sprayer for rear radiator

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sprayer for rear radiator

June 11, 2016, 04:42:18 pm

This is the time of year to write about how to install a radiator sprayer, cuz I'm sure it's on your mind if you're driving your coach up long steep grades in hot weather. If you have a rear radiator it is possible to install a sprayer, but it's a little more difficult than with a side radiator. What I did was install a ring of plastic tubing around the fan on the shroud, with the water spraying on the fan blades. The fan distributes the water over the entire radiator as it blows air through. I had to drill some small holes in the metal shroud to attach clips that hold the plastic tubing in place, but those are the only holes I drilled in the whole coach for this entire project. I used zip ties to secure the plastic tubing all the way back to the radiator. I didn't buy fogger jets. I drilled tiny orifice holes in the plastic tubing ring with the smallest drill bit I could find. I think I drilled about 30 holes, which turned out to be too many probably, but eventually they'll start to plug up with calcium maybe (?) I suggest you drill about 20 holes, or fewer, evenly spaced around the ring, spraying directly onto the fan blades. This depends on how small your drill bit is of course. If you need to add more holes for slightly higher water flow later you can. I'd add the holes one at a time though until you get it just right. It would be easier to increase water flow later than to decrease it if you know what I mean. I made my plastic tubing ring fill from the bottom so I could easily drain it in the winter to avoid freezing. I control the flow of water with a normally closed 12 volt DC solenoid valve. The water comes from the utility bay where there's a fresh water hose bib to flush the black water tank with a sprayer built into the tank. This tank sprayer seems to be fairly useless in my experience, so I'm using the water for a much more valuable purpose now. I'm told this black water tank sprayer isn't on all coaches though. Obviously I leave my fresh water pump turned on while driving and have plenty of fresh water in the tank to spray on the radiator. I control the solenoid with the "aux pump" circuit, because it isn't used in the summer when I need the sprayer. I unplugged the aux pump relay, which is located in the small door behind the dual wheels on the driver's side. The aux pump relay is the one to the rear of the coach as I look in that small door at the isolator panel. I plugged the solenoid valve into the terminal on the left side of the socket that I unplugged from the aux pump relay. Beware that my coach may not be wired the same way yours is, so please verify this stuff through testing on your coach. I installed the solenoid valve inside that same little door where the isolator panel is so it's easy to drain the valve and all the tubing to prevent freezing in winter, which it didn't because I installed this sprayer last summer and it survived freezing temperatures all winter. With this radiator sprayer I can climb the longest steepest grades in the hottest weather with the accelerator flat to the floor all the way up. It actually works better than I expected and I need to be careful not to overcool. I've climbed over the continental divide in Colorado ...at 13,000' if I remember correctly, climbed out the west entrance of Death Valley national park, climbed many long steep grades in Aridzona at temperatures up to 119 degrees, with the accelerator flat to the floor all the way up. I've used as much as 25-50 gallons of water in a day's driving before, but I have a 100 gallon water tank so that's okay. I'm actually losing a lot of weight as I use up the water so my performance increases as the day goes on. As I'm climbing a grade in hot weather I watch my temperature gauge and turn on the aux pump switch if the temperature gets much above 200 degrees. I immediately turn off the aux pump switch as soon as I see the temperature needle start to go down to prevent overcooling. This is easily the best modification I've ever made to my coach. Without it I have to slow down to a crawl to avoid overheating on long steep grades in hot weather. With this modification I can outrun most cars climbing the continental divide, even on a hot day. I can easily climb out of Death Valley, which is famous for burning up cars. If you're gonna do this modification let me know and I'll post photos and answer specific questions. If you're one of those people who seldom (or never) goes anywhere but wants to speculate on all the problems I didn't have please spare me. I'm writing this from a year of actual experience. It works... I'm kinda surprised Foretravel didn't install a radiator sprayer from the factory... Hope this helps someone who can't get their coach to function in the heat.

Re: sprayer for rear radiator

Reply #1 – June 11, 2016, 05:10:41 pm

Great idea. Water has also been used (direct into the intake) for high pressure turbocharged gas engines. I bought a fan for the patio that has a house pressure round spray ring on it that would be pants in this application. (it was far to drippy for the porch and just got everything wet)

But you know folks will say thus: Why in the world did you stay in Az until it was 119?

