how can i flush a radiator while its out of the car? i bought a used radiator from a member on here for my v8 swap and the radiator has some sand like material in it and i want to flush it out before i install it because i dont want that stuff floating through my new motor or waterpump.

 

Stick a garden hose in the top and run till water comes out clean.

 

yea also good time to check if theres any leaks also

 

If anything is stuck because it won't go through it, turning it upside down and reverse flushing could help with that

 

Lay it on its back, ports up.
Fill with water & the store stuff flushing chemical to break loose any deposits (i'd suggest a home remedy but dunno of any vinegar?)
Let it sit & soak.
Repeat a couple of times.
Install & use DISTILLED water. Garden hose water can have calcium & such which can clog the radiator & reduce its efficiency help.

I flushed mine a few months ago & dropped me temps from borderline overheating with the AC off, to 210 with the AC on. I probably needed to flush (only flushed it 1 soak cycle) it more but I needed my car running again the next day.

 

Id recommend using how water when mixing with the flushing chemical, let it sit for about a half hour,and swoosh it around really good, repeat, repeat, then flush it with the hose after its cooled down of course

 

Use lots of water (garden hose on high) and turn it a lot; worked for me.

 

I flushed mine in the car. Drained it and then refilled with 50% distilled water/50% white vinegar. Ran it for a while, even drove it while it was at operating temperature so the thermostat stayed open and it circulated through the block. Then took it to my mechanic and had them do a radiator flush- boy were they PISSED! It looked like the entire cooling system had been filled with rancid Coca Cola! Brown foam and filth just kept draining out until there was nothing but pure spring water running out of the drain! I could not believe how much crap it took out. So fill the radiator with the mixture, cap it off and let it sit, turning it every couple of hours. Let it sit over night at least. That should resolve all the scale built up, not damage it like some commercial cleaners I would think, and it is biodegradeable!