High pressure water will remove engine grease. No need for product with adequate pressure.
I have a 3000 psi pressure washer, so I really don't need degreasers.
A good cleaner? I usually use spray on tire foam. The cheapest available. Like Son of a Gun ... $3 a can.
Step # 1:
Spray tire foam on the ENTIRE engine bay, even the hood pad/insulation & WALK AWAY.
Can sit overnight to soften dried gunk & grime if needed. I've left it on for days... Weeks even. Reapply the next day if you want. And the next..... Engine don't care.
Step # 2:
Hose off the next time you're at a self serve car wash.
Sprays most caked up grime right off with car wash sprayer after it softens up the dirt/grime overnight (or longer). Garden hose can work after a few treatments.
Step # 3:
Drive home. .... a.k.a., drying time.
Step # 4:
Reapply foam & walk away again. Do not spray it off, leaving it on the engine & everything underhood.
Leaves underhood plastic, wire looms & hoses nice and clean & makes the painted, rubber & plastic items shine ... ... ... Instant underhood detail.
Keeps future dirt & grime from setting up allowing a simple spray off with garden hose to stay clean at your leisure.
Spray entire engine bay with tire foam BEFORE wheelin'. Keeps dirt/mud from baking on so bad. Makes for a very easy clean up by simply hosing off with a garden hose when you're done wheelin'.
Yep, spray on tire foam.
Best lazy man's underhood detailer.... Ever.
'05 Rubi Unlimited, 6-speed, Soft top, Patriot Blue
RE 4.5" Super Flex
1" spring spacers up front
1.25" JKS Body Lift
255/85/16 Maxxis Bighorns/Buckshots