I flushed my '72 Scamp block two months ago with a 60 psi garden hose and 100 psi air blasts before replacing the radiator. I just found that the new rad was clogged with rust chunks. Since the garden hose pressure obviously wasn't enough I plan to use more water pressure.

I flushed with the rad out, freeze plugs in and water pump in. No I didn't pull the drain plug as I was looking for a hex bolt plug and now know its a allen key plug that was hidden under the engine crud. I will pull the drain plug this time and the water pump to get as much gunk out. Can't get to the freeze plugs as the motor is in the car with the exhaust manifold on and I don;t want to mess up my brand new Remflex gasket.

The question is how much water pressure. I have access to 120 to 180 psi and can still add the 100 psi air blasts. Will this blow out freeze plugs or gaskets?

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE

I bet you will get a ton of junk out when you pull the side plug. It might even be plugged up. I'm not sure about the water pressure, I just used a garden hose with a nozzle. I had the same issue with my 67 Dart. Flush the heater core while your at it. I also installed a petcock drain in place of the side plug.

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I worry about the heater core so by-pass that, before doing the high psi flush-out.
DD

Time for a coolant filter. You probably knocked a bunch of stuff loose.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

I tried the ol' ladies nylon. It does catch a lot of junk. Not very user friendly, though!

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63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.

I did cut the heater core out by removing the water pump. Good call. I flushed that with just one garden hose. I did dangle a knee high in the upper rad hose to see if anything ales moves through. I had to drill out and easy out the drain plug. I installed a mechanical temp gauge back where the drain plug was. That was a mistake as the water is 30 plus degrees cooler there. So a plug will be going back in. I did get enough crud to fill a soup can about 2 inches. Thanks for the help all. SS

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE