There is a fuel preheater in the system. Otherwise it's pretty similar to the 61x.

The flow is tank -> prefilter-> preheater valve -> preheater (if the thermostat in the valve is cold, otherwise it's bypassed in the preheater valve -> preheater valve -> lift pump -> main filter -> IP -> injectors -> injector return/main filter bleed/IP return -> tank.

Also note that there is no hand primer on the 60x IPs. If you get air in the system you will have to crank like crazy to re-prime.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech