My $.02 (I used to have a detailing business)
The regular green will do a fine job and is less harsh than the purple. If the engine is greasy then Autozone/Pep Boys sell generic purple degreaser you can dilute and use, but the regular simple green from the supermarket should be fine.
Try and keep either cleaner off the paint on the front quarter panels, bumper and grill area as it will strip off any wax that you have, or be prepared to re-wax the vehicle afterwards. The engine can be warm (actually preferred) but you should try and let it cool a little especially if you're car wash uses cold water - if there's a hot setting for the water use that. Spray the engine bay with cleaner, agitate exposed areas with a soft brush or mitt, then rinse and dry as possible. During rinsing try and stay clear of obvious electrical connections with high pressure - water will be ok, but high pressure can get past some of the seals and that's where you'll have issues.
As you are having some real heat up north, the paint should also be as cool as possible (wet it all down first if you have enough quarters) so that when the simple green get's on it there is less chance of etching, and rinse the whole front end afterwards too to make sure overspray is rinsed off.
Most self serve car washes use recycled water that's less than ideal for any "detailing" so I always would dry the vehicle afterwards.
Typical detailer scenario is start with engine compartment, clean and dry, go to wheels next, then body, starting with roof, then front end, working your way back (to the dirtiest end) rinsing each section as you go, then total dry down. Different mitts for wheels, and if you're crazy like me, different ones for upper and lower sections of panels to eliminate swirls. NEVER use the brush - unless you are the very first person to use it EVER - or you don't mind the small swirls and scratches it will leave....I always took a mitt and bucket and hand washed with that and my own soap if i have to use a coin-op bay even though signs say "no bucket/hand washing" .
The regular green will do a fine job and is less harsh than the purple. If the engine is greasy then Autozone/Pep Boys sell generic purple degreaser you can dilute and use, but the regular simple green from the supermarket should be fine.
Try and keep either cleaner off the paint on the front quarter panels, bumper and grill area as it will strip off any wax that you have, or be prepared to re-wax the vehicle afterwards. The engine can be warm (actually preferred) but you should try and let it cool a little especially if you're car wash uses cold water - if there's a hot setting for the water use that. Spray the engine bay with cleaner, agitate exposed areas with a soft brush or mitt, then rinse and dry as possible. During rinsing try and stay clear of obvious electrical connections with high pressure - water will be ok, but high pressure can get past some of the seals and that's where you'll have issues.
As you are having some real heat up north, the paint should also be as cool as possible (wet it all down first if you have enough quarters) so that when the simple green get's on it there is less chance of etching, and rinse the whole front end afterwards too to make sure overspray is rinsed off.
Most self serve car washes use recycled water that's less than ideal for any "detailing" so I always would dry the vehicle afterwards.
Typical detailer scenario is start with engine compartment, clean and dry, go to wheels next, then body, starting with roof, then front end, working your way back (to the dirtiest end) rinsing each section as you go, then total dry down. Different mitts for wheels, and if you're crazy like me, different ones for upper and lower sections of panels to eliminate swirls. NEVER use the brush - unless you are the very first person to use it EVER - or you don't mind the small swirls and scratches it will leave....I always took a mitt and bucket and hand washed with that and my own soap if i have to use a coin-op bay even though signs say "no bucket/hand washing" .
