Hi i am new to this message thing, wanting a 05 06 2500 duramax. test drove one to day it drove good and was strong accelerating. got back to dealer and antifreeze was all up in the right front wheel well. the temp never got over 170 175 deg f. also the coolent resivour looked like there was some black residue inside of it. ( is this a common problem or an issue?) there was some extra ***** located on dash panel, sales guy said it was for a program tuner. is this somthing to be coserned about.
i drive a 95 2500 w/454 & auto trans. fuel milage is killing me, this is the reason Im looking at deisels.

Thanks for any input on this

I love my trucks, have never been without one..

 

It sounds like the oil cooler went out.
as for the switches, that doesn't sound like a tuner, most tuners have built in switches.
For the switches, I would track them down to see what they do.

 

Thanks for the reply.
if the oil cooler was leaking would it have antifreeze in the oil also?