5.7 overheating when towing in mountains

[ExpressRules]

I'd normally think thermostat not fully opening, but since you had the water pump replaced i imagine the garage changed it while doing that. On my 14 had overheating a little less then 2 years ago and first thought I had was thermostat was not fully opening and being such an easy fix popped a new one in. Didn't help and thing i finally realized was the fan had a lot of play because the fan clutch was shot and also found that the water pump was seeping.

I was too quick to blame the thermostat without taking time to investigate the entire system.

 

[Curmudgeon]

Real easy home diy test for any automotive thermostat: Fill at pot with water (NOT your wife's best pot!!) and turn on the heat while watching the water temp on a kitchen/candy/meat thermometer and also watching to see when the thermostat begins to open, and fully opens.

Chances are really pretty good you'll see a problem if one exists. Good idea to do this right before installing that new one to make sure it works as expected.
Nothing to make us crazy like installing a new part only to find out the hard way that it is defective.

*I learned this cool trick here.

 

[ramffml]

Verify if your truck has the active grill shutters. If it does I would be looking closely at those to make sure they are opening. Generally if overheating is occurring at highway speeds I look for airflow blockages to the radiator (i.e. like the radiator with clogged with mud/dirt....and the AGS could cause the same issue). Generally don't suspect cooling fans at highway speeds. That is because you are getting a lot of airflow through the radiator simply running at highway speeds, and the fans are mainly to push air through the radiator when stopped or lower speeds.
Putting a lower temp thermostat is not going to fix the problem at all. A 203 F thermostat flows the exact same amount of coolant when open as the 160 F thermostat. It doesn't change the cooling capability of the system, it just opens sooner. If the cooling system allows the engine to get hot with a 203 F thermostat, how in the world is it going to maintain a lower temp? If the engine is getting up to 250 F with a 203 F thermostat........it's still going to get up to 250 F with a lower temp thermostat. Again, there is zero difference in the capability of the cooling system if you have a fully open 203 F thermostat as compared to a fully open 160 F thermostat.

It's a little more subtle than what you're describing. As one who has is using a 180 tstat for a few years now I can safely say my temps are far lower now while towing. The reason is because the coolant temp is cooler, coolant is always sitting around 188 to 195 instead of well past that. That means the oil temps are going to be lower too.

Now when you run up against a grade, your starting temperatures are also lower, giving you a longer runway before you hit 250.

I do agree that eventually you WILL hit the same temps you saw before, but it will take much longer to get there, and your truck then cools down to a lower value again after it.

So yeah, definitely put in a 180 and it will give you more runway. But if you find a longer hill, you might reach those same temps again, it will just take you longer to get there. In my case, it's been enough, I've never hit 250 again. Usually it peeks around 230 to 235 and then cools down to 225. I now tow on the straights at the same temps (225ish) that my truck used to run unladen. In the quite cold Southern ON winters reaching -10F, I've never run out of heat either, so I keep the 180 in year round. One of the best changes I made.

 

[Hemi395]

I test all my thermostats in a pot of boiling water. One thing Ive noticed across the board is that any lower temp tstat, no matter the brand, opens more than the Mopar 203 thermostat at 212⁰

So in theory, a lower temp tstat might yield a bit more overall cooling capacity just due to slightly more coolant flow

 

[Bigskyroadglide]

Op on a 21 warlock you should not have active grill shutters. In addition you should have a tow haul button so you don't need to shift down to seven or six gear. Push the button, it's what it's there for, towing!

Then put your air conditioner on automatic, it's there in the center, push that button.

Then make certain your running 89 or greater fuel octane. Then let the hemi eat.

Rpms should/probably will be about 3k to 5k, depending on gear ratio the engine will whine but its doing the work as designed. With tow haul the transmission will lock in 6the gear as the highest gear.

If it gets hot, then suggest it potentially has an air bubble from the coolant change which you need to get out.

