In continuing efforts to combat the overheating problems in our project DSM, we purchased a nice aluminum C&R radiator with an integral 12" Spal slim line fan. Our first reaction was wow.
Removing the stock radiator is a simple task, drain the coolant, unbolt the two brackets that hold the top of the radiator, disconnect the upper and lower hose, unplug the fans, and yank it out.
The new C&R unit goes right back in the same way. The only difference is that the Spal fan comes with a generic plug that will not plug into the factory DSM wiring harness. To account for this, we chopped the connector off the old AC fan. The DSM connector has four wires coming out of it. Two are for low speed fan operation and the other two are for high speed operation. The difference between the sets is the amount of voltage each supplies to the fan motor. To make sure we wired the new fan in correctly, we took the factory connector, stripped the ends of all four wires, plugged it into the car and turned on the fans via DSMLink. With a multimeter we tested each lead and found the low/high wires (the two blue wires) and the respective ground wires (the two black wires). When wiring the plug into the Spal fan, we simply tied the low/high wires together into the (+) wire on the fan and the two ground wires to the (-) wire. Simple.
While the old radiator was out, we though it would be a good time to flush the cooling system and ad some fresh coolant with a new bottle of Redline Water Wetter. Along with the coolant flush, we replaced the thermostat with a new factory 180 degree unit. (The stock thermostat opens at 190 degrees) We also replaced the old worn out radiator cap. Check the picture to see how corroded the old parts were.
When we first fired the car up and were letting it warm up while checking for leaks and making sure everything was buttoned up properly, it was apparent that the new cooling system was up to par. Where as before the car could not idle for very long without the coolant temperature slowly creeping up, it now held rock steady despite our paranoid checking. We had never realized how leaky the old radiator cap was until the first maiden test drive. With the new cap, the coolant was actually allowed to reach the pressure it should have without boiling out of this system. Unfortunately, this pressure proved too much for the hose clamped "custom" lower radiator hose. One of the connections let loose, showering everything with coolant, getting the engine bay filthy, and letting off a very impressive cloud of white smoke. Oh well, we upgrade one part only to find the next weakest link. Guess we will have to fab that metal lower radiator hose we have been talking about for months.