Florida to Wyoming in my Class A

[Lurker52]

I just made a trip from Florida to Wyoming in my 2001 Monaco Knight with a Cummins ISB 5.9 with 300 HP and an Allison 3000 transmission. I also am towing my 2011 Tuscan on a tow dolly. The trip was about 2300 miles. Traveling through FL. AL. MS. and MO. was pretty uneventful. I started across Nebraska from Omaha to North Platte and the rig ran fine.

After leaving North Platte west on I-80 toward Cheyenne the road started heading up hill. No big grades just a constant up hill run for like 200 miles and about 3000’ elevation gain. As the day went on and got hotter to over 90 degrees, I started running hot. Up around 200 degrees. I was getting nervous and pulled over to cool the rig down. I even called Cummins who said I would be fine as long as no warning bussers went off. That didn’t make me feel better.

I got to Cheyenne and was there for a coupe of days so I did some reading on this and other RV sites and learned that A LOT of people run at 200 or more. I still was hoping to get my temp down. My rig runs at about 185 on flat land. I even stopped and talked to a local diesel shop. Between my research and the diesel mechanic it sounded like clogged radiator fins. When I got back to my RV I crawled around under it found there was oil build up on the radiator. So after about 2 hours of hosing it down I got it pretty clean. I don’t think the 5 star resort I was at will ever notice the oil on the dirt patch they called a sight. ??

While waiting for DW to get a hair cut I noticed an RV just like mine in the Walmart parking lot. I knocked on the door and the owner was very nice and invited me in. I asked about his rig and how it preformed. He had a 315 HP motor. He said both are RVs are under powered. I think I have to agree.

The owner said he was leaving Cheyenne at night to make the grade near Laramie without overheating. He was pulling a Tahoe. I was not happy to hear this but I was not leaving at night.

I left Cheyenne about 9:00 A.M. for Rock springs the grade over to Laramie was no problem. But the other thing I learned and did was to keep my RPM at about 2200 and shift down when needed to keep them there. The rest of the day was fine. One looong grade before Rock springs the rig did get close to 200 but cooled down at the top.

My last day from Rock springs to Star Valley went fine except for a 2-3 mile 8% grade before Afton. The rig actually did OK. The temp did get up to about 200 and I was in 3rd gear before cresting the top.

I am now in Star Valley for a month before heading back to Florida. All down hill (haha) This was the first big trip with this RV. If my return trip is no more eventful than this one I will be happy.

So, a couple of things I’ve learned are, make sure the radiator is clean keep the RPM up to 22-2300 on long grades and use the shifter to keep them up and not wait for the trans to hunt for the gears and loose power in doing so.

I am interested in any advice you all may have or anything I can do to improve the ride on the way home.

Thanks, as always

[bigred1cav]

We had the same overheating problem on the same highway in 2018. I learned to not use cruise control and keep it at no more than 2500 RPM.

Lurker52 wrote:
I just made a trip from Florida to Wyoming in my 2001 Monaco Knight with a Cummins ISB 5.9 with 300 HP and an Allison 3000 transmission. I also am towing my 2011 Tuscan on a tow dolly. The trip was about 2300 miles. Traveling through FL. AL. MS. and MO. was pretty uneventful. I started across Nebraska from Omaha to North Platte and the rig ran fine.

After leaving North Platte west on I-80 toward Cheyenne the road started heading up hill. No big grades just a constant up hill run for like 200 miles and about 3000’ elevation gain. As the day went on and got hotter to over 90 degrees, I started running hot. Up around 200 degrees. I was getting nervous and pulled over to cool the rig down. I even called Cummins who said I would be fine as long as no warning bussers went off. That didn’t make me feel better.

I got to Cheyenne and was there for a coupe of days so I did some reading on this and other RV sites and learned that A LOT of people run at 200 or more. I still was hoping to get my temp down. My rig runs at about 185 on flat land. I even stopped and talked to a local diesel shop. Between my research and the diesel mechanic it sounded like clogged radiator fins. When I got back to my RV I crawled around under it found there was oil build up on the radiator. So after about 2 hours of hosing it down I got it pretty clean. I don’t think the 5 star resort I was at will ever notice the oil on the dirt patch they called a sight. ??

