Hopefully, this is not a sign of things to come.

2007 4500 4x4 got it home Sunday, now has 24xx miles(23xx mile trip home) driving around today, and started to notice that fan was louder than it had been. thinking nothing, kept driving and when i pulled into the drive, noticed the CES light. Pulled the code, and got P0643 ?? Anyways, taking it into the local commercial truck dealer tomorrow to get looked at, unless anyone has any other ideas.

Update---


Driving into the dealers today(30 miles away), truck went into "limp", reduced power, and would not go over 2000 rpm, and would not stay in OD. Dealer says fan clutch is bad, and has to order part. Not sure if the how fan clutch would cause reduced power if the truck was not running hot from it???? Engine and tranny temps were both in the normal range.

This a possible issue anyone else has seen, or am i just lucky?

What was that code for? If the fan was running full time the engine might have thrown a code for not reaching operating temperature. You can take a 4500 to pretty much any light duty dealer you want. It doesnt have to be a Medium duty(5500 and up) Dealer.
Let us know what happens.
Bill

What was that code for? If the fan was running full time the engine might have thrown a code for not reaching operating temperature. You can take a 4500 to pretty much any light duty dealer you want. It doesnt have to be a Medium duty(5500 and up) Dealer.
Let us know what happens.
Bill

The only code to show up was the P0643 "Sensor Reference Voltage "A" Circuit High" Not sure how that is related to the fan.

I did call my local dealer(Fitzgerald in Frederick) but they claimed to not work on the 4500 guess they just didnt want to deal with it.

You should have a reference book that will tell you what GM dealerships that will work on the 4500's not all GM dealerships will work on the MDT lines. Its kinda gives some problems for owners of the 4500's. That was the major disappointment when I owned the Chevy Kodiak 4500. And I didn't discover the problem until I was in the RGV in 2006. Most all GM dealerships will work on the 3500's as long as they have a Diesel Tech. Good Luck. GBY....

Update from the dealer today

Fan clutch is on national back order?!?!?! Supposedly, I am like 34th on some list...Told me to be prepared for extended wait.... Now upgraded to a SPAC case, so who knows. Either way, totally unacceptable, considering I am not convinced that will be the only problem...... just the first one that needs to be fixed. I have already called GM customer service to start a complaint. I understand as well as the next guy, that things happen, but to not have parts available it ridiculous, especialy when you are talking about a $75K vehicle. Just wondering if anyone else here is one of the 33 others waiting for this? I am really considering just going back down to a 3500 duallie, as I dont want to own a truck i cant get parts for.

Just to recap, I have now owned truck for 9 days, 4 on the road, 1 in the driveway, and 4 at the shop...... not looking like a good record so far

[/]rant off[/]
:mad::mad:

"I did call my local dealer(Fitzgerald in Frederick) but they claimed to not work on the 4500 guess they just didnt want to deal with it."

I was under the impression that any dealer Chevy or Gmc dealer can service the 4500. I would go to Corporate on the Frederick dealer.