coolant question

[Delorean17@xxxx]

Hello, Can someone please clarify this for me?

Will running straight antifreeze through your car cause it to get hotter? 
Last week I had a coolant leak and lost nearly all of it. I didn't have any 
water so I fixed the leak and put in straight antifreeze.(almost 2 gallons if 
I remember correctly) I have left it this way because a friend said it 
doesn't matter at all, mixing it just saves money. Is this right?
I cannot figure out why my fans are still on at 60 MPH. The needles 
stays just a hair above the 2nd white line and the car is not overheating but 
it seems to be just abit hot enough to start the fans. I have a new 
otterstat which turns the fans on at a lower temp(specialtauto.com) but I 
know they shouldn't be on at 60MPH when its only 65. I have the overheat 
protector installed. The water pump is fine, I checked it out when I 
replaced the hoses with silicone ones.

Thanks list
David