Overheating While Towing in Mountains

[silver billet]

We have an external cooler. It's up front with the AC condenser. https://www.mymoparparts.com/oem-parts/mopar-condenser-and-trans-cooler-cooler-68312697ac

That's good to know. Somewhere along the line I picked up the idea that it just used the main cooling system.

 

[H3DX]

Thanks for the responses. I'll definitely do 5-20 full synthetic before my next trip over the divide (Aug 12). It goes into service next week. I checked fluid levels and they are fine. Haven't checked to see if both fans are turning (but last time dealer said fans were working). No leaks. Everything is new (bought May 2021). What else in cooling system could be bad? Waterpump?
Oil cooler? Will let you know what happens with service, and the next hill-climb.

Near top of Vail pass. Hi Temp Warning is on. Just before going into crisis mode (AC off, Heater to the max, 40mph).

 

[silver billet]

That doesn't look like a 5th gen truck to me. Do you have a classic?

 

[IvoryHemi]

Agreed^^ that’s a DS not DT

 

[834k3r]

Here's a thread from this forum on the topic.

Oil Temp while Towing

Hey Everybody. I'm new here and have been searching around for answers to my question but haven't found what I am looking for yet. I have a 2021 Ram 1500 5.7L, crew cab 4x4, 6'4", 3.92 axle, ORP, all stock and love the truck so far. This weekend we towed our travel trailer, GVWR 5500lbs up to...

5thgenrams.com

 

[myles]

Thanks for the responses. I'll definitely do 5-20 full synthetic before my next trip over the divide (Aug 12). It goes into service next week. I checked fluid levels and they are fine. Haven't checked to see if both fans are turning (but last time dealer said fans were working). No leaks. Everything is new (bought May 2021). What else in cooling system could be bad? Waterpump?
Oil cooler? Will let you know what happens with service, and the next hill-climb.

Near top of Vail pass. Hi Temp Warning is on. Just before going into crisis mode (AC off, Heater to the max, 40mph).
View attachment 100659

holy crap 275...., you might have burnt your engine oil, but definitely start with going full synthetic.
3500lb trailer and 82 outside temp isn't that crazy... might be something else going on...
I know gas motors aren't the best for towing up hills but it still shouldn't be this bad.

 

[Scram1500]

Since this is a 4th Gen you have a mechanical fan that uses a viscous coupling. It's possible that it's not fully engaged at temp

 

[H3DX]

The truck is a 2021 Ram 1500 classic Warlock. 5th gen, yes?

Would not the Oil Temperature Warning light come on if close to burning oil up? Anyone know
at what temp the Oil Temperature Warning comes on at? And tranny temp warning?

Thanks.

 

[GKIII]

Trans temps look fine here, it's the engine temp that's the problem. IIRC the truck also has an oil to water oil heater/cooler block,

Here's a thread from this forum on the topic.

Oil Temp while Towing

Hey Everybody. I'm new here and have been searching around for answers to my question but haven't found what I am looking for yet. I have a 2021 Ram 1500 5.7L, crew cab 4x4, 6'4", 3.92 axle, ORP, all stock and love the truck so far. This weekend we towed our travel trailer, GVWR 5500lbs up to...

5thgenrams.com

I would say this post is

The truck is a 2021 Ram 1500 classic Warlock. 5th gen, yes?

Would not the Oil Temperature Warning light come on if close to burning oil up? Anyone know
at what temp the Oil Temperature Warning comes on at? And tranny temp warning?

Thanks.

No, that is a 4th gen truck.

Your oil is likely fine, but if it sees conditions like that regularly it's worth going to a high quality full synthetic so it doesn't break down as quickly. FWIW Rotella makes a full synthetic 5w-20 they market specifically to gas trucks used for severe conditions like this.

 

[silver billet]

Yep, your transmission is staying cool all things considered, wouldn't worry about that.

As GKIII said, the 2019+ "classic" or "warlock" is the 4th gen, it's the previous generation truck. Still a great truck and only reason I asked is because there are heating/cooling changes between 4th and 5th gen rams that might make a difference, as scram pointed out your fan is still mechanical whereas ours is all electric. There are transmission cooling changes as well.

 

[H3DX]

Thanks for the clarification. 4'th it is. I looked inside and there appears to be two fans after the engine radiator. The upstream fan looks to be electric and the downstream fan (closest to the engine) appears mechanical. Next time it gets hot, I'll stop and look to be sure both are going ( I presume that would be best).

