Spent a couple hours this evening removing my front bumper cover and cleaning out the radiators in my 99 996. I followed the instructions in this video - http://www.youtube.com/watch?v=Um-h2aUJHY4. It was very helpful.

I couldn't believe how much debris was in there, especially the gunk caught between the cores. I highly recommend doing this if you haven't already.

 

Thanks for the post. I'll have to clean mine now.

 

Do you just pressure wash the radiators? With soap? Just water?

 

No, I just vacuumed them out, which seemed to do the trick pretty well. The radiator surfaces were in pretty good shape once all the debris was removed. You could always spray them down with bug removal spray and water if needed. I would be wary of using a power washer, as it is pretty easy to damage the fins on the radiator.

 

When I did mine, I just used a shop vac with a brush attachment. It worked very well.