I must respectfully disagree with you here. The only way to get the fins clean is to remove the radiator from the vehicle and spend about 90 minutes with foaming cleanser and compressed air to get MOST of the crap out from in between the fins. After you remove the radiator, and you believe it to be clean, just hold it up to the sun. You will see the internal fins thorougly clogged with very fine debris. The outside of the fins look perfectly clean.

Even after 90 minutes work on the SD, it still was not fully clean. I need to find a better chemical other than the Dow Foaming Bathroom Cleaner that I had around. There are special cleaning agents for condensers that would do a much better job.

You absolutely cannot clean the radiator fins properly with the radiator in the vehicle. I did not fully clean it with the radiator out of the vehicle