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Hello everyone. It has been questioned if the LLY trucks can tow on hot days up steep hills pulling heavy loads (10k+). Some people think that the LLY cannot do it without getting hot and overheating.


Anyone that has successfully towed on hot days up long steep grades with a good heavy load is encouraged to post their experience. How did the truck perform? Did you seem to be performing worse, the same, or better than brand "D" or brand "F" that were working the same road?


Please post details such as where and when, what you were towing, how much weight and what the outside conditions were, as well as how the truck performed temperature wise. We wanna know your story! Thanks for the input!


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Edited by: TxChristopher

First two weeks of July, temps 90+ from Temecula, CA to Yosemite Valley
and back. Includes the well known Grapevine, and Yosemite is not
exactly level. Cruise control on 60-65 all the way no temp over
1300. Edge/*** 2.



Pulling 13K 5th wheel, loaded CC. Probably over 21K total.



This was before tranny mods.



Labor Day weekend after Mike L. magic, same load, Temecula to Wenatchee Wa and
return. Cruise control same, temps same, the reports of
overheating are greatly exaggerated in my case.


Edited by: mrmagu

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Good EGT's there, what about the engine temps? Get anywhere near 220*, or 225* or more? Or did the truck basically hold the line on engine temps?

Every test I have ever read about in magazines etc have said the truck gains about 5*, but that seems to be normal as the other brands do that too.

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Edited by: TxChristopher

Back in July towing about 10000# from Albany to Buffalo, up the steep hills the highest engine temp I ever got was 202 at 85 degress outside.

I tow 14,000-15,000 around our small hills on 2 lane roads.


Don't see any real difference between the LLY and my previous 7 LB7s.


I do have a 20-25 degree temp difference between the factory gauge and the attitude ( attitude is lower) http://www.dieselplace.com/forum/smileys/smiley5.gif


The engine fan does cycle on some of our hills.


W/ J/A on level 1 it really tows better.

Did not notice any out of line engine temps. Was only casually
watching that, more aware of EGT's because of Juice. All in all, no
significant difference between LLY and LB7.

In May towed 10K+ California to Branson Mo., I-70 through the Rockies and back I-80 with a 2002 D brand following all the way. Never saw over 210 degrees engine or 1400 EGT. Both trucks had about the same load (I was maybe 1k heavier) and both were Edge equiped. Neither could leave the other behind. My Edge was the first Beta. In Sept. did CA to KS and back. No problems except had to remove the Edge. It kept limping the truck. Stock was fine.

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What hp level were you running the edge on while towing? Anyone else wanna post what hp level they were running their box/programmer at while towing?

These are good reports, hopefully more people will find this thread and be able to give good results from their LLY.

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Ran to Kentucky and back (5000mi) with 17,000lb combined weight, TTS Tow, no cat. Mostly 75mph (even through mountains), temps often over 100 deg (111 in Needles). One spot coolant temp got hot, "Coolant Temp High" or something like that on the DIC, but this was 80mph up a 6% grade at over 100 deg, slowing down to 65mph allowed temp to drop. My gasser would have blown a gasket trying to do that.

I ran level 1, 2 or 3 depending how close the Cummins was.

There's steep hills between Albany and Buffalo?

going to sturgis for the harley run towing a 26 foot toy hauler with two bike got hot at every grade had to pull over and let it puke in the mountains north of salt lake and mpg 6.5-7.0 tops 200 miles to a tank was the best I could get

going to sturgis for the harley run towing a 26 foot toy hauler with two bike got hot at every grade had to pull over and let it puke in the mountains north of salt lake and mpg 6.5-7.0 tops 200 miles to a tank was the best I could get


Something ain't right. I towed a 24' enclosed car hauler with spares and the racecar to Vegas and back in the summer, and got 11mpg and zero cooling problems. And I drive like an animal.

the baker grade was the first sight of problems my dash was lighting up like a christmas tree the trans hot light coolant hot light came on.hey Mcrat I live in chino and my mpg was so bad I filled up in chino and filled up in baker then had to refill in mesquite nv

I tow a Tall 10,000 Lb. fifth wheel over parley's summit (long 6.5% grade) with absolutely no problems at all. Trans temp & coolant temp never get over about 200 Deg.. When the fan kicks on high the temps don't climb at all. outside temps in the 90s


Towing mileage is about 11.5 MPG at 70 MPH unless I am pulling the really big grades.