Last thing I'd recommend good 5w30 synthetic oil. And a decent filter like a royal purple 20 820.

I've pulled that interstate several times through to the Eisenhower tunnel in my 2016 5.7 hemi Laramie with ags and a 7x14 trailer with two 900 lb Harleys inside, I never have seen a temp over 230. Truck had 90k miles on when sold.

 

[Hambodian]

I've got a '19 Warlock with 80K miles towing a 20' travel trailer over the mountains. Been doing good with no overheating so far. I don't know if octane rating makes a difference, but I only use 89. Maybe check the air filter and exhaust for any restrictions too?

 

[Wild one]

Take enough tools with you to remove the grill completely if you run into overheating issues again. Pulling the grill even with the honeycomb inserts will let alot more air flow through the "whole" rad,and might help get you home.It's a stop gap fix but i've done it a few times just to get something home.You could also gut your old thermostat and turn it into a restrictor plate,as it'll allow more coolant circulation then a fully open thermostat does,but not enough that the coolants moving to fast through the engine to remove the heat from the engine.Those are only things i'd do to get home though,if i'm stuck on the side of the road. Also wouldn't hurt to take a jug or 2 of water or pre-mixed coolant in case you need to do a little work to it on the side of the road.The worst thing is having to work on it,on the side of the road,and not having any water or premixed coolant to pour back into it.

 

[Hemi395]

Take enough tools with you to remove the grill completely if you run into overheating issues again. Pulling the grill even with the honeycomb inserts will let alot more air flow through the "whole" rad,and might help get you home.It's a stop gap fix but i've done it a few times just to get something home.You could also gut your old thermostat and turn it into a restrictor plate,as it'll allow more coolant circulation then a fully open thermostat does,but not enough that the coolants moving to fast through the engine to remove the heat from the engine.Those are only things i'd do to get home though,if i'm stuck on the side of the road. Also wouldn't hurt to take a jug or 2 of water or pre-mixed coolant in case you need to do a little work to it on the side of the road.The worst thing is having to work on it,on the side of the road,and not having any water or premixed coolant to pour back into it.

^^^This!!

 

[Hemi395]

This is taken out the air intake cutout on thw grill. The difference in flow between these 2 grills is clear.

The Bighorn/Sport grill does have failry large openings on the bottom (you have to look up from the ground to see them), but it deflects the air up and it must slow flow down considerably.

 

[Burla]

Take enough tools with you to remove the grill completely if you run into overheating issues again. Pulling the grill even with the honeycomb inserts will let alot more air flow through the "whole" rad,and might help get you home.It's a stop gap fix but i've done it a few times just to get something home.You could also gut your old thermostat and turn it into a restrictor plate,as it'll allow more coolant circulation then a fully open thermostat does,but not enough that the coolants moving to fast through the engine to remove the heat from the engine.Those are only things i'd do to get home though,if i'm stuck on the side of the road. Also wouldn't hurt to take a jug or 2 of water or pre-mixed coolant in case you need to do a little work to it on the side of the road.The worst thing is having to work on it,on the side of the road,and not having any water or premixed coolant to pour back into it.

Wait til he is on the road, yeah thanks alot, lol. Maybe he'll drive near a harbor freight, cheap enough, at least here in the states.

Hex Monkey wrench, will take care of most nuts and give torque. Every truck needs one. Unless I am wrong, I think all sizes have the same opening, which means go small 9 inch and have a steel bar if you need some extra torque. And big crescent as well, but you will grab this one more.

 

[Wild one]

Wait til he is on the road, yeah thanks alot, lol. Maybe he'll drive near a harbor freight, cheap enough, at least here in the states.

Hex Monkey wrench, will take care of most nuts and give torque. Every truck needs one. Unless I am wrong, I think all sizes have the same opening, which means go small 9 inch and have a steel bar if you need some extra torque. And big crescent as well, but you will grab this one more.

