Sounds correct, and in my case it gets cooled on the way back to the reservoir.

I picked up one of these on eBay for under $50. Like you said no coolers on oil on merc sbc setups. I put one of these in on P/S and bought a bigger one for my oil. There is substantial friction from that pump on the engine. Could you be fine without it… probably. I seriously considered it myself. But 1.25” hose is cheap, cooler was $50. regardless of your cooling setup should be pretty easy to rig up on the return side. I’d prefer to spend a few bucks on my cooling system than risk damage to my rack or my pump on my I/O setup.

I guess this summer I'll be checking the temps on my lines and helm pump. Just out of curiosity.

Sb and I are not talking about seastar style setups.

We’re talking about I/O setups. You’ll have a fairly large engine constantly turning the power steering pump that fluid is used in actuating the rack and pinion on the transom assembly. That fluid gets really hot. Most cars have a dedicated P/S cooler or it is part of the radiator. boats typically have a heat exchanger cooled by raw water. I’ve never heard of a sea star setup needing a cooler and wouldn’t mess with it unless recommended. But as another person posted it gets hot. Which makes sense as fluid doesn’t like compression but I’d want proof Seastar setups needed it before doing that.

hope that makes sense.

Tha system I have is IMCO full hyd. The reason I have a question about this my engine oil cooler and steering cooler are all in one 21" long. If I do away with the steering cooler I can install a longer engine oil cooler. If I knew how to post pictures I would.

click the square box next to the smiley face on the header to post pictures

This is the picture of the oil cooler. Thanks for the help with uploading pictures.