NickBeek

Are the codes fan performance related?

t-boe

Those are always off. Mine is consistently off by 2-4 mpg.

judge88

by gauge i mean temp. check earlier post you will see it says hand calculated mpg. im done with this post.

joesixpack

I don't have the electrics, but I guarantee you they won't cool as much as the belt driven fan, fine if your not towing in the heat, and for the third gen's they are already very efficient, and cool high hp very well.
For the play truck, sure, for the workin truck forget it.

Speed Shift

Reason: Being a baby.

Anyway... this should be a good post, I was considering the same thing.

I took a look at Flex-a-lites instructions and they show an adjustable thermostat, which is retarded becuase as everyone knows the thermostat will control the temp no matter how much the fans blow. They say this kit is not for heavy towing..... like above 18k(truck and load). Hell thats as much as just my truck and trailor weigh alone.

This would be a cool kit for a race/dyno/sled truck but as for a working daily driver, I think the money can be better spent else-where. Oh by the way, your check engine light may stay on, so you will need to see a dealer...

http://www.flex-a-lite.com/auto/264-98264.pdf

CamperAndy

Judge least you be Judged a baby. That's too much.

I have no problems with my engine driven fan but if and when the clutch fails I would really consider the flex lite.

Looking at the operational settings and feedback for the viscous clutch it sounds like who ever makes an electric replacement has some work cut out for them to have the fan operate under the same requirements.

I am very interested in is the AC on reaction, currently the fan engages when ever the AC is turned on, anyone know if this happens with the flex lite or does it just wait for the radiator air outlet temp to get up to a certain level??

dozer12216

As others are saying 50 degree drop is not normal or acceptable. Bad thermostat or something. 2 MPG better is just amazing as others are posting only .1 or .2 MPG better with no fan at all in some areas. MY personal test several years ago with a gasser only saw .1 MPG maybe improvement. If that is what you actually got without changing loads, driving habits, or even bragging rights, THEN FINE. I think many of us have a great deal of trouble understanding the HOW of better milage. Many of us have tried various milage improvers with sad results, and we tend to be very skeptical, to say the least. I remember cow magnents, and tornado fans, and HHO kits to mention a few. On the other side of coin, I just put new injectors in my 2nd gen and improved milage from a lifetime of 15 to a current 20+ MPG hand calculated. Oh, yes, pulling a trailer also.
In closing, glad you got the extra milage, but you need a theromstat from your description. I suspect your extensive mods somehow help accomplish. Just wish I could duplicate your results also. A thread from Running_Joe66 also alludes to extra milage although he never gave the particulars. His was more about reliability and was a 1st gen unit. JMHO and trying to defuse for all.

Speed Shift

They come on just like the factory fan...

CamperAndy

That was why I asked, you mentioned the fans had an adjustable thermostat. The factory fan clutch does not.

garbri

Perhaps Judge88 had a defective fan that was malfunctioning, thus causing higher operating temps and/or lower mileage than normal.

Stranger things have happened to me on better days.

I'm just sayin'...

ZacMan5712

i read an article in a magazine about a real world test on an 03 and they confirmed 1.12 mpg gained (average of highway/city driving). but it did say flex-a-lite didn't recommend towing loads in excess of 18,000 lbs. regularly.