View attachment 572413

That's a bit big and rough for grill removal Mike . If he's going on a 2500 mile trip,and he's already had over heating issues,he should hopefully of took a toolbox full of some tools ,and a couple jugs of water or pre-mixed coolant with him,i know i would,as that's just common sense

 

[Burla]

Grill would be amazing, but if his reporting is accurate it wont solve the quick jumping of temp.

 

[62Blazer]

It's a little more subtle than what you're describing. As one who has is using a 180 tstat for a few years now I can safely say my temps are far lower now while towing. The reason is because the coolant temp is cooler, coolant is always sitting around 188 to 195 instead of well past that. That means the oil temps are going to be lower too.

Now when you run up against a grade, your starting temperatures are also lower, giving you a longer runway before you hit 250.

I do agree that eventually you WILL hit the same temps you saw before, but it will take much longer to get there, and your truck then cools down to a lower value again after it.

So yeah, definitely put in a 180 and it will give you more runway. But if you find a longer hill, you might reach those same temps again, it will just take you longer to get there. In my case, it's been enough, I've never hit 250 again. Usually it peeks around 230 to 235 and then cools down to 225. I now tow on the straights at the same temps (225ish) that my truck used to run unladen. In the quite cold Southern ON winters reaching -10F, I've never run out of heat either, so I keep the 180 in year round. One of the best changes I made.

Understand where you are coming from and agree with you for the most part. I think the main difference is you are talking about putting a lower temp thermostat on a cooling system that is working correctly and has the ability to keep the engine at a reasonable temp, at least the majority of the time. My perspective on the OP is that there is something wrong with the cooling system that is allowing it to overheat, especially considering the conditions are not extreme by any means. The factory cooling system should be sufficient to keep the engine from overheating (or giving a warning) under pretty extreme conditions. You can reference the industry standard J2807 Towing Test that manufacturers use and it states the same. I also use to work in the automotive testing field back before the J2807 came out and can tell you that manufacturers designed and tested the trucks so they stayed cool under maximum towing conditions (towing max weight up long grades).
So yes, putting a lower temp thermostat in a properly working vehicle will do what you say, but a lower temp thermostat is not a very good band-aid for a cooling system that has an issue and allowing the truck to overheat.

 

[Wild one]

Grill would be amazing, but if his reporting is accurate it wont solve the quick jumping of temp.

Pulling the grill does make a noticable differance,it and a 180 t-stat will give him alot more lee way before he's into the danger zone. Personally i think he might have other issues,but those 2 mods will give him some working room to make the trip if he's still got over heating issues while towing

 

[ramffml]

Understand where you are coming from and agree with you for the most part. I think the main difference is you are talking about putting a lower temp thermostat on a cooling system that is working correctly and has the ability to keep the engine at a reasonable temp, at least the majority of the time. My perspective on the OP is that there is something wrong with the cooling system that is allowing it to overheat, especially considering the conditions are not extreme by any means. The factory cooling system should be sufficient to keep the engine from overheating (or giving a warning) under pretty extreme conditions. You can reference the industry standard J2807 Towing Test that manufacturers use and it states the same. I also use to work in the automotive testing field back before the J2807 came out and can tell you that manufacturers designed and tested the trucks so they stayed cool under maximum towing conditions (towing max weight up long grades).
So yes, putting a lower temp thermostat in a properly working vehicle will do what you say, but a lower temp thermostat is not a very good band-aid for a cooling system that has an issue and allowing the truck to overheat.

I don't know what to say, other than that many people have reported hitting 250F on stock truck while towing? Myself included. So nothing wrong with the truck per se, all working as designed, but the system can't keep up even when working properly.

 

[62Blazer]

I don't know what to say, other than that many people have reported hitting 250F on stock truck while towing? Myself included. So nothing wrong with the truck per se, all working as designed, but the system can't keep up even when working properly.

