I dunno, I like the 'better driving through chemistry' idea, but I think
I'd rather take the thing apart, have the rad boiled, and flush everything
else with a hose first, then try a phos. acid spray in the block only.
then rinse. a lot. since it's that old anyhow, replace all the hoses. a
low enough concentration acid won't hurt the iron, but don't leave it there
too long. several commercial kits are designed to clean rust from gas
tanks--they use phos. acid, but most tanks are steel. won't be a big
difference, but the iron would (in theory) degrade faster.
I think maybe the better thing would be to try a commercial kit for
derusting/descaling your cooling system. do this _before_ you have your
rad boiled. the kit would probably be cheaper than getting the acid,
anyway.
and, once you clean the system thoroughly, you might find that the rust was
plugging some holes you didn't know you had. another reason to take it
apart and give it a good, thorough cleaning.
scott
-----Original Message-----
From: david [SMTP:engstrom@tstonramp.com]
Sent: Wednesday, August 04, 1999 12:15 AM
To: spitfires@autox.team.net
Subject: cooling system
Hello to everyone. Anyone have any thoughts or experience with
derusting a spit cooling system with phosphoric acid? I was pondering
filling my system with 0.1 molar phosphoric acid and running it for
maybe 20 minutes and then letting it sit overnight, then another 20
minute run, then 2 or 3 flushes to dilute the acid/rust out. I don't
think the acid would do any damage but I'm not sure. My system has a lot
of rust in it. I ran the engine at 2k rpm for a half hour and the temp
gauge equilibrated at the center of its range, also the engine never
felt/showed any symptoms of excessive heat. But, of course, I'm
concerned about local hot spots in the engine due to local coolant
blockage caused by rust deposits. This is a mk2 that sat for 10 years,
and has probably never had the cooling system cleaned. Also, anyone know
where can I obtain phosphoric acid?
Thanks, David
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