eallanboggs

iTrader: (1)

Usually the A/C trigger wire is used to turn the fans "ON" even it you haven't yet reached you set point(temp at which the fans come "ON"). That just means that if you turn your A/C on right away the fans will come on before you reach set point. The low temp thermostat only changes the point at which it opens up(sooner-lower temp). It doesn't increase efficiency. You could try connecting the A/C wire to see if the fans speed up when the A/C is "ON". If so, you could use that wire via a relay to keep the fans running at high speed all the time if that's what you are trying to accomplish. The elec fans have advantages over the clutch flex fan. The horsepower used to spin them goes to your rear wheels instead and a side benefit is better gas mileage do to the increased efficiency. If you do have two speed fans it should be easy enough to find out just by hooking up that A/C wire. Use a relay unless your SURE that wire is going to one. Don't put a LOAD wire on the PCM.

OrlandoFL4.8

iTrader: (1)

Thanks, thats kinda what I figured. I went ahead and spliced into the AC wire so that when the AC is on, they turn on high and it makes a big difference. I let the truck get hot in the driveway holding the RPMs at 2000 while parked with hood down and waited till it got to about 210 with the fans on low. Normally, with the fans on low, the temps will just continue to creep up slowly if Im not moving and at idle. I turned the AC on and the fans kicked on high and the temps dropped back down below 200 in a matter of minutes with the hood down. I am still gonna take it in and have my cooling system checked because it shouldnt be getting hot with fans on low with the AC off.

InchUp

iTrader: (2)

You're about half right, but the problem is you're basing this claim off of clutch fans from the old days. The new clutch fans that run off the water pump are extremely efficient nowadays to begin with and create very little drag on the motor. Of course though...there is a minuscule amount that can be calculated, I'm sure, but the gains are not worth a darn. You'd probably end up with a faster truck by taking a **** before you stepped in rather than taking the clutch fan off, seriously. Those small gains don't immediately end up at the rear wheels though, not by a long shot. Electric fans don't just spin by themselves, the energy must come from somewhere. That somewhere is the electrical system charged by the alternator. Where then does the alt get it's power...the serpentine belt powered off the crank. All you're really doing is transferring one load from the water pump pulley to the alternator pulley. Where the electric fan could show it's shining colors here is if the transfer from mechanical force to electrical current (alternator) and then from electrical current back to mechanical force (e-fan motor spinning the blades) was more efficient, but it's not and that is why alternators and electric motors heat up. If the alternator alone could be more efficient, I bet there'd be some measurable gain to switching to an electric fan.

Electric fans have a few simple benefits as to why they are worth the conversion from mechanical to electrical fan. If you throw the cost of the conversion out of the equation (purchase of e-fan, wiring/tune to power the fan and hopefully some form of an alternator or battery upgrade) then one can see the following things; 1) decrease in coolant temps at idle 2) colder A/C at idle 3) de-cluttered engine bay/more room to wrench on the front of the motor and finally 4) on the highway the e-fan is not in use because there is sufficient flow through the radiator leading to the only possible way to see better MPG - not because the e-fan is more efficient, but instead because there's no draw placed on the alternator and electrical system. Those 4 benefits, aside from having the ability to have control over when the fan is off and on and at what speed, are what make the transition from mechanical to electrical fans worth it. I must also add that not having the "woooosh" noise on a hot day at low MPH is nice as well, but then again my 18" electric fan isn't really much quieter when I'm off-road beating on the motor during the summer time.

So, to each their own, but this is the general clump of reasons I go by when making the decision to ditch the clutch fan.

InchUp

iTrader: (2)

To the OP, OrlandoFL4.8, I think the problem is insufficient cooling. Going from the 4.8L to the built 6.0L put a big strain on the cooling system. Have you looked into the 35" radiator and '05 fans instead of the LS1 fans? It is my understanding that most, or all, 6.0L trucks got the bigger radiator. Am I wrong?

OrlandoFL4.8

iTrader: (1)

Not sure, but cant see how going to a bigger/more efficient radiator could hurt anything. Thats why I was wondering if anyone else that did the lq9 swap and used the stock/smaller radiator had any issues?

InchUp

iTrader: (2)

Considering that you'd go from a 28" radiator to a 34-35" radiator, it's a significant increase in volume and surface area for airflow to work on. You're talking about an increase of ~180 square inches of surface area, that's a 45% increase! Plus, the 6.0L radiator is thicker, 1-1/6" compared to 15/16" Napa says. It's worth looking into.

Thechevyman122

iTrader: (3)

the simple fact of the matter is ls1 lt1 fans work GREAT on the smaller pre 2005 and non 6.0 motors. The other engines have a larger radiator that can creat problems with the lt1 and ls1 fans. I have yet to put mine on cause im waiting for the end of summer. Some say the work fine some say they dont.

I would clean your radiator really good (a can of coil cleaner works great which you can pick up at your local ac/refrigeration supply house) and if you still are having problems, you can pick up a set of 05 efans and your current harness will work.

GMCtrk

iTrader: (27)

I swapped the 6.0 and have the little radiator. It keeps it cool great. I'm using the clutch fan.

OrlandoFL4.8

iTrader: (1)

Mine worked fine with the clutch fan too

Zick

iTrader: (18)

My old 03' used the factory radiator w/ 180* thermostat and I had on an older pair of LT1 fans that worked great. Even on the hottest day I never went above 190. If I recall it usually sat around 180-185.