I guess it comes down to whether or not the overheating is "normal" or not. Just wouldn't expect a newer truck to overheat in these conditions (OP reported 65 degree temperatures which isn't very warm, and only a 4,000 lb. trailer which is less than half...if not only a 1/3...of the rated towing capacity). I know the I-70 Eisenhower Tunnel area is one of the biggest grades around, but still.
I do not have personal experience towing with a 1500 Ram, and have never towed through that area. So not saying anybody is wrong or making anything up....but I have towed trailers for 30+ years and did automotive testing for a long time. Just find it surprising that it is normal for a truck like this in good operating condition to overheat in these conditions.

 

[ramffml]

I guess it comes down to whether or not the overheating is "normal" or not. Just wouldn't expect a newer truck to overheat in these conditions (OP reported 65 degree temperatures which isn't very warm, and only a 4,000 lb. trailer which is less than half...if not only a 1/3...of the rated towing capacity). I know the I-70 Eisenhower Tunnel area is one of the biggest grades around, but still.
I do not have personal experience towing with a 1500 Ram, and have never towed through that area. So not saying anybody is wrong or making anything up....but I have towed trailers for 30+ years and did automotive testing for a long time. Just find it surprising that it is normal for a truck like this in good operating condition to overheat in these conditions.

TFL routinely torture tests trucks and has managed to overheat several of them though I don't remember which trucks off the top of my head. Eisenhower is not the worst test out there, anything long, steep, and slowwill cause it to overheat. Not enough wind through the rad and its game over.

 

[ramffml]

Found one of the videos back, this F150 3.5 EB is pegged pedal to the floor and probably getting derated by the computer, note the oil temp at 251F

Couple seconds later it hits 255 and then a message on the dash about it overheating.

https://youtu.be/J8hZ5bwgd9A?t=449

In a previous test they did, a GMC overheated its transmission.

Here is another test of the Ram hurricane SO, and surprisingly it does better than both by not overheating at all. They did get 19 psi oil pressure but that was just a software calibration issue which TFL has said in a later video that is already corrected.

https://www.youtube.com/watch?v=Ld2fTLqQ9rE

I know for sure my truck (hemi) would have overheated on that test when stock. Possibly now even with my little mods.

 

[Jas34]

The first thing I would have done with your issue is take a good look at the radiator and AC condenser fins and blow them out from the cowl out with compressed air or a garden hose. You won't believe the crap and bugs they sometimes pick up with time, especially if you have cottonwood trees around. That alone could be causing your overheating and it's a real cheap fix to try first.

 

[62Blazer]

Found one of the videos back, this F150 3.5 EB is pegged pedal to the floor and probably getting derated by the computer, note the oil temp at 251F

Couple seconds later it hits 255 and then a message on the dash about it overheating.

https://youtu.be/J8hZ5bwgd9A?t=449

In a previous test they did, a GMC overheated its transmission.

Here is another test of the Ram hurricane SO, and surprisingly it does better than both by not overheating at all. They did get 19 psi oil pressure but that was just a software calibration issue which TFL has said in a later video that is already corrected.

https://www.youtube.com/watch?v=Ld2fTLqQ9rE

I know for sure my truck (hemi) would have overheated on that test when stock. Possibly now even with my little mods.

Just to be clear, I'm not trying to argue or anything. Just making some statements to consider.
The F-150 did give them an overheat message in the above video. The thing to consider when comparing the OP to this video.
- The F-150 is pulling the maximum weight trailer around 10,000, foot to the floor, and only going 18 mph. I didn't see them mention the outside temp but would expect it was hotter outside.
- The OP was only pulling 4,000 lbs. which is less than half, at the most, of the max towing capacity. They did not specify the speed or if they were running foot to the floor. I would suspect if the F-150 was only towing 4,000 lbs., running even twice the speed at 36 mph, and the outside temp was cooler the outcome would have been different.
Again, I don't want to sound like I'm arguing or disagreeing.......just adding in the way I look at it. Mainly there are a lot of different variables going on here that could affect the outcome.