In line stat are the way to go
Greetings
PROBLEM
Four years I have struggled with my V8 overheating. I bought an OBDC and plugged it in and used my iPhone to monitor the temperature. I did this because the gauge is completely useless. It used to run at 105 to 110 degrees. After a new radiator it got hotter. On the highway, on hills at night in the cool it was always hot hot hot. I replaced the viscous fan. It had extra fans, everything was checked and changed out to no avail. I also bought an engine watchdog and found that it was running about 3 degrees below that showing from the OBDC (which comes from the actual temp sender)
SOLUTION
Murray, at Jagrover Spares in Brisbane got sick of all of the engines overheating and blowing and liners slipping and head gaskets popping and radiators popping and I even saw one of the thermostats with a huge split in its side due to excessive temperature and pressure. He has totally redesigned the coolant flow and he now uses an in-line thermostat running at 82 degrees, with a slight drillhole modification. He has done away with the stupid BMW heart valve monstrosity, and my D2V8 now sits on 84 to 89 degrees. I cannot thank him enough and urge all D2 and P38 owners to contact him. (07) 3857 5763. He has actually worked it out and my vehicle is fantastically cool just like the old ranges and disco ones of yesterday. This works for p38s too. He has the hoses and inline thermostat that fit and work. Hallelujah.