Hey guys, I recently made an oil cooler for my car. Unfortunately it was leaking at the fitting so I havent had a chance to fix it but this prompted a thought. Im worried that the way I have set the cooler up, it will drain out each time I turn off the car. The cooler is currently in in the passenger side headlight area. It is 8.5x11 and is mounted vertical in relation to the fittings. One fitting is above the frame and the other is below it. Im concerned that the oil will drain out of the lower fitting back into the block and each time I turn on the engine the entire cooler will have to fill before I get oil pressure. Is this the case or does the thermostat prevent this? Does the thermostat even make a perfect seal?

Mine is mounted the same way and I have a sandwich plate between the filter & block. I can't remember if it has the built in thermostat or not but I always have good oil pressure after startup, even when it's been sitting awhile. Eight years on and no issues yet, knock on wood!

That's good to here. The first time I turned the car on it took my warning light (20psi) a few seconds to turn off. Of course due to filling the cooler for the first time. I only started it a second time shortly after and realized I had a leak. However, the light still took 2 or 3 seconds to turn off. Normally it is instant.

I plan to test it again once I have the fitting welded on. Yeah I miss threaded it

On Stock, Plate, there is a sort of one way valve which keeps some oil in pickup line (thus prevents sucking air) I also use a sand which plate while others go Turbo oil cooler and fittings. K&N filters are said to have a check valve in them to help build oil pressure on start up.
I've had problems with male filter fitting coming off on filter changes which is a PITA.

Thanks, I should have updated. After some more research I found out about the check valves. I purchased one from Summit and installed it inline on the outlet hose to the cooler.