Reversable Fan Blades Question

[g_man]

The little dozer I just bought has reversable cooling fan blades. I know this is common on equipment but I have have no clue what advantage one way has over the other. The previous owner told me to take a floor panel out in the winter to get a little heat on my feet with the fan  pulling air in.
Can someone educate me on the fan blade direction uses.
Thanks.

[Cedarman]

I was told that when pushing debris into a fire, you would want the fan pushing air forward keeping burning debris from being pulled into the engine area.

[ely]

most folks here run the blades in the winter to pull air towards the operator. they push the air away from the operator in the summer.

[mad murdock]

ely has it straight.  They are for reversing airflow over the radiator and engine, mostly for operator comfort, if you are in alot of dust and loose debris, by pushing the air, rather than pulling, it tends to keep the radiator from getting packed up with dirt as well.  It makes a noticable difference on heat from the operators seat with the blades pushing in the summer, and when it is real cold, you can definately feel more warmth with the warm air blowing back(pulling through radiator).

[scsmith42]

My old Cat mechanic (a "good ol boy wiht a 5th grade formal education, but still the best mechanic that I've ever known) advised me to remove the reversible fan from my D8, and to replace it with a straight blade fan (blowing the air from the engine through the radiator and out the front of the Dozer).

His reasoning was that he had repaired/replaced quite a few radiators due to the reversible fans coming apart, but never one from a straight blade fan.  He also stated that the reversible blade fans were not as efficient as straight blade ones, and at least in the south they were not a good option during the hotter weather.

[g_man]

My old Cat mechanic (a "good ol boy wiht a 5th grade formal education, but still the best mechanic that I've ever known) advised me to remove the reversible fan from my D8, and to replace it with a straight blade fan (blowing the air from the engine through the radiator and out the front of the Dozer).

His reasoning was that he had repaired/replaced quite a few radiators due to the reversible fans coming apart, but never one from a straight blade fan.  He also stated that the reversible blade fans were not as efficient as straight blade ones, and at least in the south they were not a good option during the hotter weather.

Good to know - Thanks

[Randy88]

Got 4 machines with reversible fan blades on them, greatest invention ever, Ely got it right but to add, heat on the body in really cold weather is beyond great, blowing forward also blows the dirt away from your eye's some in the summer and it also depends on how things are set up on the machine as to how it cools the radiator some, on my machines the oil cooler is in front of the radiator and if you suck air backwards in the summer it makes the engine run warmer but in the winter it aids in keeping the engine warmer without putting a piece of cardboard in front of the radiator, due to the added heat off the oil cooler being sucked into the radiator.   

As for set blades cooling better vs the reversible blades, the curve is the same on both so I can't see one being better than the other, as for flying apart, never had my reversible blades do it but had two fixed blades crack and go through two radiators, I'd opt for the opposite since reversible blades are heavier built over regular blades and if you bend a blade on a reversible you could replace just one blade, on a fixed you replace the whole deal.   

Also if you have a machine running hot and no air hose around to blow it out I've reversed the fan to help it some and then turned it back again, works for a temp fix to blowing out a radiator, but mine are changed daily in warmer weather of spring and fall, where it can be warm one day and cold the next, I've even switched them several times a day even depending on the temp changes during the day.

[g_man]

Well with luck I'll have it back together next week and I can start to find  out how some of these things work  for my self. I was wondering if it made much difference on the oil cooler/radiator. My oil cooler is in front of the radiator also.
Thanks again.

[Sprucegum]

The reversible blade (or a good version of it) was invented by a neighbor about 40 years ago and he spent the rest of his life trying to get it to market without giving away the patent. He finally got a good deal just before he passed on. That's all I remember at the moment, I should dig up the details