CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

John's GMC Radiator

I was just listening Saturday Aug-27th, when Tom and Ray talked with John in Columbus, Ohio, who had mineral deposits in his radiator on a diesel GMC. Evidently the Ohio Water is very “hard” and mineral laden, which caused it to leave hard deposits in his radiator… coating the insides… clogging up many of the little passeges… blocking flow of coolant water+antifreeze… and causing his nice GMC (which he loves) to overheat. A new radiator is over $500. There was some discussion of distilled water being Hungry… but I’m going to press Tom’s “BoOoOgUS” button on that one. (he can still feel free to talk to his Chem-Professor for more detail) Part of John’s problem is… He ALSO has those same mineral deposits EVERYWHERE else in his cooling sysetm: including the engine and his heater-core, so this keeps his engine a bit warmer, and in winter keeps his passengers colder… then even after replacing that $500 radiator, and using distilled water with his antifreeze -all those mineral deposits are still polluting his nice distilled water in the coolant system.

Good News; I think I’ve got a great solution for you (and much cheaper). When Tom+Ray were thinking about talking to a chemist. (as with most long term car+owner relationships: chemistry is involved) It might have even been more effective to talk with an Ohio Plumber, about those mineral deposits. Leave that OLD radiator in the van, drain out the coolant/antifreeze you have now (with the engine cold)… Flush cooling system with “plain ol garden hose water” and then add a quart of “CLR” to the radiator, instead of antifreeze, and drive it regularly for a week. This stuff will chemically disolve the mineral deposits while you drive, and get them out of the radiator, engine, heater core, and everything else. At the end of a week, your system should be “sparkly clean” on the inside, and it only cost you $30 instead of $500+ for the fix. NOW that you have a happy GMC, go ahead and drain out the water+CLR+disolved minerals… flush the system again, add that distilled water you were thinking about, along with regular anti-freeze, and drive happy for the next five years – smiling to yourself that somebody posted on Car-Talk to save you $500 bucks, and you didn’t even have to pull the radiator!

Side Notes:

( Link to the call) http://stream.publicbroadcasting.net/production/mp3/cartalk/local-cartalk-983595.mp3
( Link to CLR. You can buy it lots of places from Lowes to Wally-World ) http://www.jelmar.com/CLRbasic.htm

(1) It’s currently August and plenty warm, so you can drive two weeks FINE in Ohio, with no anti-freeze… If you are reading this wonderfull adivce in January (when it’s 20 BELOW freezing) don’t drive without antifreeze, and crack your engine- just drain out a quart of water & add the CLR, drive a week… flush the system, and add new coolant.

(2) I know that you guys don’t really “push/promote” specific brand products… and I’m not trying to sell anything… but this particular CLR stuff does seem to work, and it doesn’t eat plastic+rubber+cause other problems… and it seems to be OK with boiling range coolant temperatures in the engine. I don’t work for the CLR guys, or sell their bottles’ of chem-cleaner, so this is not that kind of a “plug” posting.

(3) If you car/van has Other weak points in the radiator, or cooling system… it may be that these minerral deposits are the only thing sealing up your radiator, and keeping it from leaking. When you “clean out” the system real good, you should watch for a few weeks to see if other small leaks pop up, and take care of those. For instance: If you had a flaky water pump with 120,000 miles on it, then cleaning out the Mineral deposits can cause it to leak. That thing neaded replacement anyway- you just didn’t know it yet. Beware the temptation to take that nice clean cooling system and then add some kind of radiator “stop leak” three days later. That can also “gum up the works” inside.

(4) After this works out great - put one cup of CLR in your other cars, and just leave it there, to help prevent this same problem from happening with those other radiators.

(5) I’ve taken time to go online and write a long/detailed post, and save you $500 bucks… I hope YOU take the time to come back in a few weeks, and let Tom+Ray+Me know how things worked out… so 800 other people in Columbus can read it, and fix their radiator problems cheap… OR so you can tell the world that MY answer was just as BoOoOoGuSss at the one Tom+Ray gave, and I have NO idea what I’m talking about. Either way, I hope your GMC is happily cruising down the highway for another 80,000 miles, with it’s radiator+heater-core in good shape.

@Atlanta_Joe thank u for the advice. A friend of mine told me about this also. Im doing it right this minute… Hopefully it works!! Ill let y’all know in a few days whether or not it helped my Mitsubishi. Happy New Year all