Quote:
Originally Posted by Sand85
My current fan has six blades and I don't see how one more blade would make a difference? 
I have run a 93' Chevy 5.7 with no thermostat and it run fine but I put one in anyways because I was a lot more comfortable knowing it was there. |
If yours is a flex fan(hard to tell for sure from the pics), it probably has less pitch since the assumption is that it will be running at a higher speed most of the time. When it is running at high speed, it pulls enough air to keep things cool. At idle, not so much. Which is where you said your problem is.
The factory fan has more pitch since GM expected it to be mated to a clutch which allows some slippage. But at slow speeds, it moves more air across the radiator. The one extra blade isn't the advantage, the greater pitch is. If you wind up getting an OEM type fan, they usually come in 5 and 7 blade versions. Might as well get the 7 blade if you make the swap. Some flex fans won't mate to a clutch, depends on the fan.
Adding the shroud may fix the problem with no other changes needed.