Re: sprayer for rear radiator

Reply #2 – June 11, 2016, 05:45:45 pm

Scott,

Awesome write up, congrats on the upgrade!

You have come a long way from the post where you wanted to trade this fine (but broken) coach for a used class C

Keep it up!

Re: sprayer for rear radiator

Reply #3 – June 11, 2016, 06:37:49 pm

Quote from Bigdog"But you know folks will say thus: Why in the world did you stay in Az until it was 119? "----

Bigdog, why not as it is DRY heat and the restaurants and drinks are cheap!!
JohnH

Re: sprayer for rear radiator

Reply #4 – June 11, 2016, 07:06:05 pm

Seeing as how I have lived there. Even with "dry heat" 119 is still bloody hot.

Re: sprayer for rear radiator

Reply #5 – June 11, 2016, 07:10:15 pm

I work for the national park service and I was stationed at Lee's Ferry during the hottest part of last summer, which was the motivating factor for this modification... and it worked!

Re: sprayer for rear radiator

Reply #6 – June 11, 2016, 07:12:09 pm

Quote from: bigdog – June 11, 2016, 07:06:05 pm

Seeing as how I have lived there. Even with "dry heat" 119 is still bloody hot.

Got that right, even up here at 5K, it was 100. That being said, we only ran the rear air to keep the noise down up front. The coach is so well insulated and the Carrier ac works so well, we were warm, but no suffering!

Re: sprayer for rear radiator

Reply #7 – June 11, 2016, 07:37:20 pm

Long term effects of the spraying is mineral deposits plugging radiator,that has been tried on industrial compressors and
generators,it works great but the water leaves deposits.

Re: sprayer for rear radiator

Reply #8 – June 11, 2016, 07:51:39 pm

Using windshield fluid does not clog injectors nor leave harmful deposits. I used it for years on my MCI with both the 12V-71 and 8V-92 at over 600 hp with happy results.

Re: sprayer for rear radiator

Reply #9 – June 11, 2016, 09:56:04 pm

Does a rear radiator rig run hotter than a side radiator rig?? Our side radiator rig has never had a heating problem even on long pulls up steep grades. I try not to push it hard up these grades either and all seems to perform well. Have a great day ---- Fritz

Re: sprayer for rear radiator

Reply #10 – June 12, 2016, 12:09:25 am

Did this on my side radiator 6v92 a couple of years ago. Same as you used 1/4" plastic tubing run directly from my water pump. Used a sharkbite tee on the pressure side with a sharkbite refrigerator ice maker valve to control how much water it sent to the "mister". Wired in a NC solenoid with a switch at the dash. Simple cheap effective. I stay in the mountains whenever possible. My redneck engineered desert cooler has saved my butt many times.

see ya
ken

Re: sprayer for rear radiator

Reply #11 – June 12, 2016, 01:45:27 am

Would it also work on the front radiator for the air condition. Or the CAC for that matter. Seems to me water sprayed on any of that stuff would make cooling more effective.

When it's HOT I usualy spray water on the family car radiator to jump start the air conditioning before we leave to go somewhere.

Re: sprayer for rear radiator

Reply #12 – June 12, 2016, 02:08:04 pm

Seeing as how I have lived there. Even with "dry heat" 119 is still bloody hot. (Bigdog quote)

agree as I used to own a house in Tempe while going down from Vancouver BC for golf trips. Sit by the pool at over 50c with a bottle of wine. They closed Sky Harbour Airport for 1 day as tarmac was melting and aircraft tyres got stuck!!
JohnH