 

[HoosierTrooper]

I'm not looking to get into an oil weight argument, just throwing a different perspective out there. I can't speak for FCA/Stellantis on this specific motor but I do know for a fact that engine tolerances are revised fairly frequently. It would not surprise me in the least if the tol stack for the early 2000s 5.7 was much looser than it is now. The tighter tolerances require those thinner oils, otherwise there's a lot of unnecessary viscous shear going on with the heavier lubricants.

OP use this information as you will.

I personally think there's an issue with your cooling system. You should not be throwing high motor temp alarms with such a small load.

You have referred to the engine tolerances numerous times when you should be referring to the engines clearances. Different words, different meanings and they are not interchangeable. Clearance is the space between moving parts, such as in a bearing, and tolerance is the amount of variance allowed in the clearance dimensions. Also, the proper term for an oils viscosity classification is grade, not weight, as per the SAE.

 

[silver billet]

Others might disagree, but if I were you I'd change out that oil to a high quality full synthetic tomorrow (or asap), before your next trip. Even if it's not redline which is my goto at the moment, something good. For a start your current oil is probably on the way out anyway (anything above 250 is bad news for standard oil), and this would be a great test to see if a different/better oil helps mitigate this kind of problem, it's great real world testing with no marketing spin or agenda being pushed by somebody. I'd prefer a 5w-30 but would understand if you don't want to go that far.

In fact, if you wanted to run this test, i'd be happy to paypal you $50 to put towards it? I'd just need your forum username printed on a paper next to the dealer receipt and include a screenshot of the temps of your next trip on that oil as some sort of proof I guess. Honestly, this type of feedback would be invaluable to me and I'm sure to many other forum members.

 

[silver billet]

You have referred to the engine tolerances numerous times when you should be referring to the engines clearances. Different words, different meanings and they are not interchangeable. Clearance is the space between moving parts, such as a bearing, and tolerance is the amount of variance allowed in the clearance dimensions. Also, the proper term for an oils viscosity classification is grade, not weight, as per the SAE.

Well I'm not looking to argue semantics, I'm obviously not a mechanical engineer but this is more a logical argument and not a engineering one. The point of my post was:
- the hemi was originaly designed for 5w-30
- as of a few years ago the manual still said it was perfectly acceptable to use (and we know the hemi wasn't updated since then)
- the same 5.7 was put in the 2500 and the manually recommended 5w-30 for towing at all temperatures
- many forum members have run 5w-30, 0w-30, or even 0w-40 for years without any apparent ill effects
- UOA shows great wear numbers with 5w-30

In short, there's nothing wrong with running 5w-30, though from a warranty perspective you'd best be running the certified oil of course.

Edit: and apologies to Hoosier I thought for some reason you quoted me

 

[HoosierTrooper]

Well I'm not looking to argue semantics, I'm obviously not a mechanical engineer but this is more a logical argument and not a engineering one. The point of my post was:
- the hemi was originaly designed for 5w-30
- as of a few years ago the manual still said it was perfectly acceptable to use (and we know the hemi wasn't updated since then)
- the same 5.7 was put in the 2500 and the manually recommended 5w-30 for towing at all temperatures
- many forum members have run 5w-30, 0w-30, or even 0w-40 for years without any apparent ill effects
- UOA shows great wear numbers with 5w-30

In short, there's nothing wrong with running 5w-30, though from a warranty perspective you'd best be running the certified oil of course.

My comments weren’t directed to you, they were to GKIII, he’s made numerous points in this discussion and others in which he uses inaccurate terminology. I agree with you that 5W-30 is perfectly acceptable in the Hemi, possible warranty issues aside, and have made that point before. The difference in kinetic viscosity between a 20 and 30 grade API licensed oil is only a couple centistokes and the argument that the clearances, not tolerances, are too tight to allow the use of a 30 grade is simply not supported by facts.

 

[GKIII]

You have referred to the engine tolerances numerous times when you should be referring to the engines clearances. Different words, different meanings and they are not interchangeable. Clearance is the space between moving parts, such as in a bearing, and tolerance is the amount of variance allowed in the clearance dimensions. Also, the proper term for an oils viscosity classification is grade, not weight, as per the SAE.

Like I said I am not going to get into an oil argument here as I would just offering a counter perspective, but I will address my use of the word 'tolerance' as I use it. I don't work in the automotive world, but rather aerospace so there's probably a vernacular difference. When I am talking tolerances in this context I am talking about optimized tolerance stacks (or analysis, whichever you prefer), which have a direct effect on the actual real-world clearances in an assembly.

You can tighten or loosen individual component tolerances all you want, if you don't do a proper stack you could easily create an unintentional interference elsewhere. In lubricated assemblies, you must also account for the thickness variation in the lubricant film under various conditions in your tolerance stack.

