if you are not sure about the degreaser at the car wash,
just go to a regular parts store and purchase degreaser
1)if you have a Short Ram
,cover the filter,
2)if you have stock factory air box or CAI
,while engine is running spray degreaser in engine compartment on plastics head,runners,everything,try to get it on the places where its most dirty and has grime buildup.
3)use good judgement! you dont want to soak connectors and wires(they are usually not dirty anyway)you are to concentrate on the areas that are dirty(if a little overspray gets on wires its ok)dont lean over engine and spray and avoid spraying if the fans come on.
4)let it sit for a about 3 minutes,at this time you should still be spraying lightly over the engine bay.
5)dont let it dry,you can take your finger and touch certain parts that had grime and see if it has loosen up.what started off as clear degreaser should now begin to look brown or blackish on the areas that were dirty.
6)take a regular hose with adjustable nozzle and wash the engine off.
7)the less preasure you use to get the job done the better. this part is optional and this is what i do for me and you may not want to do it
8)when engine is dry i spray wd40 on plastics and on the engine(runners,valve coveretc.) then get a rag and lightly go over it to take off any excess oil(i find that it helps to get rid of any excess white stuff from the water drying and it makes the aluminum parts have a nice finish look to it.
9)the shift mechanism (if you have an Intake
on you should see it easily)i usually regrease or spray wd40 on it(to get it nice and slipery),since during the degreasing it would have been cleaned.
to me its alway good to do it yourself and not let someone with a powerwasher do it,i know a lot of people experience problems after getting it done cause the power washer knocked stuff out of place,forced water into the conectors of wire etc.besides,i dont think someone else would be more careful with your car than yourself!