I change coolant quite often also.

Per the CLR, this has been debated on other forums I am on and the way I see it, the odds of eating the aluminum in 20 minutes soaking the mineral dpeosits is nil. Plus if it does leak, it is probably because the mineral deposits built up inside are the only things preventing the leak.

 

you are welcome to take the risks yourself, but i wouldnt be recommending it to others with that possibility

 

I wouldn't use it!

 

Today I filled the heater core I took out. Filled it with CLR and set it on the porch to soak in the sun. Checked on in in 10.. then 15 min.. .. CLR got cloudy but not too much. Came back 2 hrs later (family time!) poured out the CLR and LOTS of RUSTY sludge and little flakes of rusty colored calcium buildup came out.

Did another rinse on it with CLR another 2 hrs.. more flakes came out than anything else. Thing still weighs more than the replacement I put in my Durango.

No leaks but then again its not under pressure. I don't trust to run it in my vehicle again. Especially since I have a new waterpump/radiator/heater core already in the truck! lol

I was expecting the CLR to eat through the heater core after 4 hours but surprisingly it didn't.


Question: Has anyone tried the wood bleach/dishwater detergent rinse before? I have thought about trying to rinse out my block since so much rusty sludge came out of the heatercore, but I don't want to damage anything. I fear ruining the freezeplugs or my new radiator/waterpump/ect ect...

 

you can disconnect the radiator while you you do the rinse if you want to, just makes it less straightforward than if you leave it on,

 

Never tried it.


Now if you use Distilled water and coolant or Prestone 50/50 then the minerals should be removed so the deposits are hindered form being deposited in the first place.

 

Its the rusty goop I want to flush out of the block right now. Supposedly the best way is to remove the block drain plugs but I bet they are frozen in place with the truck being a 98! I really don't want to remove the engine to drill one out and repair the threads!


BTW. The CLR in the old heater core did NOT eat through the aluminum yet! I forgot I filled it again and when i checked it this morning the CLR poured out slightly cloudy but none had leaked out!

I am very surprised it did not eat holes through the heater core!

 

Don't mess with the drains on the heads but I would think you should be able to get the very rear block drain (#4 and #8) out.

 

I doubt CLR is that caustic where it would eat thru. That was my point.

I just disconneceted the two heater core hoses when I did my shadow.
Blew some compressed air to clean out the old coolant. Then mixed CLR and distilled water 50/50 and let it sit 20 minutes. Then poured more distilled water in one end and drained the other hose into a bucket to see what came out. As I recall it looked cloudy wiht crud floating in it. Heater core performance drasitcally improved, to this day I get good heat, even when it gets -20 below up here in maine.

Then I hooked up garden hose to flush both hoses. This is done all the time on Turbo-Mopar.com by many to salvage poor heater cores. Mine at the time was about 18 yrs old and had 240K on it.
Note I owned the car since 1992 and put over 200K miles it during that time. I generally change the coolant every 25K miles or so.

If you want to perform a test why not put a chunk of aluminum in a cup of CLR and see if it eats it away.