Re: sprayer for rear radiator

Reply #13 – June 12, 2016, 03:40:43 pm

I don't quite know how to respond to the minerals on the radiator thingy. I only sprayed maybe a couple hundred gallons of drinking water on my radiator in a year. It'll be about a gazillion years before any minerals build up on my radiator, and if they do it's probably from dirty water splashing up from the road. I don't have a 55 gallon drum of windshield washer fluid so I don't really know how to respond to that either. This idea really works folks. I've tested it for a full year myself personally in all sorts of situations. The only problem I have is it works a little too well cuz I got carried away and drilled a few too many spray orifices. Not sure about side radiator coaches because I've never owned one. Based on what I've read here it seems like a side radiator sprayer would be easier to install because it's on the outside of the coach. The only operational difference I can think of would be if some of the jets clogged up it might make for an uneven spray pattern and less coverage on a side radiator because the fan pulls the water through the radiator. On a rear radiator you spray the water on the fan and the spinning fan disperses the water all over the entire radiator even if some of the jets are plugged. I also kinda wonder if strong crosswinds might affect spray patterns on the side radiator with the sprayer on the outside of the coach in the wind... but I don't know this, I'm just wondering. I think a sprayer would help any coil that is hot enough to vaporize the water, including the AC condenser coil. I haven't done this personally but I know other people have, and it works. I don't have any need to cool my condenser because it's out front in the wind and it cools great even at 119 degrees! (pant, pant) This brings up a point that I hadn't previously considered. On some of the side radiator coaches I think the condenser is in front of the radiator. I wonder if the water will vaporize on the condenser instead of the radiator, which wouldn't help the radiator much... so in that case do you have to install the sprayer between the condenser and the radiator to cool the radiator? ...I dunno, I've never owned a side radiator coach... Sorry to answer questions with more questions

Re: sprayer for rear radiator

Reply #14 – June 12, 2016, 03:43:22 pm

Quote from: kenhat – June 12, 2016, 12:09:25 am

My redneck engineered desert cooler has saved my butt many times.

Seems to me that is only the 40 footers or coaches with rear radiators that have cooling problems. We just came from Phoenix to Flagstaff the other day in 100 + degree temps up I-17, one of the worst climbs in the SW, and the temp gauge climbed, but not worrysome. I just had a thought; I've looked in KENHAT's compartments: he has more stuff crammed in there than an Ace Hardware stocks. I've heard that Dori collects rocks, as well. Could extra weight contribute to the need for aux cooling?

Re: sprayer for rear radiator

Reply #15 – June 12, 2016, 04:20:40 pm

Much of the cooling problem is caused by the ATEC computer slipping the torque converter and making a huge amount of heat. I don't know if the 6 speed Allison does that but the 4 speed Allison does it all the time. If you don't have a sprayer you can keep your rig from overheating by paying close attention to your tachometer and never letting your torque converter slip. Learn to recognize the difference between the tachometer readings of a "real" shift and just splitting a shift by slipping the torque converter. Look at your transmission gauge to see if it's climbing, which it will be if the torque converter is slipping. Shift into a lower gear immediately if the torque converter starts to slip. Beware that it can slip in any gear, which may go against what you've read here on this forum. My 4 speed can lock up in any gear, it even splits 1st gear between slipping and locked up. I don't want to start an argument about that. If you don't believe me that's fine and I'm okay with that. I know one spot where it splits 1st gear every time I drive over it and I watch the tachometer as it splits first gear up and down while I've got it in 1st gear manually. This is really important when you're climbing very steep grades found in the rocky mountains. On super steep grades you can't upshift without the ATEC computer splitting the shift, so you're stuck in that gear all the way to the top of the grade if you're close to overheating, so basically you still need a sprayer to climb those grades any faster than a crawl, but it's very educational to try it without a sprayer just once.

Re: sprayer for rear radiator

Reply #16 – June 12, 2016, 04:36:29 pm

Maybe Foretravel slightly undersized the radiators for the Detriots. I seem to see a great many post about heating problems on these 92 series engines. My 1990 Unihome with 3208T Cat mechanically injected engine (no engine computer) and 4 speed Allison trans with Atlas radiator never gets over 160 degrees no mater how hard you run it or how steep the climb. It is a rear radiator set up. Just curious, any other folks with the 3208T set up experience any heating problems, or use a water spray system?