As I previously noted, I can't speak for the HEMI designers and how often they take a look at their stacks but I do have experience with this topic in regards to air breathing jet propulsion. I've had a customer change an efficiency requirement on a small jet turbine, which among other things required us to change the lubricant used on that particular design. Long story short after a series of turbine shaft failures we had to tighten both size and positional tolerances throughout the whole engine to work with the new lubricant, none of the nominal sizes and positions changed...just the overall tol stack. When the same customer requested the engine be certified with a second (thicker) lubricant for a different application the whole damn thing ran significantly hotter because of the extra resistance we introduced. It was barely within spec (and less efficient), but if it that engine wasn't for a single use application there would be serious longevity concerns with the thicker lubricant.

So if FCA changed to a 5W-20 oil to meet fuel efficiency requirements, those engineers would have looked at the the tolerances in the crankcase, along the crankshaft, the camshaft, and any runout tolerances they spec on those parts (not an all inclusive list, obviously) to make sure that thinner oil doesn't cause any additional wear. If they DIDN'T at least take a look, then I dunno what to say other than the beancounters got involved. In most cases a thinner lubricant is going to require more precision where average clearances are smaller throughout the assembly even if the nominal sizes/positions stay the same.

Also, noted about the weight vs grade terminology. It's a habit at this point hah.

 

[GKIII]

My comments weren’t directed to you, they were to GKIII, he’s made numerous points in this discussion and others in which he uses inaccurate terminology. I agree with you that 5W-30 is perfectly acceptable in the Hemi, possible warranty issues aside, and have made that point before. The difference in kinetic viscosity between a 20 and 30 grade API licensed oil is only a couple centistokes and the argument that the clearances, not tolerances, are too tight to allow the use of a 30 grade is simply not supported by facts.

Any comment I made in reference to using 30 grade oil is in reference to heat generation caused by that thicker oil, which does matter when you're talking about edge cases like this. Could 5w-30 be run in the 5w-20 spec'd HEMIs? I don't doubt it, but I would also bet those that do generate a bit more heat on average. Which...is fine if your cooling system can compensate for that heat.

The crux of my argument specific to this thread is yea sure 5w-30 works. Lots of of people do it with zero issues. But if you're having temperature issues towing up a mountain, I don't think going to a thicker oil is what you want to do in these motors. That extra viscosity both generates slightly more heat and thicker oils do not transfer heat as efficiently as a thinner one. Again, we are talking about edge cases.

 

[silver billet]

I do appreciate your comments, GKIII. But one other thing to keep in mind, is that 5w-30 at 260+ degrees is actually thinner than 5w-20 at "normal" temps. So I think that's partly where the recommendation for thicker oil comes from as well.

When my truck isn't working but just hot, it stays at 106 C which is about 222 F. The hottest I've seen it is 230 F pulling my trailer. So as far as I can see there doesn't appear to be any issue keeping it cool with a very thick 30 weight (RL 5w-30 is closer to most oils 5w-40 in thickness).

 

[GKIII]

I do appreciate your comments, GKIII. But one other thing to keep in mind, is that 5w-30 at 260+ degrees is actually thinner than 5w-20 at "normal" temps. So I think that's partly where the recommendation for thicker oil comes from as well.

When my truck isn't working but just hot, it stays at 106 C which is about 222 F. The hottest I've seen it is 230 F pulling my trailer. So as far as I can see there doesn't appear to be any issue keeping it cool with a very thick 30 weight (RL 5w-30 is closer to most oils 5w-40 in thickness).

As @HoosierTrooper has noted, it's not that much thicker so we may be talking less than 1 degree under normal loads. IIRC the efficiency gain going from 30 to 20 grade oils is less than 1%. However, my preferred solution is to keep it all from getting that hot in the first place and every little bit helps lol. If I remember correctly the oil "cooler" (er...heater) in our trucks is a oil to water heat exchanger. That extra heat is getting dumped into the main radiator core, which isn't helping things. (Feel free to correct me if I'm wrong there).

I still think the main issue is the primary cooling system. Fixing that will fix the hot oil issue too if I'm correct about the oil heat exchanger.

Who knows, if the fans are working maybe the system wasn't completely bled properly? Bad water pump?

 

[JF19Longhorn]

What is the frontal area of your trailer? Basically I'm asking if it's a brick in the wind or has some streamlining. I know somewhere in the depths of the towing guides they take into account frontal area of the towed vehicle can't be greater than X sqft @ XXXX weight. Maybe that's your problem and it's amplified by speed and incline?

If that isn't the issue I'd be looking at a possible blockage in the Radiator, factory defect maybe. Doesn't have enough blockage to affect anything unloaded, but when you put her to work, it cannot keep up. Though how to get the stooges at the dealership to check for that is anyone's guess.