how cold is too cold for oil temps?

Originally Posted by Dustin@Z1

No worries. This is perfectly normal. There is a slight flaw in the VQ37VHR's design that we have discovered. Like I have mentioned in the past, over cooling the engine oil is just as detrimental as over heating it. The general oil temp range you want to see on a properly installed oil temp gauge is between 190 ~ 210 ideally.

This engine oil temp is what you want to see COMING OUT from the motor. In the case of the 370z and any add-on oil cooler, you are actually getting a false reading. Since the factory temp gauge reads engine oil as it exits the Oil Filter, you are actually reading the oil temp coming directly from the oil cooler. The flow pattern for engine oil on a 370z is as follows:

Pick Up Tube --> Oil Pump --> Oil Filter IN --> Oil Filter Out --> Oil Cooler --> Engine Block (Temp and Pressure gauges are located in this galley)

The temp you are reading is actually what is going back INTO the engine (which is perfect). By the time it cycles thru the engine, you can expect to see engine temps in 200 degree range.

As for the thermostatic sandwich plate, it will bypass roughly 80% of the oil back into the engine when too cold. It will still flow ~ 20% thru the oil cooler (preventing air pockets from forming).

To get a TRUE Oil Temp reading, you would need to install an inline oil temp gauge coming out from the Thermostatic Sandwich plate before the oil cooler.

I hope that this answers some questions and relieves some stress! If you have an questions, definitly give me a shout.