Orientation of oil cooler

Does the physical orientation of an auxiliary oil cooler matter? Like if the inlet/outlet are both at the top, or on the side, or the bottom etc? If on the side is ok, does it matter if the feed or return is higher or lower?

Thanks

Put the inlet/outlet at the top. Otherwise it'll drain when you stop the pump, and you'll end up running an artificially low oil level.

In reply to Keith Tanner: Seems obvious now, but I didn't think of that. Thank you.

Keith Tanner wrote: Put the inlet/outlet at the top. Otherwise it'll drain when you stop the pump, and you'll end up running an artificially low oil level.

There are 2 sides to this coin: This is the downside. Setting the oil level properly is a tricky and important job with this setup.

The upside is that once you find the proper oil level, you can get all the old oil out of the system when doing a change, without disconnecting any lines. With the fittings on top you can get 1-2qt of old oil left in the system.

Edit: Oh here's the easiest way to set the oil level properly in a fittings-down setup: When you're installing the cooler, don't fit it to the chassis at first, let it hang down from the car and rest on the ground, fittings up. Let the engine run up to full operating temp, then give it some revs so it goes over and the oil cooler is definitely full. Make sure the oil is topped up. Then mount the cooler in its final position, give it some time to drain and check the oil level again. This is your new "full" level.

When doing a change, I pull the fittings at the pan and use compressed air to blow out the old oil. Make sure you've got a rag over the outlet fitting when you do this, and you may want to drop the compressor down a bit from 100 psi or it's quite a dramatic thing...

Unfortunately, I learned about the artificially low levels the hard way. Cost me a couple of transmissions at a time when I really didn't want to be losing transmissions.

Keith Tanner wrote: Cost me a couple of transmissions at a time when I really didn't want to be losing transmissions.

I don't know about you but the times when I really don't want to be losing transmissions is pretty much all the times.

It's different when there's a clock running. If I lost the trans in the Targa Miata today, it would be annoying. If I lost it during the Targa Newfoundland, that would be really bad.

Seems like in a transmission it would be less of a concern given that the fluid level is usually checked with the engine running and flow through the cooler.

Not on a manual trans with a fill plug and a drain plug. NOW I'd turn the pump on. But I didn't think of that 10 years ago when this happened.