Cooling system while towing

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by mjfubar101, Feb 28, 2014.

  1. mjfubar101

    mjfubar101 New Member

    I have a 2001 Chevy 1500 HD 6.0 with 4.10 gears and was wondering what you guys have done to upgrade the cooling system for towing. With some steep hills and hot weather in my future towing my car and all my gear I want to make sure I don't overheat.
    I was thinking a new rad and electric fans, but was wondering if anyone has a more direct answer or how to or something. Also wondering about a larger trans cooler?
  2. j cat

    j cat Epic Member 5+ Years 1000 Posts

    when you tow the transmission adds more heat to the radiator. with a larger tranny cooler this is all you need change to keep the temps in the normal range. this is if you are towing a load total that does not exceed your vehicles rating.

    when towing you must use 3rd gear. do not use 4th gear. this keeps the tranny from over heating.

    fans if installed do not work above 40 MPH also GM does not consider fans[electric] as heavy duty cooling... since you have an old vehicle just to be safe replace the fan clutch.

    you do have the rear diff for heavy load use on hill country..
  3. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Like posted Id upgrade the trans cooler to keep heat and wear under control there.
    A product Ive used for years in the radiator is called "Water Wetter" it lowers the boiling point of the antifreeze and keeps it running a few degrees lower.
    Water Wetter is made by Redline Oil company.

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    As mentioned by j cat and tbplus10.......look at going with a Larger Trans. Cooler, and Tow in 3rd as mentioned by j cat.....also use the Tow/Haul Feature, Here is How-n-When to use Tow/Haul,

    The Purpose of the Tow/Haul Mode is to:
    ***Reduce the frequency and improve the predictability of Transmission shifts when pulling a heavy trailer or a large or heavy load.
    ***Provide the same solid shift feel when pulling a heavy trailer or a large or heavy load as when the vehicle is unloaded.
    ***Improve control of vehicle speed while requiring less throttle pedal activity when pulling a heavy trailer or a large or heavy load.

    Automatic Transmission equipped vehicles are provided with a button at the end of the shift lever which when pressed enables Tow/Haul.
    ***When the button is pressed, the Tow/Haul has been selected. Tow/haul may be turned off by pressing the button again, at which time the indicator light on the instrument panel will turn off.
    ***The Vehicle will automatically turn off Tow/Haul every time it is started.
    ***Tow/Haul is designed to be Most Effective when the Vehicle and Trailer Combined Weight is at least 75% of the Vehicle’s Gross Combined Weight Rating (GCWR).

    Tow/Haul Is Most Useful Under The Following Driving Conditions:
    ***When pulling a heavy trailer or a large or heavy load through rolling terrain.
    ***When pulling a heavy trailer or a large or heavy load in stop and go traffic.
    ***When pulling a heavy trailer or a large or heavy load in busy parking lots where improved low speed control of the vehicle is desired.

    ***Operating the Vehicle in Tow/Haul when lightly loaded or with no trailer at all will not cause damage.
    ***However, there is No Benefit to the Selection of Tow/Haul when the Vehicle is unloaded.
    ***Such a Selection when unloaded may Result in Unpleasant Engine and Transmission driving characteristics and Reduced Fuel Economy.
    ***Tow/Haul is Recommended only when pulling a heavy trailer or a large or heavy load.

    This Thread below is regarding the swapping out of the Factory Trans. Cooler, and the Installing of a Larger Trans. Cooler,
  5. mjfubar101

    mjfubar101 New Member

    When you say stay in 3rd gear do you mean not to put it in tow mode and in drive and just put it in 3.
    Ya I know the fans don't matter over 30-40mph but I was wondering if it frees up the motor some as well as the shroud. But what about a larger radiator? Anything available?
  6. j cat

    j cat Epic Member 5+ Years 1000 Posts

    tow mode should be used when towing . I did not think I had to say that ......then you also only use 3rd 4th gear /overdrive ...

    electrical fans are not heavy duty cooling ! with a bigger tranny cooler the engine will run cooler and you will get more power ...when the engine gets hot you get pre-ignition and you loose power and mpg...

    you must also use 93 octane when towing,,, I do ! 93 helps reduce the KS from retarding the timing and power... normally I do not use 93 with normal light loads only when towing.

    forgot to mention the radiator/coolant cap...make sure you have no leaks and the cap holds pressure. no pressure the coolant will boil and then the temp will spike upward ..
  7. mjfubar101

    mjfubar101 New Member

    Yes of course I know to use tow mode, I was asking about being in D or in 3. Electric fans are better than mechanical, although I can see a better tranny cooler being better while towing as it will have an affect whereas the fans will not, unless I am parked or going really slow. Also remember I'm in Cali so no 93 anywhere to be found.
    That's a good idea about the cap I will look into that, any thoughts about the radiator being as old as it is and a replacement though?
    Last edited: Feb 28, 2014
  8. j cat

    j cat Epic Member 5+ Years 1000 Posts

    electric fans better than mechanical well that's your opinion not my opinion. again GM considers mechanical fans as heavy duty cooling.
  9. redvett

    redvett Rockstar 100 Posts

    You have a 1500HD thats basically a 2500 hence the 6.0L and 4L80E transmission. Check for RPO "KNP" HD trans cooler in the RPO decal in the glove box. Cooling system will be OK if in good working condition. Has cooling system been flushed lately? If not have it done.
    Max towing capacity is 10300 lbs.
  10. mjfubar101

    mjfubar101 New Member

    Yea I flushed it a month ago, ya trailer, car and load probably max 1500 trailer, 3500 car, 1000 load.
    Might try the oil cooler suggestion from jcat

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