I am going to replace the timing belt and related parts this weekend on my 03 Neon, had a question. After completing the job, the manual says to use the DRB tool to "relearn cam crank". I assume this is to adjust for any minor changes in the cam position relative to the crank after the new belt install. I don't have access to the factory tool unless taken to a dealer. My question is, does this have to be done or will the computer relearn this on it's own after driving
This relearn procedure is not necessary. With the ignition off, there is no electrical function in the crankshaft position sensor and cam position sensor. The engine controller will not know that the crankshaft and/or camshaft have been turned. When the engine is started, signals are generated by both of these sensors and the engine controller relearns the phasing again between the crankshaft and camshaft.
I did purchase the complete CRP timing belt kit which also has a new tensioner and water pump. Also have access to a damper remover and installer with the correct 12-1.75 thread. Seems that most I have seen for rent are the wrong thread (12-1.5).
If you replace the water pump, you will need to remove the rear timing cover. It sits between the engine block and head and the timing belt. To remove this cover you will need to remove the camshaft sprocket.
The service manual indicates to position the crankshaft timing mark such that the #1 cylinder is at top, dead center (TDC) and the camshaft timing mark is aligned with its index. Since this is an interference engine turning the camshaft (with timing belt removed) can cause a valve to open and hit a piston in the TDC position. I modified this procedure and found it to be more forgiving.
After removing the crankshaft pulley assembly and before removing the timing belt, I turned the crankshaft clockwise and stopped it at 90 degrees before top dead center. This also positioned the camshaft at 45 degrees before its alignment to its index mark. I used white marker and indexed / marked 2 sprocket teeth on the crankshaft and camshaft to marks on the engine. These became new alignment marks between crankshaft and camshaft. Then I removed the timing belt.
The reason for stopping the crankshaft at 90 degrees before TDC is that places all 4 pistons at the midpoint of their travel in the cylinder bore. If you accidentally turn the camshaft (it will happen when trying to loosen the camshaft sprocket bolt), no piston is close to a valve and so no inadvertent valve damage will occur.
Note the position and mounting of the tensioner pulley and spring tang to its bracket before you remove them. It will help upon reassembly.
Depending upon the miles on your engine you might want to replace the crankshaft and camshaft seals while you have the timing components disassembled.