My 94 regal's heat is not the best, takes forever to get warm and is only luke warm. I overheard a tech at futureshop today talking to another salesrep saying he got his truck heater fixed today, they flushed his clogged heater core with CLR and it works like new again.

Anyone ever try this? Would the CLR hurt anything? IE: removing any rust or filling it shouldnt?

Thanks Jason

never heard of that before. At work I just disconnect the hoses to the heater core, connect the hose to one side and turn on the water. Do that both wasy and it blows all the crap right out. Heat always works great after that. Did that to 2 cars this week.

Thanks, will give that a try

CLR stands for Calcium Lime Remover. Depends what the core is clogged with. If it's lime or calcium (same thing maybe) it will probably do the trick, coupled with a back flush as suggested above. I usually have to do my old jeep's heater core every winter. The 1st couple of years, I mixed up some eng cooling system flush/hot water and poured it in thru a heater hose and funnel and let it sit overnight. It worked good enough for west Texas winters. The 3rd yr, I used clr. When I back flushed it, all kinds of crap came out-mostly chunks of rust. Here lately, I only backflush it---it helps, but not as well as using a solvent of some kind. Make sure you backflush it with both hoses disconnected from the heater core, or all that crap will just end up back in the cooling system or on the inlet side of the radiator core. I went ahead and installed one of those 'tees' in the outlett hose of the core. Now, I only disconnect the inlet hose, hook up the garden hose to the tee, and pinch off the downstream side of the outlet hose, to keep the garden hose water from going into the engine instead of the heater core.

[This message has been edited by maryjane (edited 01-10-2004).]

Read the label.... CLR and similar products are ACID. They may eat out the blockage but they will also eat the rest of the metals in the system.

Acid flushes were used years ago when radiators were copper/brass. They stopped making these products because of Aluminum radiators. You'd be amazed how fast small amounts of acid and some other chemicals can eat aluminum.

The only way I would even think about using acid in a heater core is if the heater core was out of the car or otherwise disconnected from the rest of the system.

Odds are... if the heater is blocked so is a significant portion of the radiator. You should replace the heater core as even if you get it cleaned out it will probably start leaking soon if it isn't already. You should also have the radiator checked and replace it if the thing shows blockage. While it is possible to clean them with pro tools... you will get much better cooling and longer life from a new one.

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Thanks,

The rad was replaced last winter and so was the thermostat. I dread the thought of trying to change the heater core.. I will unhook it and flush it with just water to see if it gets any gunk out of it.

I was sorta weary about the CLR in a newer vehicle.

Just to put things in perspective, my old jeep (that's never had either the oil pan or valve cover off), just rolled the odometer yesterday-to 280,000 miles. I may not be doing everything by the book, but I guess I'm gettin by.

Don,

When you used it, did you dillute it any?

I think I will try by just flushing it first to see if it helps any.

Last ditch effort, I will run a dilluted mixture just as a test (once I have a new core in my garage ready to install)

[This message has been edited by isthiswhereiputausername? (edited 01-10-2004).]

No, I didn't but I suspect it already is diluted. It doesn't burn your skin at all, & I've used it often here in San Angelo. The CLR I used is CLR (as seen on TV) Bathroom & Kitchen Cleaner. I've got the bottle in front of me. Like I said-it depends what is clogging the core. If it's not lime type deposits, it may not do a dang thing. I used it because I didnt have any eng & rad flush with me at the time, and my jeep requires A/C evaporator removal to get to the heater core. That means losing all my hi$$ R-12. I suggest trying a straight water backflush first, if you have any doubts about using the CLR. Mine is an older vehicle(84 Cherokee), and they did use a copper core back then. in other words, use your own judgement.

quote Originally posted by maryjane: No, I didn't but I suspect it already is diluted. It doesn't burn your skin at all, & I've used it often here in San Angelo. The CLR I used is CLR (as seen on TV) Bathroom & Kitchen Cleaner. I've got the bottle in front of me. Like I said-it depends what is clogging the core. If it's not lime type deposits, it may not do a dang thing. I used it because I didnt have any eng & rad flush with me at the time, and my jeep requires A/C evaporator removal to get to the heater core. That means losing all my hi$$ R-12. I suggest trying a straight water backflush first, if you have any doubts about using the CLR. Mine is an older vehicle(84 Cherokee), and they did use a copper core back then. in other words, use your own judgement.

Thanks Don,

I will try the water flush first thenthe next step would be replacing, but before I replace it, I might as well give the CLR a try.. if it works - great.. if it dont, its coming out anyways