Did dash air repair alter engine cooling design

[timjet]

I would like some opinions from those in the know about a dash air conditioning repair that has altered (in my opinion) the cooling design of my Cummins ISL, Spartan Chassis, '07 American Tradition with side radiator.

The cooling system as designed by Spartan consists of a radiator stack with the intercooler radiator on top followed by the engine cooling radiator, followed by the hydraulic cooling radiator (steering & fan motor) and on the bottom of the stack the air conditioning condenser.

The dash air conditioner repair shop determined the existing air conditioning condenser was faulty and in an attempt to save me some money and time decided to add an off the shelf air conditioner condenser to the back side of the cooling radiator stack which covers about 50% of the intercooler radiator and about 50% of the engine cooling radiator. They installed it with about an inch or so space between the stack and the new condenser. So airflow across the radiator stack flows from the fan through the radiator stack and then with about an inch space through the air conditioner condenser.

My concern is the airflow through the intercooler and engine cooling radiator will not be sufficient when the engine is under a heavy load, like climbing a 8% grade at 8000 ft. I called Spartan and explained the new installation to them and they could offer me no opinion as to this new installation saying only that if the cooling system is altered they could not say it will work properly. I was not talking to a cooling expert just a general tech. The dash air shop is telling me they have experience in this and the new install is OK.

I'm going to try attaching some pictures of the new install. The original condenser was left in place and the Freon lines rerouted to the new condenser. The original condenser is hard to see in the pictures but is the bottom most radiator. Each of the 4 radiators in the stack has the attachment bolts clearly seen in the pictures.

I would really appreciate some opinions on this new installation as it could save me a ton of money and is more efficient for the air conditioner but I do not want to affect the cooling to the engine or intercooler.

Sorry if you saw this elsewhere I'm trying to get as much exposure as possible.

 

[fairway2002]

Looks like a great job and money saver. When we install super/turbo chargers we cover more of the radiator then yours with no problem. 

 

[Gary RV_Wizard]

Shear guesswork. Without a lengthy & expensive engineering analysis of air flows under various operating conditions, I see no way to prove or disprove how well this works.  My advice would be to just drive it and watch the gauges. Either that, or bite the bullet and replace the OEM a/c condensor.

If it gets a bit warm on that 8% grade, you can always turn off the dash a/c. Probably a good idea anyway. You can always run the house a/c via the genset - we did that anyway with our former American Tradition, whenever it got real hot outside.

 

[timjet]

Yes I think they did a good job of properly installing the off the shelf condenser. But as Gary said there is no way to know without testing whether the cooling to the other units is affected. My concern is reduced air flow. I realize the condenser will add hotter air to the radiator area but it's the reduced air flow to the other units caused by the placement of the condenser that worries me most.
Turning off the dash air will remove some hot air from the area but will not increase the air flow.

Not really sure what to do. As a side note the OEM condenser is probably 2/3 the size of the new one and due to it's location probably gets less air flow than the new one. I will say the dash air with this new condenser is working very well. 

Another thought has occurred to me. Would positing the condenser further away from the existing radiators help. Say increasing the distance between the 2 radiators to about 3 inches from the current 1 inch is possible.

 

[RedandSilver]

I agree - try it and watch the gauges.
Although each trip will be different.  If your worried about it over heating I would think there are a few things that would help.

1. Drive the mountain grades at night.  The temps will be cooler for sure.
2. I couldn't tell if there is a fan behind the radiator but if there is, you could wire a switch so you can turn it on manually.
Before you start climbing a grade turn it on.  IF there is no fan or you didn't want to wire the one there - install an additional fan
somewhere and have that on a switch.  Low air flow is what your afraid you might have, right? So adding any air flow shouldn't hurt.

I'm not sure you will have any problem.  And before I did anything, I would try climbing a grade.  I just hope your not the type
that feels you have to fly up the grades and refuses to follow Truckers going 30-35 mph uphill. 

 

[timjet]

Thanks R & S. No problem going slow up the hills, I just don't want an O/H. Traveling at night is a good option as well as unhooking the toad.
I just wonder if I added a couple of more inches between the condensor and the existing radiators if that would help. Currently they are about an inch apart.

How difficult would it be to add a switch to turn on the fan? Any downside? Fan as I understand it is hydraulic.

 

[Charlie 5320]

Why didn't they just replace the original condenser? That's what should have been done. Why leave something in there that will reduce air flow? If the original condenser is not hooked up remove it.

 

[timjet]

The original condenser would be difficult to remove. It is the lowest radiator in the stack and may require the entire stack to be removed before it could be reached. Also the sealant around the entire stack would have to be removed and replaced. The OEM condenser is $750 and the off the shelf condenser is $250 and probably has a third more area for heat transfer.

If I decide to keep this off the shelf condenser I see no advantage in removing the unused OEM condenser. As mentioned above it would disturb the other radiators and likely cost a couple hundred bucks to remove. The OEM condenser being the bottom most radiator I don't think is causing any reduced air flow by leaving it in place. 

 

[jubileee]

Probably the reason the oem condenser was at the bottom of the stack was to keep the heat it generated from being pulled thru the aftercooler and radiator, unless it's a pusher fan. Anyhow, as mentioned before, dash AC should be off and fan should be on in hard pulls, hot weather, and sometimes when the wind is just wrong. Like all the signs on Baker grade I15 in California. " Shut off AC".  My personal opinion after trying to cool diesel semis in the mountains and desert for over 50 years is that ANY obstruction makes a huge difference in cooling. Even a bug screen. We got along best in the trucking world with engine cooling when the atercooling was air to water and the AC condenser was on the roof. ( except for Cummins disastrous " Optimized Aftercooling" ) Now it's all stacked in front of the radiator.

 

[Utclmjmpr]

  I can hang meat when using the dash air in my American Tradition,, my condenser is located behind the front mounted generator and front axle and has no bearing on cooling the engine with the side radiator.>>>Dan

 

[timjet]

.... my condenser is located behind the front mounted generator and front axle and has no bearing on cooling the engine with the side radiator.>>>Dan

Dan, do you have a fan moving air around the condenser? Was this an aftermarket setup? Could you please post a couple of pictures of your setup, I'm very interested.

 

[Utclmjmpr]

  My coach was built in late 97 and titled as a 98,,in those years American used the Denso system and it has been very reliable over the years. The condenser is mounted just behind the 1200 IFS axle and has an electric fan for cooling, the only thing in front of my GAC is an air to air trans cooler,,never have cooling problems with my side radiator and running the air conditioner has no bearing on the engine heat.>>>Dan