Here's what I just did on mine...
I liberally applied WD40 to all the surfaces underhood. The WD40 acts as a degreaser but also protects somewhat against water penetration. I let it soak in for about 10 minutes, then I hosed it down in the driveway and followed up with a bucket of hot soapy water (I used Dawn for its degreasing properties), a medium-stiff bristled brush, and an old mitt. After a good scrubbing of every exposed surface, I then rinsed everything down really good with lots of clean water from the waterhose. I dropped the hood and washed the car, allowing the engine to dry somewhat. After washing the exterior, I dried it before drying and polishing the engine compartment. As someone else mentioned, Armor All (or some other silicone-based protectant) is a good idea to use on the rubber seals and hoses (I use spray silicone, which I think lasts longer). Have fun!<p>1998 A4 2.8 QMS
1999 Camaro SS #1411
2000 Durango R/T