How to Tell If Oil Cooler Sandwich Plate Is Thermostatic?
 

Is there a physical marking?

I bought a used unit from a member who stated it was thermostatic. Upon starting the car for the first time after install I can immediately feel the fittings on the oil cooler as well as the core heating. The oil temp. gauge hadn't even left the bottom yet!

Thanks for any help you can lend. :tiphat:

Few, if any, thermo-plates are positive shut-off - there will always be a little flow through the cooler.

I sure hope that's the case. Thanks for the speedy response. Still in for other's input.

All thermostatic plates flow oil when closed. The reason behind it is that the cooler has some oil flow at all times. This warms the oil in the cooler, so that when the plate opens up. The oil system is not shocked with cold oil.

Plates with thermostatic have an extra "nub" on the backside with the thermostat valve is encased.
Plates without have a rounded back and just the input/output ports

As mentioned above, ALL thermostatic plates allow around 10% flow at all times to prevent air locking and cold shock in the rad.

Anything north of the Mason-Dixon line really should be using thermo plate. below that, not really needed (for all 3 days of the year it gets actually cold), just don't drive like a moron (keep throttle on roll and below 4k shitfting) until you hit at least 140 temp - and if you are driving before minimum 1-2 min warm up time... sell your Z now or start saving for a new engine later lol:inoutroflpuke:

Can you ID the 'nub" with a pic? :tiphat:

First picture here on Fast Intentions Page <-- They have pictures of both side by side.

Going to have to get a look next time on jacks. Can't remember if that "nub" was there or not. Was installing front fog lights at the same time, lots going on that day.
Thank you for the link. :tiphat: