C2 Cooling System Crud

[Dave Kitch (33108)]

Several months ago I started my 66 small block while off the frame and ran it with once through tap water from a hose. I didn't drain the block following the run. Therefore there must have been several quarts of water left in it. I dropped the body, filled the cooling system with tap water to check for leaks and started it. There's a new radiator in the car and the heater core was flushed and pressure tested. Engine runs good and cool. However, I drained the radiator and noticed that the coolant was a muddy rust brown and smelled yucky. I assume that this is the engine cast rust residue.

I'm thinking of dropping the boomerang brackets and pulling the block plugs, draining the radiator and adding a cooling system flush. Draining again flushing as required, than adding anti freeze. Will an engine flush harm the new radiator or the old heater core? Any comments on a procedure?

Thanks,
Dave Kitch
33108

[Gary Schisler (21316)]

Re: C2 Cooling System Crud

Dave, since you just had tap water in there, the usual and normal chemical reaction took place: H20 + Fe = Fe2O3. I would drain the block (using the hex block drains) and flush several times with straight tap water. Drain again and add antifreeze, which contains anti-rust agents, of course, and add distilled water.

Gary

[Duke Williams (22045)]

Re: C2 Cooling System Crud

I agree. Drain the block, then flush the system with tap water until it is squeaky clean. You can do this cold/enngine not running by disconnecting the heater inlet hose from the inlet manifold nipple and flushing both the engine and heater circuit. I'd also suggest a hot flush or two by filling with water and then running the engine until the thermostat is open for at least a few minutes, then drain, let the engine cool and repeat as necessary until the effluent is clean. Don't use any commerical "flush" products.

Fill the system with at least a 50 percent mix of Zerex G-05 and distilled water and change the antifreeze every two years, regardless of mileage.

Duke

[Jim Baxter]

Re: C2 Cooling System Crud

Where can you get Zerex G-05 I went to O'reilys, autozone and wal mart with no luck?

[Gary Schisler (21316)]

Re: C2 Cooling System Crud

Pep Boys, Advance Auto. "Let your fingers do the walking"?

Gary

[Duke Williams (22045)]

Re: C2 Cooling System Crud

I was at my local Pep Boys yesterday (So Cal) and they had it - $9.99/gal. Antifreeze prices are going up along with with gas!

Duke

[Dick Whittington (8804)]

Re: C2 Cooling System Crud

I just purchased a case from a local auto parts jobber. $49.75. Ain't cheap back here in thar hill either.

[Mike McKenzie (32993)]

Dexcool for C2

Duke, You are not reconding Dexcool for a C2 with aluminum rads. Is that because of the heater core. If so will it do any damage to the core, if left in for a couple years. Thanks Mike

[Duke Williams (22045)]

Re: Dexcool for C2

Yes, I've backed away from my Dexcool recommendation. Recent credible articles I have come across indicate that the industry consensus is that Zerex G-05 or an equivalent HOAT inhibitor package is best for older cars that were originally equipped with IAT (green) antifreeze.

There is some concern that Dexcool will not protect provide adequate protection to some solders in conventional brass radiators and heater cores.

I will probably switch a couple of my cars that now have Dexcool to G-05 at the next scheduled change. and I have had no solder joint problems with Dexcool, which I've been using it since 1996.

Right now I'm leaning about 51/49 toward G-05 for vintage Corvettes because nearly all have soldered brass heater cores, but rather than running out to the garage and doing it today, I am waiting for the next normally scheduled two-year change point.

For those cars with aluminum radiators and heater delete, I would still recommend Dexcool, but if you have either a (brass) heater core or a brass radiator G-05 might be a better answer.

Duke