Long story short. 2dr 03 Blazer LS 4wd. Had a leak in the tranny cooler in the rad. So...new rad installed. Flushed the tranny good, finally after running 4 gallons thru ,it's clear red once more and shifting better then ever! Problem is...I flushed the bejesus out of the rad. Water/simple green HD mix, let it get up to temp. Cool down, drain, and then repeat with just water. Drain flushed the rad multiple times with hot water. Sealed up and filled with 50/50 prestone. Problem is I still have a tiny bit of the old prestone/tranny fluid mix (pink milkshake)showing on the surface in the rad fluid in the rad and hints of it in the overflow bottle. Can I just leave it as is?? Guessing there was a bit still in the heater core that I didn't get..when I say tiny bit, I'm talking maybe 2 tablespoons total tops! Or do I really need to totally purge it? All seems to be working OK temp is good, heater blows hot.

 

Ideal would be to completely purge, flush, and refill, but honestly I'd probably just do my best to remove that residue and carry on.

How hard would it be to remove that residual surface fluid from the Rad filler and overflow? Maybe with an old syringe or a turkey baster type tool?

 

When I did my cooling system flush long ago, I removed the overflow tank and washed it out. Turned out there was lots of sludge in it, much more than I thought. It was stuck up in the narrow parts that I never would have been able to reach without removing it.

To get it out, you probably have to remove the ECM etc. but at least you can get to it from above. You might try that.

 

Yup did that just lifted the ecm out of the way.. overflow was really grungy inside. Got it sparkling. Ended up last night getting most of what's left in the rad with a tiny crevice tool hooked to my vacuum and some paper towel to soak some up. The little thats left in the overflow tank I'm going to disconnect from the rad the flush with hot water and cleaner then flush again with just hot water till its clean. Then add some fresh prestone. Right now it's at the garage for power steering hose replacement. Didn't realize till too late that the hoses with all the corrosion I was moving fairly roughly while installing the lower oil cooler line in the rad where power steering. Of course I created a leak!!! And it's too cold now for me to try to do it myself. Only have a few hours in the middle of the day to do work (school bus driver) so decided to give the garage some business. But it has been a learning experience. At least the rad went in smoothly, the rad flush went well (shifting really good) and heating is top notch.

 

I believe that there is stuff out there that will absorb oil but not water. I believe that goose feathers are one of those things. New Pig might have something as well.

 

This, +1.

George