I have a '87 Iroc-Z that was a 5.7 TPI with TH700.
Car is undergoing a LS1+T56 swap. As you know, the original radiator has the engine oil cooler in it.

I was wondering if there is any reasons why I couldn't use the original engine oil cooler for the power steering?

Car is going to see some serious track days.

 

The cooler in the radiator is for the transmission fluid, not engine oil. It is designed not only to cool your transmission fluid, but to bring it UP to the proper operating temperature via the coolant in the radiator. Since your swapping a T56, obviously you have no use for a transmission cooler, and you could "hook up" the power steering lines to that cooler, probably with no ill effects, but I dont see what you would gain from it.

 

Okay... but isn't the engine oil cooler also in the radiator?

 

No, the KC4 cooler routes coolant through the sandwich adapter on the filter pad. There's a heat exchanger inside.

Bad idea to use the rad for a p.st. cooler.

I've had a quality (mocal) cooler burst from a mishap w/ a KRC power steering setup. For some reason yet still unkown I had a huge pressure spike through the cooler (which is on the low pressure side of the system, in the return line to the reservoir) and the cooler developed a leak. Last thing you want is for that to happen inside the radiator.

 

I think I'd run some CLR through it and see if it looks OK on the inside. As long as the inside doesn't look compromised in any way, like thin spots, etc. I'd roll with it.