Bmw 325 ix.Too cold oil

[romilos]

The BMW 325 ix has an oil cooler.
A friend of mine has this car, he has an aftermarket gauge for oil temperature.
He needs (with 150 deg out side temp) over 20mins for the oil to reach 70 C. He has nitro also (40hp) and when he runs with nitro the oil never goes above 80-90C.

Do you think that the oil is too cold? He uses Motul 300V 15/50.

He is considering a thermostat in the oil cooler system so the oil warms up quicker.

[Guy Croft]

Yes, you do need an oil system thermostat to encourage the oil to warm up quickly. Running the oil at 70 deg C for a long period prevents the oil from dispersing water and fuel vapour and reduces power.
Optimum running temperature wants to be say, 85-90 deg C.

GC

[romilos]

Τhank you Guy

What thermostat do you suggest?(let s say an 80C would be ok?)
The viscosity of the oil, would be critical gor the oil temps?