09 Prostar running hot

[Rawze]

(04-09-2017 )Mt farmer Wrote:  What does it mean, when the radiator is anodized? Used new red Detroit coolant when I put the new radiator in. Used the same stuff when I changed the thermostat.

basically its when something has built up on the surfaces inside the radiator the lower its heat xfer effects. Sometimes it is anodizing (discoloring of the metal from reaction with the coolant or water, etc. lowering its overall heat xfer effects), or could be a buildup of sludge, etc.

It is common for the small radiator in APU's to get internally anodized and not be so efficient. I had one do this and it went from dropping the temperature by 30-40 degrees to only being able to drop the temperature 15-20 degrees and it was just enough for the APU to have constant heat issues after an hour or more of run time. I found this by using a heat gun, comparing input and output temps both before replacing the radiator and after. The inside of it looked clean but it was discolored badly. On mine, the day I tested this, it was only dropping the coolant by about 18 degrees across the core, then after I replaced it, it immediately started dropping the temps by 40+ degrees across the new core. I have since seen this on a few other trucks APU's as well.


You say it gets hot quick, so that is not likely simple anodizing in your case unless there is blockage or its design is less efficient than the factory radiator, who knows. Your original post makes it seem like you have a serious cooling issue or a serious issue with the engine producing heat quicker than the system can keep up with.