One more thing to try and it can help clean both the radiator and the AC coils out front. Pull the radiator to clean it since it is covered up by the AC Coils (if you have them). But much better than just shooting some water up in there.

Mix up some cleaning solution for cleaning your home AC coils. Do not use a too strong mix, 5 to 1 is what the bottle I have recommends for a mild solution. So that is about as strong as you want to get it, use 6 to 1 for cars just to be safe. This is a very agressive acid and stronger is not better. Drip a small single drop on the concrete and watch what happens and you will see why you have to be careful and follow directions. This will take the hide off of things it does not belong on so read the instructions, be careful, and use an really good plastic spray bottle. Wearing a pair of good chemical resistant gloves and Eye protection (before you open the bottle to do the mix) you can remove the grill and gently spray the coils (I wear a mask also). Be precise and a gentle spray, do not get carried away. Start at the top and work your way down the coils. It may foam up a little, that is the reaction with the oxidation. Let it sit for a minute or so and then flush well with water, low gentle pressure at first starting at the top of the coils to stop the reaction of the acid and to remove the junk the acid removed. You can really get after it after the gentle flush is done, but do not get carried away with something like a pressure sprayer. Manly yes, but also stupid watched a idiot ruin a radiator, fun to watch, expensive to do. Suggest not doing this on your manicured lawn by the way. Can lead to little dead spots.

But you can see the shine when you get done.

Good Luck,

PT

I was going to tell him the same thing. I bet his fins are full of Florida bugs.

I hose the radiator everytime I do the Timing Belt and have the Fan and shroud off te engine
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

The super nice copper radiator original to the car blew a hole in the side tank at about 115k. This was about three months ago. I have already done the coolant flush 50/50, the radiator is a newer junkyard blackstone unit from a 94 (I believe) which I cleaned out thoroughly also giving me the chance to get at the engine side of the condensor as well. I spray the condensor and rad fins every time I wash the car. The thermostat works ok. [The thermostat btw fails in the "open" position.] But I might just pull it out and boil it to see what happens.I doubt that's the problem its a whaler 87 degree jobby. Could my water pump be the culprit? It was last replaced at 100k she now has 220k on her. The viscous fanclutch works because I can hear it engaging when under way after idle - sounds like a school bus when the temp goes up.