aluminum radiator care

[Alex Fiato]

As a newbie, I am risking this question after having waded through some of the posts in the archives. I have never had an overheating problem with my '66 HE. Nor have I changed the anti-freeze in the last 10 or so years. I would like to know the gospel on flushing the radiator, and possibly the heater core, and the best coolant for the re-fill. The car has 67K miles and gets driven about 500 miles/yr. I have heard and read stories about turning a tight rad into a leaker by flushing with good intentions. Flushing the core and the engine is simple enough but the AL radiator puts the wrinkle in the equation.
I feel it's time to at least change the coolant but would appreciate some input from those in the know before I do. Thanks in advance for the help.

[Duke W.]

Re: aluminum radiator care

There is no substitute for good cooling system maintenance and no cheap recovery from poor cooling system maintenance. If you neglect it the radiator tubes will clog up, the engine will run hot, and that's it. If it's an aluminum radiator, your only choice is to replace it. The aluminum radiators are not reparable. Pay me now or pay me later as the saying goes. Brass radiators can usually be repaired if there are no tube leaks.

Commercial flushing products are basically worthless. Just thoroughly drain the old coolant including removing the block drain plugs and then flush the system with water by disconnecting the heater inlet hose from the inlet manifold and flushing both the heater core circuit and engine. It's also worth while to do a "hot flush" or two. Fill the system with water, run the engine to operating temperature for five to ten minutes, then drain.

Use Zerex G-05 antifreeze mixed 50/50 with distilled water. It's HOAT formulation will minimize deposit buildup while protecting the heater core solder. Go to the Valvoline web site to learn about G-05 and the various types of antefreeze - IAT, OAT, and HOAT.

Lack of coolant changes and use of the old "green" (IAT) antifreeze causes deposits to build up in the radiator tubes. There is no way to remove them. The radiator is not reparable. Best life from aluminum radiators is had by changing the coolant at the manufacturers recommended time interval, REGARDLESS OF MILEAGE. It's either or, whichever comes first, so two years is the deal even if the car is barely driven.

Also make sure the rubber radiator mounts are in good shape and check that the radiator is electrically isolated from the chassis. This will minimize the rate of galvanic corrosion.

Duke

[Alex Fiato]

Re: aluminum radiator care

Thanks for that. I'll get on it.

[Gary Bishop]

Re: aluminum radiator care

I want to change my antifreeze in my `62 myself, but what to do with the gallons of original and flushing liquid. When I asked at a couple of local garages about flushing they both said "DO NOT power flush". Just drain and refill.

[Jim T.]

Re: aluminum radiator care

Gary in changing your coolant and what to do with removed coolant and flush water. Not knowing what your state laws are, you may not be able to do this, I pour it into the kitchen sink drain which of course travels to the wastewater treatment plant. Twice a year hazardous waste materials are collected for free desposal where I live. I would save my old coolant for this disposal if I had not witnessed old coolant going into the sewer system at local vehicle repair facilities. You might check with you local WAL-MART, they may take it. This is where I dispose the oil from my vehicles.

[Timothy B.]

Re: aluminum radiator care

Duke,

Can you explain the differences between OAT (dexcool) and HOAT (G05) antifreeze, seems they both use acid technology? I installed dexcool in my 1963 vette new radiator with no problems but it seems now that the consensus is to change. My cooling system is tight and the dexcool has been in the car for over a year and still looks new. Thanks, Timothy Barbieri

[Duke W.]

Re: aluminum radiator care

Proper antifreeze disposal varies by location. In Redondo Beach, it's okay for DIYers to pour old antifreeze and glycol-based brake fluid down sanitary drains, but it's not okay for commercial shops to do so, so check with your local haz mat specialists. The fire department might be a good place to start.

You should not pour old antifreeze or brake fluid into septic tank systems!

Duke

[Duke W.]

Re: aluminum radiator care

Go to: http://www.valvoline.com/pages/produ...asp?product=10

Read the information on G-05 then download the pdf file on "antifreeze color".

In the past I have been a proponent of OAT Dexcool for vintage Corvettes, but I am now leaning 51/49 towards HOAT products like Zerex G-05.

I don't think you need to change the Dexool, now, but at your next scheduled change you should consider switching to a HOAT like Zerex G-05.

The primary concern with Dexcool is whether or not it provides sufficient protection for solder joints like heater cores and conventional brass radiators.
Virtually all new cars including GM use aluminum radiators, but I'm not sure what materials are in GM's modern heater cores.

Duke