Operating temp of cooling system

[RichZilla]

Can anyone tell me the normal operating temp of the VH45DE? Or what the Q45's radiator cap is rated to in PSi. I've got two fans on the merc and I'm still seeing apparent coolant temps of about 100 degrees celcius after driving for an hour in the hot sun and traffic.

[elwesso]

Yeah you're running way too hot... The max you shoudl see is around 90C or so... Operating temp is about 80C... Once you hit 90C you start backing the timing off because the ECU thinks its overheating...

The cap spec is 11-14psi...

[Q45tech]

Ecu timing retards begins at 91C [195F] and increments 1 degree advance reduction per 5F to a max of 5 degrees at 220F

A proper brand new radiater with correct functioning rubber shroud seals and viscous fan will hold 174-196F. Ideal per FSM is 176F.

Oem rad is designed for a 0.9 bar or 13.2 psi cap