Coolant temperatures while towing

[L31MaxExpress]

GM has newer PWM brushless fans in the Corvette and Camaro that are 600+ watts. IIRC the Camaro has an 18" fan that is 800 watts. Only fan I could see that might out perform the clutch fan by any metric at normal engine speeds. At say 2,500+ RPM the clutch fan is still going to move more airflow. There are some high end european vehicles using the same Spal motor and fan that also move a ton of airflow. GM has some newer 1500 trucks using a dual PWM motor setup even on the 6.2L although I have no idea on how many watts they draw or how much CFM they pull. That being said even that dual fan setup is obviously not enough to cool the 6.0L or 6.6L gas or diesel in the 2500+ trucks or vans because they still have a clutch fan in those applications. The 6.6L gas is using a HUGE clutch fan blade on it and in the vans even the 4.3L V6 has a fairly large clutch fan on it.

 

[L31MaxExpress]

I have actually been trying to get my hands on a 6.6L gas van fan blade for a while now for some testing. It is 20" in diameter 7-bladed monster and 4.25" tall meaning those bladed have some pitch and surface area to them. No shock there it is cooling a 400+ HP 6.6L V8 in a 7,000+ lbs van with a 10,000+ lbs tow rating.

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[L31MaxExpress]

Same van with a 4.3L V6 gets this 20" 6 bladed fan that is 4.12" tall. Still has a fairly aggressive pitch and a ton of surface area on those blades for only having to cool a 4.3L.

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[Schurkey]

The dual fans on mine are 80W each.

I had the same problem and had to retrofit 95 watt fans

The last time I dicked with electric fans was on a V6 minivan; 2006 Buick Terraza. I was playing with my low-amps probe and a 'scope I'm not real familiar with. I have photos, but I don't remember details very well.

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Upper trace is the fan motor, thinking it's pulling 11--12 amperes on low speed. Lower trace is battery charger, and can be ignored.

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11 amperes x 14 volts = 154 watts, and this is ONE fan motor of the two in the shroud, and LOW speed, not high speed.

Again, I don't remember this very well. I'm thinking that high speed thru the other fuse, was more than double the amperage. The wiring was complex, and I needed this gone from my driveway. The real problem was a failed primary fan motor which I replaced. The secondary was OK. Vehicle kept popping the 30-amp low-speed fan fuse.

30 amps X 14 volts = 420 watts, but that was because the fan motor was locked-up.

GM has newer PWM brushless fans in the Corvette and Camaro that are 600+ watts. IIRC the Camaro has an 18" fan that is 800 watts.

Woof.

 

[whataTRUUUCK]

The last time I dicked with electric fans was on a V6 minivan; 2006 Buick Terraza. I was playing with my low-amps probe and a 'scope I'm not real familiar with. I have photos, but I don't remember details very well.

You must be registered for see images attach

Upper trace is the fan motor, thinking it's pulling 11--12 amperes on low speed. Lower trace is battery charger, and can be ignored.

You must be registered for see images attach

11 amperes x 14 volts = 154 watts, and this is ONE fan motor of the two in the shroud, and LOW speed, not high speed.

Again, I don't remember this very well. I'm thinking that high speed thru the other fuse, was more than double the amperage. The wiring was complex, and I needed this gone from my driveway. The real problem was a failed primary fan motor which I replaced. The secondary was OK. Vehicle kept popping the 30-amp low-speed fan fuse.

30 amps X 14 volts = 420 watts, but that was because the fan motor was locked-up.


Woof.

Thats a big difference from my 80w fans...how much did that whole setup cost u? Did u have to put in a high output alternator also?

 

[Schurkey]

That's the cheap-junk Amazon/Chinese replacement for the OEM fan motor. (Right side in this photo)

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The OEM fan is RIVETED to the plastic shroud. Hadda grind the rivet heads off, and poke the rivet shanks out with a hammer and punch to replace the motor.

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...and then re-pin the wire harness for the second fan, 'cause both fans run off of the same four-wire connector.

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So in the end, all I replaced was the 30-amp MaxiFuse, and the fan motor.

The point I'm trying to make in all of this is that GM uses (much) bigger fan motors to cool a 3.5L V6, than the aftermarket sells to cool a larger V8. There's a reason that I despise (most) aftermarket "electric fan conversions". They're under-powered, poorly designed...they're just expensive trouble. It takes a REAL electric fan motor--or two--to cool a V8. Guys throw the fan and fan clutch in the trash, then spend money to get LESS cooling power in the aftermarket "electric fan conversion". Much like aftermarket disc brake conversions.

