flyweed

Hey all,

I just got done swapping out a leaky radiator in my 2002 GMC Express 3500 passenger van. Pretty easy and straightforward, just tight quarters!

Anyway, a full coolant replacement should be about 20 quarts.....just wondering how much coolant should I add to the new radiator? full to the top? How do I make sure I get the right amount back in, and air purged from the system(bled?)

Thanks for any help.

Dan

canucklehead

I add to the rad till its full, then start the van and let it warm up with the rad cap off. Once the thermostat opens the upper rad hose will heat up......keep adding whatever coolant it will take.....once the top rad hose is hot, then you can put the cap on and fill the storage tank to the hot line......
You put a new thermostat in right.....?

flyweed

Oh yeah...figure I had all the top and front of the van ripped open, I am going to replace Thermostat while I am doing radiator too!! Got it all done, put back together, coolant lines bled out, and coolant topped off..good to go and all works great!

A few things I ran across. My van is a 3500 and the radiator had the rubber coolant hoses, but on the left side it has metal tubes going in..when I disconnected them, some red fluid came out, so I assume that was cooling the transmission fluid..then on the right(driver side) some brown fluid came out, so I assume that was the Oil cooler side...OK..fine...but now, I pulled the radiator out and in FRONT of the radiator, there was another only SLIGHTLY smaller radiator. So if I am cooling the transmission fluid and oil in the main radiator, what the heck is the radiator in front of that cooling???

thanks

canucklehead

The small unit is the aux tranny cooler, behind that is the evaporater, behind that is the radiator.

The tranny cooler line goes into the rad at the top, then out at the bottom then into the aux cooler then out back to the tranny.