I have a 1994 320 Hull #30 with a Perkins M30. I am in the process of replacing the mixing elbow. While taking off the old elbow the rear rubber boot on the heat exchanger fell apart I pulled the front boot off as well and pulled the copper stacking tube out of the heat exchanger. Found lots of junk inside the front rubber boot. The copper tube looks OK. Thinking about taking it to a radiator shop for a better inspection. I am not sure which way the copper stacking tube goes back. There are two oval shape openings in the tube do these face up or down orwideways. Also, where can I get those rubber boots and are there any secrets to putting them back on????? Thanks Tony