 

[Supercharged111]

That's the cheap-junk Amazon/Chinese replacement for the OEM fan motor. (Right side in this photo)

You must be registered for see images attach

The OEM fan is RIVETED to the plastic shroud. Hadda grind the rivet heads off, and poke the rivet shanks out with a hammer and punch to replace the motor.

You must be registered for see images attach

...and then re-pin the wire harness for the second fan, 'cause both fans run off of the same four-wire connector.

You must be registered for see images attach

So in the end, all I replaced was the 30-amp MaxiFuse, and the fan motor.

The point I'm trying to make in all of this is that GM uses (much) bigger fan motors to cool a 3.5L V6, than the aftermarket sells to cool a larger V8. There's a reason that I despise (most) aftermarket "electric fan conversions". They're under-powered, poorly designed...they're just expensive trouble. It takes a REAL electric fan motor--or two--to cool a V8. Guys throw the fan and fan clutch in the trash, then spend money to get LESS cooling power in the aftermarket "electric fan conversion". Much like aftermarket disc brake conversions.

Unless you use a late Lincoln MKVIII fan with its 4000cfm of goodness.

 

[Schurkey]

Sure. A big enough electric fan works just fine. But that's typically going to be an OEM job, because the crappy fans/fan motors/shrouds commonly sold by the aftermarket as "conversions" are lame.

 

[L31MaxExpress]

The last time I dicked with electric fans was on a V6 minivan; 2006 Buick Terraza. I was playing with my low-amps probe and a 'scope I'm not real familiar with. I have photos, but I don't remember details very well.

You must be registered for see images attach

Upper trace is the fan motor, thinking it's pulling 11--12 amperes on low speed. Lower trace is battery charger, and can be ignored.

You must be registered for see images attach

11 amperes x 14 volts = 154 watts, and this is ONE fan motor of the two in the shroud, and LOW speed, not high speed.

Again, I don't remember this very well. I'm thinking that high speed thru the other fuse, was more than double the amperage. The wiring was complex, and I needed this gone from my driveway. The real problem was a failed primary fan motor which I replaced. The secondary was OK. Vehicle kept popping the 30-amp low-speed fan fuse.

30 amps X 14 volts = 420 watts, but that was because the fan motor was locked-up.


Woof.

The heavy duty ~2010 GM police Tahoe fans (7 and 9 bladed fans) that also came on the max tow 1500 GMT900 Silverados with the 6.2L pull 50 amps on high speed. 50 x 13.5 = 650 / 2 = 325 watts each. I had to upgrade from a 140 amp alternator to a 200 amp AD244 that made over 100 amps at idle to prevent the volt meter from practically bottoming out at idle. Those fans were still not enough to cool a 350 with a 34 x 17 x 2.25" dual core radiator when it was working hard. Driving around town with the engine between 1,250 rpm and 2,500 rpm the ac also performed drastically better going back to the clutch fan.

 

[L31MaxExpress]

The last time I dicked with electric fans was on a V6 minivan; 2006 Buick Terraza. I was playing with my low-amps probe and a 'scope I'm not real familiar with. I have photos, but I don't remember details very well.

You must be registered for see images attach

Upper trace is the fan motor, thinking it's pulling 11--12 amperes on low speed. Lower trace is battery charger, and can be ignored.

You must be registered for see images attach

11 amperes x 14 volts = 154 watts, and this is ONE fan motor of the two in the shroud, and LOW speed, not high speed.

Again, I don't remember this very well. I'm thinking that high speed thru the other fuse, was more than double the amperage. The wiring was complex, and I needed this gone from my driveway. The real problem was a failed primary fan motor which I replaced. The secondary was OK. Vehicle kept popping the 30-amp low-speed fan fuse.

30 amps X 14 volts = 420 watts, but that was because the fan motor was locked-up.


Woof.

The way GM wires their dual cooling fan setup usually results in a Series/Parallel arrangement. Low fan speed would thus be 1/2 of the amperage draw per motor since the resistance is doubled and each motor gets 6 volts. The wattage on low speed would thus be 1/4 of what it is on high speed. The overall amperage draw of both fan motors is cut to 1/4 of what it was on high speed because of them shifting to the series arrangement. Unless you verified low speed was putting 12V to the fan, you are likely looking at 10-11 amps at 6 volts. That would closely fall in line with the 12.5 amp draw I saw on low fan speed with Tahoe fans in series. 50 amp draw on high speed with the motors in parallel and 12.5 amp draw on low speed with the motors on series. The first I remember seeing the series/parallel dual speed dual fan setup was on the 90s LT1s. Prior to that GM dual fans ran independently at full voltage to each motor. The dual speed arrangement running both fans actually improved cooling compared to 1 fan running at full speed and was much quieter. On the low speed setting the fans turn about 1/2 rpm compared to the high speed setting.