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Duramax Fifth Generation: 2011-2016 (LML) Discuss the fifth generation (2011-2016) of the 6.6L Duramax diesel engine & associated components. Engine related discussion ONLY.

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  • 1 Post By gmc502
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Old 01-22-2019, 04:02 AM   #1 (permalink)
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LML electrically activated viscous cooling fan

Living here in Australia.....VERY hot here at the moment. Our daytime temps are up in the high 40's (over 115F).

I've been wondering whether anybody knows this: Would it be possible to add a manual over-ride switch to the electrical cable that activates the viscous fan?

I'd like to be able to activate the fan sooner than the ECM does; say around 95C.

The idea is to kick the fan on sooner and stop the engine getting to a temp over 100C (or 212F).

Just curious if anybody has done this or what the consequences (if any) might be.

Obviously it's not the sort of think I'd forget to turn off....the SOUND of the fan would keep me aware that I'd flicked the switch ON.

All the best from Australia,


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Old 01-22-2019, 08:37 AM   #2 (permalink)
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I'd probe the wires when is running,put the meter on ac volts and see if its reading,only way I could tell if its a pwm signal,then switch to dc and see if its steady.if steady,then you should be able to add a switch.
if you have an oscilloscope,all the better.

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Old 01-22-2019, 10:18 AM   #3 (permalink)
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Have you asked your tuner if that is a parameter they can adjust? I haven't messed with tuning any LML's, but it might be that easy.
2003 GMC Sierra 2500HD LB7 Duramax 4WD Crew Cab SB
310k miles. 8,260 lbs empty. Built motor, and still slow.
2003 Chevy Suburban 2500 LB7 Duramax AWD Quadrasteer
135k miles. 6-speed Allison conversion. Quadrasteer 4-wheel steering.

1982 Chevy C10 Silverado 6.2L Diesel RWD Single Cab LB

115k miles. Built 700R4 automatic, 4.11 gears.

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