I just got my Prestone leaking problem fixed today... We changed the intake's gasket, the water pump, and, since we were there, the thermostat... But, the guy that did the works, pus in pure Prestone, without even diluting it. He said it is better like this. Is it true or not? Thanks a lot, I'm a newbie so don't laught at me See ya

 

you need to dilute it to about a 50/50 mixture.
straight anti-freeze is not able to absorb as much heat as a 50/50 mix, and can cause you overheating problems during warmer weather.

 

yes its tru pure antifreez is bad!!!!
also in extream cold temps it can jel up too thick and cause problems.
to prove what jeff said,,,,,its all about heat transfer......the 50/50 mix will take on more of the heat which is good cause the heats got to go somewere and if you use all antifreze it wont absorb AS much heat as the 50/50 mix leaving the heat in the block,,,,instead of tranfering it to the rad to cool.

Its just common sence any gel product or thick product holds heat in "longer" then a thiner liquid. A thinner liquid just trasfers the heat faster.