Just did this job this week. I have not tried this specific product, Coil Cleen by Landmark Wax. I note that it is made to be used on bare metal coils (condensers, etc) and in our trucks, the radiator is painted and the A/C Condenser is also painted. I have no idea if this is a problem with Coil Cleen - I wouldn't think so. What I used was Turtle Wax Bug & Tar Remover after reading a recommendation on another post, and a degreaser by Auto Magic.
I started by moving the trans cooler, a/c condenser out of the way as much as possible, then separating the intercooler and radiator at the top by a coupld of inches. Then used 150 PSI compressed air with an angled blowgun and a short nozzle to clean them out from the backside. This makes a very concentrated but narrow blow pattern. The a/c condenser held lots and lots of pieces of grit, sand, and the more I used the air the more the grit came flying out. You couldn't see the grit coming out, but when you held your hand in front of the condenser, you could feel the sting of the grit that was being removed. Took probably 10 minutes to rid the condenser of the grit.
Then soaked each piece in the stack with the Tar & Bug Remover, let it stand for 10-15 mins, then rinsed. I tried using my pressure washer with the widest nozzle but found that just using the garden hose with my finger worked even better. After that, I sprayed the stack down again this time with a degreaser, waited 10 minutes, and rinsed again. When finished, the stack definitely looked cleaner, especially the a/c condenser. I bent a few fins using the pressure washer, but not many.
My stack wasn't real dirty and I didn't really think it was. But I experienced some cooling problems this summer and want to be SURE the problem wasn't the cooling stack before I started on other, more expensive and time consuming solutions for the cooling problems.
