Does anyone here know

[1993_M75]

I saw a wrecked police interceptor at the wrecking yard the other day and it used the radiator coolant as a power steering cooler, the p/s lines hooked up to an aluminum peice which was inline with the lower radiator hose.

If it looked like this: http://www.opconab.com/www/files/laminova/bilder/oem_picturegallery/original/bild12.jpg

Then what you were looking at was the engine oil cooler. Eventually they start leaking oil into the coolant causing the coolant overflow tank to be permanently stained brown (at least on the older models).

Most people that get used police models as beaters just remove the damn things when they start leaking since they are only useful if you sit idling all day... plus they also make it difficult to put ADDCO bars on the front (the police package front bar has a bend in the middle for clearance).