Thermostatic or not?? Pics included. Bought cooler off member
 

I bought a 25 row oil cooler from a forum member that's a buddy of mine and he could not remember if the plate was considered thermostatic or not just wanted to make sure in preparation so I let the car warm up on cold days or if it's protected by thermostatic valve. It's an older series STILLEN cooler. I know all their modern kits come automatically with the thermostatic plate I just wanted to make sure

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Sides are blank. No threaded valve or bolt.

Doesn't look like a thermostatic plate to me.

Yeah. I don't think it is.

Test it, Boil some water and see if the coiled spring in Pic #2 moves. Or find a part number and google it. Looks like a pressure bypass to me

Yeah I read the boiling water test on a forum. Gonna try that see if it works. THANKS!!!

What's a pressure bypass?? Different then thermostatic?

Pressure bypass stops/reduces the flow of oil to the cooler, If the oil is very cold or the line is blocked, some or all of the oil will bypass the cooler to keep from damaging the cooler system but still supply oil to the motor.

I tested the plate in pot of boiling water. At high heat the internal coil flap CLOSED when submerged in HOT water, I'm assuming this is to route all fluids (oil) through the fittings and would be into the oil cooler.

When submerged in cool water (same level) the coil flap opened. In which I assume making it thermostatic allowing for oil to flow back to the motor and heat more quickly.

I found what appears to be the kit i have on CZP website STILLEN 400750 (same core and plate I have) listed as THERMOSTATIC BYPASS.

Thanks for all the help and information.

Going to install the cooler either way. Possibly upgrade the plate down the road to a guaranteed thermo housing