Radiator Replacement Question--two parts!

[GAK the Anorak]

I'm replacing the radiator on my '71, 351c, v8. Car has been sitting for 25 years with fluids in it, including coolant.

1. I removed the first drain cap on the engine block but cannot loosen the second one--driver's side. Is it necessary to open and drain the second reservoir prior to replacing the radiator and refilling the system?
2. The fan appears in good shape...what are the signs that I should replace that while I'm at it.

 

[basstrix]

If it's a flex fan, inspect the flexible blades for cracks.

Those block drains can be a bear to get out. You may have to resort to using a torch and wax to get them out. If you don't remove the one plug, you won't be able to drain that side of the engine. Not the end of the world, but preferable to have that ability.

You can expect that the block is going to have A LOT of rust in it and you'll probably need a new thermostat. You'll want to flush it several times with just water, until you can get it to run clean. EvapoRust makes a product that dissolves the rust and pulls it into solution. That would be a good step to add after several flushes with water. Once you're done with water flushing, drain completely (that's where it's beneficial to have both plugs out of the block) and then add your 50/50 mix of antifreeze and water. If you're going with an aluminum radiator, make sure the coolant is recommended for aluminum.

I suggest you bypass the heater core circuit and flush that separate.

I suggest an inline filter screen that goes into the upper hose. That will allow you to see the coolant and also see chunks of crap coming through the system....and keep it out of your new radiator. They are kindof expensive, though, and I'm not convinced they're all that durable. I have one...I installed it while doing the flush, then removed it.

Don't be surprised if you uncover additional problems...leaking core plugs, head gaskets can take a beating, front cover plates can rust through....I've seen a mostly-dissolved thermostat.

Last, but not least, I HIGLY recommend the No Spill funnel kit. They sell them on amazon and harbor freight....makes filling and burping the cooling system a breeze. They are not cheap, but IMO, worth every penny.

 

[Aus73Mach1]

Pull the radiator hoses off as well. If they have the internal wire coils, check they are in one piece. If not those bits of wire are probably inside the block.

 

[GAK the Anorak]

Hugely helpful. Thank you.