Can Heavy towing blow the engine?

rrh13441

Member
Mar 24, 2022
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6
Can heavy towing cause my LML to blow a head gasket with All other parameters are good and no other issues.


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Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
31
28
48
Western MA
www.matpa.org
Define "heavy". Heavy within rated tow capacity and up modest inclines, or heavy as in trying to tow a D8 up the Ike Gauntlet? Bone stock trucks OVER TIME have been known to lose head gaskets, but it usually takes many years and some last longer than others due to varying degree of factors. Towing heavy, adding power, etc definitely speeds that process up. All that said, just towing something heavy (within the manufacturers stated limits) will not in and of itself wipe out head gaskets. Not sure what year the truck is or mileage, but since the LML came out in 2011 there's a possibility there's some age and/or normal wear and tear on the motor from standard use that contributed to the situation. Some say while Dexcool is an "extended life" fluid, it should be drained/flush to avoid issues with radiators and head gaskets (was that ever done)?
 

rrh13441

Member
Mar 24, 2022
45
0
6
Define "heavy". Heavy within rated tow capacity and up modest inclines, or heavy as in trying to tow a D8 up the Ike Gauntlet? Bone stock trucks OVER TIME have been known to lose head gaskets, but it usually takes many years and some last longer than others due to varying degree of factors. Towing heavy, adding power, etc definitely speeds that process up. All that said, just towing something heavy (within the manufacturers stated limits) will not in and of itself wipe out head gaskets. Not sure what year the truck is or mileage, but since the LML came out in 2011 there's a possibility there's some age and/or normal wear and tear on the motor from standard use that contributed to the situation. Some say while Dexcool is an "extended life" fluid, it should be drained/flush to avoid issues with radiators and head gaskets (was that ever done)?
I tow a grand design 348 M that has specs of Dry Weight 13,400 lbs., GVWR 16,500 lbs., Hitch Weight 3,100 lbs. I have a 2012 GMC Sierra 2WD Crew Cab Duramax LML with 130K that has the exhaust and EGR deleted, and an H&S Performance Mini Maxx Tune. when i did the delete I changed out the radiator, intercooler, Water Pump, t-stats, Pullies, Fan Clutch. When I first took it out after the delete towing my 5th wheel the top radiator hose clamp failed and caused an overheat. The truck never went into limp mode or anything like that, but once i pulled over it maxed out the temp gauge at 260 for a brief moment and it started to cool down. Since I have been loosing about a 1/2 of coolant now and then but only noticed it statically not under pressure. I have towed with it and it never last fluid could not smell any but it would set in my garage for a couple days or so and i would find a small size, half dollar, coolant puddle under the middle of the truck. Took it in the pressurized it and at first no leak we left it over night and sure enough the passengers head side by the firewall had as small leak. Hopefully when these head gaskets get fixed I wont have anymore issues. Just wondering if towing heavy would do this as well? The shop suggests towing in stock mode but I have seen posts where people are towning heavier than me and have the tune in Performance or Tow mode with no issues. Not sure if I should have my tune in stock or town when towing, My truck is in tow mode and the tune is stock should I keep it like this or will the extra HP be too much?
 

gmduramax

Shits broke
Jun 12, 2008
4,072
248
63
Nor cal
It depends how often you tow. Towing with added power decreases engine life. If you want to tow with a tune an EGT gauge and a 2020 oil cooler should be added. Also a good quality tune is a must.
 

malibu795

misspeelleerr
Apr 28, 2007
8,228
543
113
42
in the buckeye state
I tow a grand design 348 M that has specs of Dry Weight 13,400 lbs., GVWR 16,500 lbs., Hitch Weight 3,100 lbs. I have a 2012 GMC Sierra 2WD Crew Cab Duramax LML with 130K that has the exhaust and EGR deleted, and an H&S Performance Mini Maxx Tune. when i did the delete I changed out the radiator, intercooler, Water Pump, t-stats, Pullies, Fan Clutch. When I first took it out after the delete towing my 5th wheel the top radiator hose clamp failed and caused an overheat. The truck never went into limp mode or anything like that, but once i pulled over it maxed out the temp gauge at 260 for a brief moment and it started to cool down. Since I have been loosing about a 1/2 of coolant now and then but only noticed it statically not under pressure. I have towed with it and it never last fluid could not smell any but it would set in my garage for a couple days or so and i would find a small size, half dollar, coolant puddle under the middle of the truck. Took it in the pressurized it and at first no leak we left it over night and sure enough the passengers head side by the firewall had as small leak. Hopefully when these head gaskets get fixed I wont have anymore issues. Just wondering if towing heavy would do this as well? The shop suggests towing in stock mode but I have seen posts where people are towning heavier than me and have the tune in Performance or Tow mode with no issues. Not sure if I should have my tune in stock or town when towing, My truck is in tow mode and the tune is stock should I keep it like this or will the extra HP be too much?
Weight isn't the issue.
Shop wants it "stock" for legal issues at a minimum.

The breif over heat most likely weakened it. And broght "when" a lot sooner..
Generally the ECM starts pulling fuel/derating at 250° on the '10 and older trucks, id deduct, it's similar for LMLs as well.

Weight isn't the issue.

I would suggest getting at minimum engine oil temp gauge installed and better yet doing the 2020 engine oil cooler upgrade.

As it is not hard to cook the oil with a high sail load.
 

johnmyster

Member
Nov 6, 2023
68
25
18
Lynchburg, Virginia
Our fifth wheel is probably only 9000 pounds loaded and I can see significant oil pressure drop on long grades at constant RPM. In absence of an oil temperature gauge, this indicates oil temps are going up. Be aware that much below 30 psi, piston cooling jets will leave the chat. On some of the hills west of here I could easily make it happen. It wouldn't lead to a head gasket issue but I'm sure an irresponsible driver could crack a piston in short order by lugging the engine into high oil temperatures without piston cooling.

2020 oil cooler and EGT gauge are in my future.
 
Last edited:

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
904
31
28
48
Western MA
www.matpa.org
I'm willing to bet the engine reaching those temps didn't do your head gaskets any favors. If you are having new head gaskets installed it would be a GREAT time to install head studs. The original bolts are torque to yield and should not be reused (although some have done it). A set of OEM bolts (depending on the source) can sometime cost the same as head studs so it's a no-brainer to install the studs as they provide better clamping force (assuming the PROPER install instructions are followed along with any stated retorques). Edit: I just looked up the price of head bolt sets and they are significantly cheaper, yet I still would suggest paying the extra for the head studs as it's the same labor and you don't want to pay that twice should an issue arise and they can be used again.

As for towing with a power adder...If you are on a stock transmission (especially with any significant mileage) I would advise against it. If you have a built transmission with converter and can monitor engine oil temps, I would not hesitate to tow with a QUALITY tow tune.