The LLY has been an awesome motor, It pulls like a team of Clydesdale's, and I don't even have the Edge or propane yet!http://www.dieselplace.com/forum/smileys/smiley4.gif

We pulled 26' Toyhauler full of Atvs' and gear and truck full of people and gear, prolly around 15,000 lbs ? and never remember seeing it get over 210 on the guage. Had the Quad module at that time running low and middle setting ( i think 50hp and 90 hp) .Temps up to 90 degrees outside and some driving in mountains. Got like 10.5 to 11mpg ! Oh yeah , now that i have the Edge monitor it reads like 190-195 when the dash reads 205-210 or so ! Wonder which guage is correct?

the baker grade was the first sight of problems my dash was lighting up like a christmas tree the trans hot light coolant hot light came on.hey Mcrat I live in chino and my mpg was so bad I filled up in chino and filled up in baker then had to refill in mesquite nv


Yeah, the Baker grade is the same one I went up at 80mph last summer with no temp issues. And I didn't have to refuel until Nevada.


Hard to diagnose but it certainly doesn't run like mine does.

Socal, I don't know you. Don't take my comments as gospel. I would look no further than your signature to define why your truck does not perform as others do in warmer weather. Without having more details it says "constricted front end airflow".

Also have billet grille and of course billet bowtie to match. I did notice it to run a lil higher temps after install of the grill.

Also have billet grille and of course billet bowtie to match. I did notice it to run a lil higher temps after install of the grill.

Are there any mountains in Kansas?

Also have billet grille and of course billet bowtie to match. I did notice it to run a lil higher temps after install of the grill.

Are there any mountains in Kansas?


I don't know but he does have some 'OCEAN front' property for sale http://www.dieselplace.com/forum/smileys/hihi.gif

Also have billet grille and of course billet bowtie to match. I did notice it to run a lil higher temps after install of the grill.

Are there any mountains in Kansas?


Why sure , we have them right next to the Atlantic bay ! http://www.dieselplace.com/forum/smileys/smiley2.gif


Naw, went on a long trip to Idaho and Wyoming.

going to sturgis for the harley run towing a 26 foot toy hauler with two bike got hot at every grade had to pull over and let it puke in the mountains north of salt lake and mpg 6.5-7.0 tops 200 miles to a tank was the best I could get


Hey socal,,, Once you got past the Rocky Mountains did you have any more heating problems?????

Socal, I don't know you. Don't take my comments as gospel. I would look no further than your signature to define why your truck does not perform as others do in warmer weather. Without having more details it says "constricted front end airflow".


the grill was taken off before the trip to sturgis and has not been on the truck the fan was on towing or not with the grill so I returned it to the dealer

going to sturgis for the harley run towing a 26 foot toy hauler with two bike got hot at every grade had to pull over and let it puke in the mountains north of salt lake and mpg 6.5-7.0 tops 200 miles to a tank was the best I could get


Hey socal,,, Once you got past the Rocky Mountains did you have any more heating problems????? the rest of the trip was nice the fan did not come on that much thru wyoming but my mpg were bad. the temp stayed at 210 and the trans was 200-210

I was referring to the bumper and winch as well.

Thanks socal,,, I was pretty sure that was what you were going to say.... We need all the lly owners to have a convention next summer on the west side of the Rocky Mountains pulling there full size travel trailers... That would turn up the heat on GM just a little. ha!!

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Yeah I was lookin at all that stuff too.

But I think masterp2 has hit on the real reason, although I think he may reorder the souces and make this one reason #1

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http://www.dieselplace.com/forum/uploads/socalLLy/2004-10-31_223932_chevy03_front_l.jpghttp://www.dieselplace.com/forum/uploads/socalLLy/2004-10-31_223250_chevy03_front_130.jpgI was referring to the bumper and winch as well. the opening in the bumper let more air then the stock bumper and the grill is wide open .you sound like my service advisor.dont take that the wronge way I think you are very smart and injoy reading your posts.but there are more people with the same problem not just us with grills or bumpers Edited by: socal LLy

I like that. Clean looking. I was picturing a winch on top of the bumper. Anyway, it can be a real headache to hear someone tell you it's the new "obstruction" when it clearly looks like it wouldn't be. Windtunnels tell some strange stories though. I would not discount this as a contributor, FWIW. Any surface in front of the truck, slows air down.


I would like some of those getting hot to consider another possibilty, it ranks among the least obvious.


This may not be the place to discuss this, it just occurred to me just now while thinking about windtunnel testing.