Re: sprayer for rear radiator

Reply #17 – June 12, 2016, 06:16:07 pm

Yes, the 2 stroke Detroits are much harder to cool than the 4 stroke engines. I like the2 stroke engines, and just have to do what is needed to keep them cool when you turn up the horsepower. I ran a 4' Wide X 5' Tall with 6 rows , worked good up to 500 hp, then added the sprayer to keep raising the power. The setup was a pusher setup, 5' pusher fan across the rear, set it up with a oil temp. thermostat on the fan. Level road, cool weather the fan was not engaged, rare.
Enjoy

Re: sprayer for rear radiator

Reply #18 – June 12, 2016, 08:44:27 pm

I think only the two cycle engines had an ATEC computer in those years. It's the ATEC computer that's causing most of the overheating by slipping the torque converter on every uphill grade instead of doing a "real" shift. I guess the computer wants precise control of engine rpm, possibly for cleaner emissions or higher fuel efficiency? I doubt the non computerized transmissions slip the torque converter as much. I doubt the 6 speed transmissions slip the torque converter as much either. It's only a problem on long steep grades out west in hot weather. When I drive my coach back east I never have a problem because the steep grades aren't long enough to cause overheating. In the rocky mountains some of the steep climbs go on and on for 20 miles. Now that I have the sprayer I don't worry about the torque converter slipping, I just let the ATEC computer do its thing. It's nice to know how to avoid slipping the torque converter in case I ever run out of water or have some problem with my sprayer though.

Re: sprayer for rear radiator

Reply #19 – June 12, 2016, 11:29:31 pm

Quote from: mike leary – June 12, 2016, 03:43:22 pm

Could extra weight contribute to the need for aux cooling?

Yes!

see ya
ken

Re: sprayer for rear radiator

Reply #20 – June 12, 2016, 11:43:03 pm

Quote from: Kemahjohn – June 12, 2016, 04:36:29 pm

Maybe Foretravel slightly undersized the radiators for the Detriots.

The 6v92 is a 2 stroke so it fires on every stroke. This causes twice a much heat. (ok probably not twice but close) Foretravel went to the side radiator when they bumped the HP to 350. There wasn't enough room to mount a radiator big enough to handle the extra heat on the rear. The single fan side mounted radiator (may apply to twin fan side mounted radiator but since I don't have one can't speak for them) is "undersized" but only because there isn't room to mount a bigger one.

I could drop my car and empty my bays but I'll just use my fresh water tank to supplement the cooling on the few big hills & really hot days where I need it. DWMYH!

see ya
ken

Re: sprayer for rear radiator

Reply #21 – June 13, 2016, 12:22:48 am

Quote from: RRadio – June 12, 2016, 04:20:40 pm

Much of the cooling problem is caused by the ATEC computer slipping the torque converter and making a huge amount of heat. I don't know if the 6 speed Allison does that but the 4 speed Allison does it all the time.

Another contributing issue is that the transmission is water cooled. So if the engine temp is above the transmission temp the transmission oil is being heated by the engine coolant instead of being cooled. The transmission oil acts as a heat sink until the transmission oil is the same temp (or higher) as the engine coolant. At that point the radiator fan has to work twice as hard to cool down both the engine and the transmission. It baffled me why it took so much longer to cool down than to heat up until I figured this out. On the steeps low gears and high rpms are the 6v92's friend.

see ya
ken

Re: sprayer for rear radiator

Reply #22 – June 13, 2016, 12:23:58 am

Without a water sprayer, my old Revcon, would immediately start overheating on the smallest of hills. With the water on, cool as can be on any hill.

Re: sprayer for rear radiator

Reply #23 – June 13, 2016, 08:48:32 am

I open the driver's side access door, look in & down and I see a "radiator" mounted horizontally, with a large electric fan on top, and hoses going to the Allison transmission. Was this standard? Or something ordered special or aftermarket addon?

Re: sprayer for rear radiator

Reply #24 – June 13, 2016, 10:59:56 am

Quote from: nitehawk – June 13, 2016, 08:48:32 am

I open the driver's side access door, look in & down and I see a "radiator" mounted horizontally, with a large electric fan on top, and hoses going to the Allison transmission. Was this standard? Or something ordered special or aftermarket addon?

Can you get a couple of pics? Could be an inter-cooler.

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