Attach a garden hose to the upper rad hose and run water until it runs clear. You might use a drain pan or bucket under the lower rad hose. Tap water has minerals in it so it should be flushed again with distilled water.

 

You would have to do it before removing the old radiator.

 

Oh well on that one...

 

The shop replaced my rad with the cheapest one they could find. It fit except they had to cut away a good piece of the shroud. Not really trusting the work I flushed, including using a garden hose in the heater hose. The happy ending is now my coolant is a light clear green, very reassuring compared to the brown gunk that filled the coolant and bottom of my old radiator

 

I'm surprised the shroud had to be modified.

That brown sludge is likely the consequences of the original Dexcool before it was modified.

 

Exactly! As I understand it, the original DexCool formulation did not like to be run low and have air in the system. Hot oxygen reacted with the additives to make the brown gunk. So much for extending coolant lifetime!! I do use the newer DexCool in everything that originally came with it. I also watch the coolant level. Never a problem. I hate to admit it but I have original Dexcool in a 2006 Pontiac G6 that I bought new. 80k miles - no brown gunk.



​​​

 

I wound up getting a stock replacement from DENSO. (Rock Auto) It fit right in but the cooling fins were a hair smaller in area for my fan setup so had to modify that. It came with the quick connect fittings for the Trans cooler but the threads were different then my current aftermarket. The Oil coolers were the same threads and I reused my quick connects. Spoke with "BE COOL" radiators and they are still made in the U.S. and quoted me about $650 for a new one in aluminum but would need to send them mine. I didn't want to wait that long. Saving my old core for next time. I never heard back from GRIFFIN and Ron Davis quoted me $1600.00 so that was out. The local radiator shop seemed disinterested in building me one and did not even attempt to give me a quote. All good for now...

 

I'm sure you will be happy with it!!