While waiting for DW to get a hair cut I noticed an RV just like mine in the Walmart parking lot. I knocked on the door and the owner was very nice and invited me in. I asked about his rig and how it preformed. He had a 315 HP motor. He said both are RVs are under powered. I think I have to agree.

The owner said he was leaving Cheyenne at night to make the grade near Laramie without overheating. He was pulling a Tahoe. I was not happy to hear this but I was not leaving at night.

I left Cheyenne about 9:00 A.M. for Rock springs the grade over to Laramie was no problem. But the other thing I learned and did was to keep my RPM at about 2200 and shift down when needed to keep them there. The rest of the day was fine. One looong grade before Rock springs the rig did get close to 200 but cooled down at the top.

My last day from Rock springs to Star Valley went fine except for a 2-3 mile 8% grade before Afton. The rig actually did OK. The temp did get up to about 200 and I was in 3rd gear before cresting the top.

I am now in Star Valley for a month before heading back to Florida. All down hill (haha) This was the first big trip with this RV. If my return trip is no more eventful than this one I will be happy.

So, a couple of things I’ve learned are, make sure the radiator is clean keep the RPM up to 22-2300 on long grades and use the shifter to keep them up and not wait for the trans to hunt for the gears and loose power in doing so.

I am interested in any advice you all may have or anything I can do to improve the ride on the way home.

Thanks, as always

[atsrmf]

200 degrees is not hot for a gas or diesel engine, in my opinion. Above that I would slow down for a while, assuming normal driving conditions. Towing is always going to add a few degrees, too.

[rgatijnet1]

When I flush out my radiator the most difficult thing is to get the water source on the back side of the radiator. Flushing from the backside will move the debris out rather than possibly driving it deeper in the fins if you flush from the air intake side. I have an AC condenser and an electric fan and I can take them loose to clean out debris that got between them. I use Simple Green EXTREME, not plain Simple Green, which will not cause corrosion if any of the cleaning fluid is left behind.

[jplante4]

I use foaming A/C coil cleaner in the Sahara twice a year. There's an additional issue with this rig because the intercooler is sandwiched against the rad so stuff builds up in between. CAT motors also have a slobber tube that dumps the crankcase vent under the motor adding to the problem. I've done the slobber tube re-route and it seemed to help with the amount of muck.

My thermostat is 195° so 200 is ok. On most new electronic engines, the ECM won't allow the motor to self destruct. Downshifting circulates the water faster and runs the fan higher.

[ppine]

When towing heat is the enemy. It is important to use your tach and stay in the power band. Clean radiator works a lot better. How about the inside?

Check your thermostat. You might be able to find one with a slightly lower opening temp.

Back in the 1960s we drove old cars like '57 Chevys cross country. They had no AC and tended to overheat, so we always drove across deserts at night.

[westernrvparkow]

JRscooby wrote:

westernrvparkowner wrote:
Should have left your contact information at that site where you hosed off the oil. I am sure the next occupants will want to send you a thank you note when they unknowingly track that oil into their rig. There are car and truck washes for a reason. But the self absorbed seldom see any reason beyond their own selfish ones.

Thank you. I'm not educated enough to give my thoughts on that, and stay in the "be nice" rule...

It is an issue I have become acutely aware of.

[JRscooby]

westernrvparkowner wrote:
Should have left your contact information at that site where you hosed off the oil. I am sure the next occupants will want to send you a thank you note when they unknowingly track that oil into their rig. There are car and truck washes for a reason. But the self absorbed seldom see any reason beyond their own selfish ones.

Thank you. I'm not educated enough to give my thoughts on that, and stay in the "be nice" rule...

[westernrvparkow]

Should have left your contact information at that site where you hosed off the oil. I am sure the next occupants will want to send you a thank you note when they unknowingly track that oil into their rig. There are car and truck washes for a reason. But the self absorbed seldom see any reason beyond their own selfish ones.

[JRscooby]

Most don't act like they understand 2 facts I learned before I turned 30. 1)The harder a engine is working, the more heat it has to get rid of. 2) The faster you want to go, the harder your engine needs to work to meet your expectations.
The first thing to do when engine temp starts to get outside your comfort range slow down![/]

[Ivylog]

X2 on above post although 200 is not too hot...230 is.

[Tyler0215]

You did the right thing. Revs up, and a clean radiator.