I have not found any drains on the block and I searched on line as well and didn't find any information to any. What I had to do on mine that had both types mixed, was to flush it out the best I could. I use distilled water and what normally took me about 6 gallons, I ended up using 10. I pulled the lines going to the heater core and cleared those by them selves. Then I cleared the block and had the lines that went to the heater not connected and had removed the thermostat and flushed the engine. When the water was finally coming out clean I drained it and then filled with Dexcool.

 

I can offer some help. The 2nd photo is the driver side of the block. The large brass plug at the front is a water jacket drain - takes a 17.5 MM Allen wrench.

The first photo is the pass. side, though the block is upside down - Sorry, only shot I had handy. You can see the plug at the rear of the block - it takes an 8 MM allen wrench. It's facing up in the photo, but is facing down in the truck.

 

Are they low enough to drain the block of water or do they still leave water in the bottom of the block? I thought I read someplace they are not like the old small and big blocks with drains in the lower part of the block that allowed you to get most of the water out. On the LS blocks it left quite a bit of water in the block still? I don't know and was going by what I had read on the ole innerwebs and we all know how accurate that is.

 

That is good to know. Thanks

 

Thanks for help, will let you know how I get on with flushing
Richard

 

Given this information you have choices on how to completely flush the cooling system. It can be done without removing the plugs from the block and performing multiple cycles of draining the radiator/refilling with fresh water/running the engine until warm (to ensure the thermostat opens)/cooling off the system/draining the radiator until the drained fluid is clear. The process is included in the GM service manual. You can expedite the process by temporarily removing the thermostat and reinstalling the thermostat housing. If your thermostat has not been replaced for some time, I recommend replacing it as part of the process. I've seen a couple with many years on them (not to be confused with miles) in which the nonmetallic material was severely degraded.

From my experience, the amount of liquid captured when draining both the overflow tank and radiator on my 2005 SSR is slightly more than six quarts, which is almost half of the 13.7 quart total cooling system capacity. So if you use the multiple drain/refill cycle method until the system fluid is clear, adding six quarts of undiluted antifreeze to refill your radiator and overflow tank will bring you pretty close to having the manufacturer’s recommended 50/50 mix of antifreeze and water in your system.

 

I gave ours a cooling system “refresh”, replacing both radiator hoses, heater hoses (Mike’s upgraded kit), thermostat, surge tank and cap.

I used the multiple drain/refill cycle method @snomuncher recommend until the water ran completely clear. Used about 6 gallons of distilled water. Filled to a 50/50 mix with DexCool. Hasn’t gone over 208 degrees since.

Robert (@rcg530) has some great cooling system DIY videos:

SSR Videos – Simple Engineering, LLC

simple-engineering.com