Swimming Pool Acid in Radiator

[Alex Gilmour]

All, I read a while back in one of the muscle car magazines about using common pool acid as a cleaner for the radiator (after it is out of the car, of course). I wanted to know if anyone has used this method (fill and agitate) to clean their radiator. I have the original radiator in my '66 and would hate to do anything to trash it.

Thanks, Alex

'66 A/C Coupe

[Joe L.]

Re: Swimming Pool Acid in Radiator

Alex----

"Swimming pool acid" is usually muriatic acid, a somewhat dilute, commercial grade of hydrochloric acid. I have no doubt that the acid will clean the radiator but copper and brass are readily attacked by hydrochloric acid. I wouldn't recommend using it unless you know exactly how to do it. Your best bet is a commercial radiator cleaning solution or taking it to a radiator shop that is experienced at chemical cleaning of radiators.

[Gary Schisler]

Re: Swimming Pool Acid in Radiator

I also have a 66 with an original (and partially plugged) aluminum radiator. i would be real hesistant to try this without trying it on an old aluminum pan or something along those lines. I have talked at great length with a radiator shop owner, who is also an original and still current owner of a 63. This gentleman insists that NOTHING that we can put into an aluminum radiator will clean out the residue that has condensed out of solution over the years, without damaging and, perhaps even destroying, the aluminum radiator. In addition, I have talked with two corporate chemists and they pretty much agree that the acidic solutions will attack the aluminum. To date, I have not done this even though my car overheats at highway speed in the summer. Any comments here?

Do any of you fellow enthusiast have experience here? I am very close to buying a new, repro radiator for my car. The external part of my original radiator is perfect, the guts of it are another story.

[Joe L.]

Re: Swimming Pool Acid in Radiator

Gary----

The comments that I made previously for Alex' brass radiator would go double for an aluminum radiator. Aluminum is a much more highly reactive metal than brass. Hydrochloric or any other strong acid will attack and destroy it quickly, especially considering the thin metal involved. Also, aluminum is what's called an amphoteric metal. That means that it dissolves in both acidic and basic solutions. Consequently, if one were to use a strong caustic cleaning solution, that would damage the radiator, too. That's also why you can't put aluminum parts into an old-fashioned, machine shop "hot tank". Hot tanks contain a heated, strong caustic solution. This works wonders on steel or cast iron, since they are impervious to strong bases. Put aluminum parts in there, though, and they'll be gone in short order. In fact, leave them in there long enough and they "disappear" altogether.

There are commercial cleaning solutions available for aluminum radiators which are safe for use in them. The problem is, they're usually not nearly "aggressive" enough to deal with major clogging.

[Jack H.]

Re: Swimming Pool Acid in Radiator

Experience here in Denver with 'cleaning' original aluminum radiators is not good, sorry to report. Our chapter technical advisor runs a shop and over the last 15 years, his experience is:

(1) Start with a non-leaker or very minor leaking original. (2) Pick any rad shop you've confidence in. (3) Consign radiator for clean/repair. (4) If it comes back 'cleaned' it's a matter of time before it

springs pin holes.... (5) Typically, get the "tried but can't be saved" response.

Brass babies are another matter altogether!

[Greg Vaka]

Re: 66 Vibration..still got it!

Was your pilot bushing replaced at the time your clutch was replaced? Do you have any clutch chatter? A oblong worn bushing can cause misalignment of the input shaft to the trans and cause an imbalance of the disc and shaft under load only to go away when the clutch is depressed allowing the input shaft and disc to center. I had a 1982 with the same problem that went away with a new pilot bushing. Actually the bushing was almost completely worn away.

[John H.]

Another Good Argument.......

For using the needle roller bearing instead of the cheapo bronze bushing; once you go to all the trouble of clutch replacement, pull and pitch the bushing and replace it with the ($12.00) bearing - they last forever.