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Hi,

Has anyone ever used CLR to flush their Radiator? Did it work well?

What would the best way to flush my rad?

Thanks!

probably the best way would be to pull it out and take it to a Rad shop and have them clean it. I did that with mine and it turned out great. i also had some old solder repairs on the Rad tank and they fixed all that up also

All those fancy bottled elixers are just hog wash. There are only two reliable flushing methods. Pressure reverse and caustic tank soaking.
With the air adapter for your water hose you can reverse flush the radiator and the block yourself right in the driveway. If it is stopped up so bad the air pushing the water backwards through it caN'T UNBLOCK IT THEN DON'T WASTE ANY MORE TIME ON IT. tAKE TO THE RADIATOR SHOP FOR THE HOT CAUSTIC TANK SOAK.

Thanks for the info!

I am going to remove my radiator tonight and back flush it. I am also making an adaptor to go where my thermostat goes to allow my water hose to hook up to back flush the block.

I just picked up a 160 deg thermostat to replace the old one. Also a new radiator cap. 4 lbs rating. Let’s hope this fixes my problem.

Well I changed the thermostat, back flushed the block and rad. Even removed the rad and back flushed it. Lots of crud washed out. I put every thing back. Started the jeep and let it fast idle to warm up, and after about 10 mins of running, it overflowed and empty half of the new coolant out, I added more and then took it for a drive and the temp gauge dose not go over 120 deg. It only seams to over flow when the thermostat opens up. Could the rad still be blocked? Could it be the head gasket?

Any ideas?

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Bruce,
Have you made any progress on this?
A radiator shop can clean and should FLOW TEST our radiator.
The backflush can clean out the block.
Check your thermostat.
Be sure your hoses are not kinking.
Your radiator shop should also test your radiator cap.

Can you get a cooling system pressure tester? You should be able to put a few pounds on the system and have it hold.

Are you saying you have done all of these checks and it is puking a larger than normal amount of coolant out of the radiator overflow hose?

If you let it heat up with the cap off do you see a lot of bubbles in the top tank of the radiator especially when you rev the engine? Do you see any oil or gray cloudyness in the coolant?
A head gasket leak is something to check as part of your cooling system health check and you may find the lead during the pressure test.
Another way I have confirmed a head gasket leak (crude but it worked) is to tightly tape a baggie over the filler of the radiator and plug the overflow. When you run the engine does the baggie fill? This may be showing that some gasses are getting into the cooling system.

Let us know how you are doing.

Tom

Yes the radiator could still be blocked. Plug the lower outlet on the radiator and fill it up with water and then unplug the lower outlet. If all the water you put in flows out the bottom then the radiator is clear. Use those empty coolant jugs to measure your water in and water out.