The evacuation (low pressure) at the bottom and rear of the engine compartment is important in enabling air flow thru the stack and engine. We all know that these trucks come with a low angle of attack from the factory, the back stands up pretty high over the front. Some of the mods we do reduce that (cranking torsion bars). High 2K Pin weight will take 2-3 inches away. My feeling is that allowing the trailer to bury the back end may be detrimental to stack airflow, if the pressure back there is changed by it. And if at all, I have no idea how much.


Heat created-heat rejected=thermal excess.


The first number is increased with the load/speed/programs/grade/driving habits and lots of other things, the second number is reduced by obstructions/pressure changes/part failure/OAT etc.

MasterP,


You may be on to something. Do you know if they field test trucks before they put them on the road? ie- put a trailer behind it and go, or do you think it's a #'s game. this + that - b+G multiplied by tangent of this means this truck has 310 HP and 590 ft. lbs. of torque and is capably of towing this much weight with NO problems. If they use a dyno to test towing capasity and NOT an actual trailer they could never duplicate tongue weight nor it's effects on the chassis/angle. HUMMMMMMMMM I wonder if GM would like to hire me to test trucks for them. AHHHHH what a bitchin job.





XR-Freak

XR, don't kid yourself. That job would go to the brother or brother-in-law of one of the execs! http://www.dieselplace.com/forum/smileys/hihi.gif It's not what you know but who you know! http://www.dieselplace.com/forum/smileys/smiley2.gif


Does GM field test these trucks, likely so. Do they field test them in every conceivable situation, highly unlikely. JJ http://www.dieselplace.com/forum/smileys/smiley4.gif

Bumping this back up, anyone else out there towing heavy have any input. JJ http://www.dieselplace.com/forum/smileys/smiley4.gif

Last weekend I took a two horse bumper pull loaded with two horses and all the gear, probably not more than 7000lbs (not heavy, but dont have the goose installed yet), over I70 from Denver CO to the western slope. 3 mountain passes over 9000 ft (Loveland, Vail and McClure). Running 70-75 I never saw engine temps above 205*, although the attitude did record max as 214*, tranny never got above 190* or so. EGT's would climb to 1200+ quickly when running hard. I had the alarm set at 1280* with defuel at 1250*. Ran most of the time on level 2, also ran stock setting to see the difference. I ran hard to see what the truck would do (less than 1000 miles when I started about 1800 now). The alarm went off when my Fiance was racing a Tundra up the East side of Vail and EGT's went to 1320* or so. Outside temps were not more than 40F.


I didn't pay too much attention to the boost but I am pretty sure it ran into the 20's fairly easily. I am going over again this weekend so I will watch the boost more carefully (will not be towing though).

colodmax, we need for you to push it pretty hard on one of the longer climbs at 9000 ft to see what the boost is, say 2900-3000 rpm's. We're trying to confirm whether GM allowed for lower boost at higher altitude. I think I said that right. For more info check out the LLY overheating post. JJ http://www.dieselplace.com/forum/smileys/smiley4.gif

Yeah, I planned on it. I have been following the overheating
discussion, I will see if I can keep people out of my way long enough
to get the higher r's.



Also I have seen several postings saying the GM engine temp gauge reads
higher than the attitude. I see the same thing up to about 170*
or 180* then they both read very close to the same. Just an FYI.



I also agree that paying 50K for a truck that I have to keep my foot
out of (unless it's to keep from running over a rice grinder) is
insane. I will do whatever I can to help get to the bottom of
these issues.



D.

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By all means post what data you can, the more the better. I have started hitting GM to get a reaction, we will see if they care or not.

Anyone else have towing data, especially boost figures at altitude?


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I Have a 04 chev. lly that has overheated since the first day I purchased it! I tow a 38 ' 5th wheel at 15K lbs. I have to date destroyed 2 motors to hopefully get gm to give me a buyback and realise they have a problem! I am now waiting for my arbtration hearing. I have talked with several GM reps and I was told thatthe GMC's don't have the same problem because of the front grill opening! And they say if i remove my right headlight it will solve my overheating issues!!!
Anyone else hear about that

Yes i heard about this (removing your right headlight several months ago) wierd isn't it. I thought it was a joke but the service manager at my local dealership has an LB7 and he said it was true. I couldn't freakin believe it. I was seriously affraid to post something that rediculous for fear of "alpha abuse" but since you broke the ice i'm right behind ya Russ.

Eric