-09-2012, 11:27 PM

Both our DSDP's have been side radiators. One a 2000 FL chassis with 300 HP CAT 3126 and now the 2002 Spartan MM with 350 HP ISC.

Kind of disproves a few theories here as to when they are used.

ga traveler · 01-10-2012, 09:41 AM

According to the engineers I have talked to at the Louisville Show. #1 advantage of side radiator Ease of access to the engine. #2 less problems with junk clogging the radiator. (Sludge from breather mixed with dirt and trash kicked up by rear tires.) the con is the side radiator is in the slipstream of air and tends to keep air from going into the radiator.(this is why you see some side radiators with a scoop added. The advantage of the rear radiator is it is at the rear and there is a vacumn at the rear of the coach that helps pull the air through the radiator. The con is it is much harder to access the eng. and belts.