I am getting a new shortblock and a new radiator so they are fine. But I would like some ideas on how to flush my heater core before the engine goes back in. What would be the best way to do this so all of the old coolant and water is fully evaporated before installation of my new shortblock.

Thanks.

 

You could rig up a water pump & some Prestone coolant flush. Short of removing it, that's all I could think of...

 

I was thinking of trying to just flush it out with water and some degreaser and let it air out. Once all the coolant is out, then the water should evaporate, right?

 

you could open all heater valves and blow air thru it ,low pressure,
then put a hose on top heater hose ,slowly pour about cup full NPG till it runs out bottom hose.

put it together and run it leave little room for expansion,water will evaporate if any,

NPG Evans seems to expand a lot, so i leave mine down a little,
and no pressure cap, make sure overflow tank is empty, so you can see how much it expands. it equalizes after a time.

i been using it for 10yrs, same fluid, no signs of corrosion, good pump lube, 100F--down to 30F. turns to a clear brown color

 

I would contact Evans for a good method but, according to the "Street Rotary" book by Mark Warne "Evans NPG cannot operate in the presecense of water" the book says Pineapple racing recommend flushing with water once, then flushing with pure 100% propylene glycol two more times and driving the car around enough during those flushes to make sure all the flush coolant circulates entirely. It's pricey but so is Evans and you only want to do it once. The key is get all the water out.

 

What if I just flush out the core with propylene glycol a few times? I haven't bought the Evans yet and my engine won't be going in for about a month. So anything I can do to help prep it. I don't want to have to put the whole thing together and then do that cycle. It would be nice to just drop the Evans in right away and be good to go.

 

Fill heater core with Sierra coolant (no water added); vacuum with a wet/dry vacuum.

 

hmm, that sounds like an idea. if I did that a few times I bet it would work!

 

If your engine is not in the car that it should be empty so check that off the list. Flush everything else out really well. Maybe you could just leave the wet/dry connected and sucking for a long period of time...like a reverse hand dryer or something. The book was specific about flushing with 100% anti-freeze though. Lots of emphasis placed on getting all the water out.

 

Ya, the engine is new as will be the radiator. The only thing with coolant remnant though is the hoses to the core and the core inself.

 

If the hoses are original you might as well replace them too.

 

Agreed.

 

Evans makes a flush called Prep Fluid. They recommend draining the system of coolant, filling with Prep Fluid half the normal capacity, run engine to warm, and then drain. Bought some today, coincidentally

 

I started in the same place in 2003. Blew air threw the heater core and ran Sierra for 500 miles then switched to Evans and did first oil change on fresh motor.

Jack

 

Its not going to kill you if you still have a few ounces of water in your block. I use Evans and in a pinch and added about 16 oz of standard radiator fluid. Im going to drain it all out again, but you'll be fine. Take the plug out of the block, put the block on an engine stand, and flip it. Other then that I WOULD NOT put any engine cleaner or any other fluid in.