Keeping coolant and transmission temps under control when towing in the summer heat

[ls1frc]

The trip home was a different story. Much hotter weather, still pulling the camper. My ambient temperature sensor has been relocated to a better place and always reads between 2-3º of ambient air temp as reported by my Apple Watch . Anyway, ambient temp according to the truck (full sun on the highway) was high 90s for most of the trip, with a few peaks into 100-101ºF. We were on I-64 westbound between Norfolk and Richmond and the transmission temp hovered around 207ºF with the coolant temp staying around 210ºF. We hit some stop and go traffic and the transmission would peak around 215ºF once we got going and I saw the coolant hit 230ºF a couple of times on some longer grades at 65-70 mph. We pulled off the highway to get to the house and the transmission temp peaked at 232ºF with all of the traffic lights, while the engine coolant dropped to around 200ºF. By the time we got to the house the transmission had settled to around 225ºF

Net/Net, the transmission stays cool on the highway until it has to do a lot of shifting in traffic (to be expected), and there is a time lag of 5 minutes between pulling off the highway, and maximum transmission temp in traffic before it starts to come down again. The coolant runs a little warm on the highway until I get off and it cools down quickly. I'm not getting the cooling from the Derale I was hoping for. It's less effective than the Tru-Cool was.

Next steps: 1/ Fix the baffles beside the radiator permanently with some coroplast. When I got home I noticed my temporary repair had failed, so that should help the coolant temps on the highway. 2/ Fab up some deflectors from sheet aluminum to increase ram airflow to the Derale, since it's mounted behind the license plate. I also noticed that the Derale fan started making some noise, so I will investigate that as well.

The weekend after next, I'll be running the same road that saw my transmission temp hit 265ºF before I rerouted the transmission cooler lines through the radiator. We'll see if plumbing the radiator cooler back into the system really does anything to shave off those higher temp spikes.

Gotta get this thing 100% dialed in before mid August when we hit the road for Yellowstone and the Tetons.

Good info.

I'd love to take my family on one of these trips. Can you link me to some good resources for newbs? Good spots to go etc?

 

[Geotrash]

Good info.

I'd love to take my family on one of these trips. Can you link me to some good resources for newbs? Good spots to go etc?

Happy to. Are you interested in links to travel trailer camping resources or just resources for great campgrounds or places to visit in the area?

 

[gooffeyguy]

I noticed while scrolling through the parameters on my tuner that the cooling fans must be variable speed.

The tuner had different temps and each had a fan power percentage that could be set

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[Geotrash]

I noticed while scrolling through the parameters on my tuner that the cooling fans must be variable speed.

The tuner had different temps and each had a fan power percentage that could be set

Sent from my SM-G930V using Tapatalk

Y’all are gonna get me to invest in an HP Tuner for these things and figure out how to use it right, aren’t you.

Is HP the one you use?


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[gooffeyguy]

Y’all are gonna get me to invest in an HP Tuner for these things and figure out how to use it right, aren’t you.

Is HP the one you use?


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No, my Diablo Intune I3

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[Geotrash]

No, my Diablo Intune I3

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Right. I remember that now.


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[03_GMC]

I noticed while scrolling through the parameters on my tuner that the cooling fans must be variable speed.

The tuner had different temps and each had a fan power percentage that could be set

Sent from my SM-G930V using Tapatalk

I’ve been saying this for awhile now. I am tuned and had my fans changed to be more aggressive at lower temps. I am really curious to see how it does this trip.


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[ls1frc]

Happy to. Are you interested in links to travel trailer camping resources or just resources for great campgrounds or places to visit in the area?

All of the above! I am in PA, I am sure there are tons of nice areas around here that I don't even know about.

 

[Geotrash]

All of the above! I am in PA, I am sure there are tons of nice areas around here that I don't even know about.

I grew up in PA. One of my favorite places is an area near Clarion, called Cook Forest State Park.

If it's helpful, here is a list of links I use all the time for planning our camping adventures. And here also are a couple of links to camping forums that are chock full of great insights for people new to travel trailers/RVs, plus some of our favorite local spots.

For people who like to camp for free/low cost/off grid:
https://www.hipcamp.com/en-US

For people who like wine. Wineries will often make space available for campers through the Harvest Hosts program:
https://harvesthosts.com

Fabulous resource for planning cross country camping trips:
https://www.rvtripwizard.com

RV Life is a great resource:
https://rvlife.com

Great forum for owners of Forest River products, but there is a ton of other discussion threads an all kinds of stuff:
https://www.forestriverforums.com/forums/

And last but not least, the RV Forum:
https://www.rvforum.net

Great link to some RV channels for people new to RVs:
https://rvlife.com/best-youtube-channels-for-rvers/

I really enjoy this couple's videos. They're adorable:
https://www.youtube.com/channel/UChOqiLlC-SZdoIQ68tsTgBw

Some really great destinations in our area that are awesome for kids:
https://www.cherrystone.com/virginia-campgrounds/
https://www.dcr.virginia.gov/state-parks/first-landing (our daughter's absolute favorite campground. It's right on Virginia Beach)
https://koa.com/campgrounds/williamsburg/

 

[Foggy]

Thru my Diablosport, I have noticed that the fans don't really come on
the low setting until about 44% fan command..
The fans aren't really "variable speed", just Low or High Speed

I have to "get into" my HP Tuners and learn it so I can turn the
Fan Command % numbers UP at highway speeds.
They don't really go over 25% even at 210* at speed.. At low speeds,
they start on low speed at 202* and will go up to 90% with AC on
or if temp goes over 212*.
Kinda dumb system IMO.. Why not just OFF/LOW/HIGH like many
of my other "fan command states"

 

[Geotrash]

Thru my Diablosport, I have noticed that the fans don't really come on
the low setting until about 44% fan command..
The fans aren't really "variable speed", just Low or High Speed

I have to "get into" my HP Tuners and learn it so I can turn the
Fan Command % numbers UP at highway speeds.
They don't really go over 25% even at 210* at speed.. At low speeds,
they start on low speed at 202* and will go up to 90% with AC on
or if temp goes over 212*.
Kinda dumb system IMO.. Why not just OFF/LOW/HIGH like many
of my other "fan command states"

Very helpful observations - thanks for sharing them. I'm wondering if maybe they set them that way to prolong the life of the fan motors, or if maybe other fan speeds become available under different combinations of factors.

I've noticed that while my coolant temp will get up as high as 230ºF on a hot day towing on the interstate, that it stays cool (below 215ºF) when climbing a long 7+% grade, even though I'm only doing maybe 35 by the time I reach the top. This, while my transmission temps climb through the roof. Makes me wonder if the fan speed will increase as vehicle speed decreases to compensate for loss of ram air.

 

[Geotrash]

Relocated the license plate last night and drilled out the holes for better ram air to the Derale. I used 4" long machine screws with washers and locking nuts, and cut some 3.5" long pieces of pex pipe to serve as standoffs to keep the plate rigid. I sometimes use an automatic carwash, and don't want the spinning brushes pulling the plate off if I can help it.

 

[gooffeyguy]

Relocated the license plate last night and drilled out the holes for better ram air to the Derale. I used 4" long machine screws with washers and locking nuts, and cut some 3.5" long pieces of pex pipe to serve as standoffs to keep the plate rigid. I sometimes use an automatic carwash, and don't want the spinning brushes pulling the plate off if I can help it.

View attachment 281422
View attachment 281424

Shit, I'm surprised you didn't do what many people do around here that don't want the look of a front plate or don't want to drill holes in their new aftermarket bumper for it. Lay it on the passenger side dash up in the windshield

 

[HD_LS]

Very helpful observations - thanks for sharing them. I'm wondering if maybe they set them that way to prolong the life of the fan motors, or if maybe other fan speeds become available under different combinations of factors.

I've noticed that while my coolant temp will get up as high as 230ºF on a hot day towing on the interstate, that it stays cool (below 215ºF) when climbing a long 7+% grade, even though I'm only doing maybe 35 by the time I reach the top. This, while my transmission temps climb through the roof. Makes me wonder if the fan speed will increase as vehicle speed decreases to compensate for loss of ram air.

Do you have the AC off on the uphill climbs?

 

[Geotrash]

Do you have the AC off on the uphill climbs?

No, and I'm trying to avoid having to do that unless there is literally no other option. I'm optimistic that with this final mod that I'll be able to keep the temps under control for good, for any of the towing we have planned this year and will plan in the years ahead.

 

[exp500]

For Ya'all that are looking for that extra edge especially towing, this has been good for me and inexpensive.

WaterWetter®

Unique agent for cooling systems that doubles the wetting ability of water

www.redlineoil.com

 

[03_GMC]

Ok for some reason Tapatalk won’t log me in. So how about a first day report?

We went from East of Dallas to North Denver in a day. 14 hrs with stops. Saw a best of 11.5 MPGs. This little trailer is all steel. Frame, panels and inside framing as well. It’s a fairly stout and heavy little guy.

For most of the day trans temps averaged between 176-185. On a few two lane road vehicle passes the temp would climb to 205 and then come back down afterwards. When I arrived in Limon on I70 I stopped to fill up and the temp creeped up to 210. I figured I should probably see if the thermostat was working. I climbed under the Denali and sure enough it wasn’t. Then all of a sudden it came on for about 10 seconds and shut off again. So I grabbed my tools and made a straight connection to the fans positive wire. After that the temp never rose above 185. My coolant temp never budged the entire day so having the tune reprogram the fans is a huge benefit.

Today we pick up the rental camper. A Grand Design Imagine 2400BH. I’ll report back tonight with how our trip from Denver to Rock Springs Wyoming went!

 

[Fless]

FYI Tapatalk is no longer supported in the new version of the forum. See the "What Happened" thread.

 

[Geotrash]

Ok for some reason Tapatalk won’t log me in. So how about a first day report?

We went from East of Dallas to North Denver in a day. 14 hrs with stops. Saw a best of 11.5 MPGs. This little trailer is all steel. Frame, panels and inside framing as well. It’s a fairly stout and heavy little guy.

For most of the day trans temps averaged between 176-185. On a few two lane road vehicle passes the temp would climb to 205 and then come back down afterwards. When I arrived in Limon on I70 I stopped to fill up and the temp creeped up to 210. I figured I should probably see if the thermostat was working. I climbed under the Denali and sure enough it wasn’t. Then all of a sudden it came on for about 10 seconds and shut off again. So I grabbed my tools and made a straight connection to the fans positive wire. After that the temp never rose above 185. My coolant temp never budged the entire day so having the tune reprogram the fans is a huge benefit.

Today we pick up the rental camper. A Grand Design Imagine 2400BH. I’ll report back tonight with how our trip from Denver to Rock Springs Wyoming went!

Fabulous! Thanks for the update + data, and safe travels!

 

[Fless]

Also give us an idea which route you take from North Denver -- I-25 to Cheyenne, 287 to Laramie, or ?