I replaced the serpentine belt that was chirping on my 2002 E450 6.8 last week. I used a Dayco belt from Autozone. It took about 2 hours although I figure I could do the same work in an hour after the OJT. Look for the label under the hood that shows the belt routing. As I recall a picture I found online for my engine was different than what I actually had. The following description is for my vehicle. I understand that other V10 configurations exist, but I suspect they would be of a similar level of difficulty.
I unlatched the air filter ring, undid a pipe clamp and folded the air intake housing over to the driver's side without disconnecting the wires to the MAF. I used a 1/2 breaker bar on the tensioner to remove the belt. I put a 18" cheater on the breaker bar just to make it more convenient to handle, but I really didn't need additional leverage.
Since the belt I was replacing only had 4K miles on it I figure that the previous owner attempted to fix this same chirp (I just bought the MH and don't know a lot about its history). That being the case, I decided to replace the tensioner and the idler pulley too. I still replaced the belt because it might have glazed from the chirping/slipping. The idler felt like it had some play in the bearing and not being familiar with the V10 setup, I decided to replace it since it only cost $17. The new one had the same play so that was probably not necessary. The new tensioner seemed to require more force to move it (subjective assessment) than the one I replaced so I suspect that maybe the tensioner spring was old and week and could have been the cause of the chirp.
The hardest part was getting the new belt on. My first mistake was trying to get the belt around the alternator, fan, idler, and tensioner then go under the vehicle and get the engine pulley, PS pump, and AC compressor. I was trying to do most of the work from the top. I spent about an hour cussing at that approach. I finally figured out that I should start with the bottom pulleys and finish up with the top. First push the belt down between the idler and tensioner and then loop down (right side of the vehicle) around the AC pulley (IIRC it was the AC on that side, not PS). I then pushed the belt down between the tensioner and the fan and looped it over the engine pulley. I let the belt sit forward of the fan pulley and rest where the fan blades join the pulley. That gave me enough belt slack to get belt over the left side PS pump pulley (IIRC again) and the alternator pulley. Now that the belt was in position on all the grooved pulleys, I pushed the tensioner and slid the belt up over the smooth curved edge of the fan pulley to get in it its final position. Released the breaker bar and that was it. I put the air filter housing back together and there is no belt noise at all now.
Although it sounds complex, it really wasn't and once I tried this approach the belt was in place in less than five minutes. I was by myself and although I could have probably used some help to hold the belt at times I did it alone. It isn't bad to do. It was my first experience with the V10 although I have done a lot of work on cars over the years. On a scale of 1 to 10 I would give it a 2 or 3.
r/ Mike