I would first spray on some Gunk or similar crud loosener, let it sit awhile, and then apply the water. "Warm" is OK, "hot" less so. Also don't use the high-pressure water close to seals and gaskets and such, as it could penetrate and do bad things. Don't let the car sit afterwards, drive it so that the water blows off or evaporates.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970