I'm getting this code on my 2004, 5.3 4X4. The voltage/charging gauge looks ok but a little lower than usual. The truck has 165k on it with the stock alternator.

I looked at the serpintine belt and its moving. This vehicle is all stock except for the water pump being replaced and the system flushed and regular (green) coolant being replaced.

The alternator does seem to be making some noises. What is the best way to test the alternator and/or regulator? If these are bad can I just purchase rebuilt ones at a parts shop? Or will I regret giving up my factory alternator as a core later? Alternator/starter shops seem to be a rare thing these days.

 

I've had better luck replacing alternators with a rebuilt one rather than a new one.

 

I don't know where you live Dan, but for many years I have had alternators and starters rebuilt rather than buying a so called rebuilt alternator from a parts house. I recently had a Chevy one rebuilt at a shop that is about 20 miles from my house. For $55 they replaced the bearings, diode trio, regulator, brushes and pulley and then tested it on their machine which showed amp and voltage output plus it showed that there was no bearing noise. That made it an essentially new alternator. A rebuilt alternator at a local national auto parts house chain wanted $125 for a rebuilt one plus the old alternator. I have found that most of the so called rebuilt alternators you get at the chain stores only replace the defective part and don't go through the whole thing, so you really don't know what you are getting with one of those. I have found that you are lucky to get through the warranty period without it going bad again. I would find the closest quality rebuilder and send your alternator to them if it is too far to drive, but of course that means you'll need other transportation while yours is being rebuilt. The shop I use will rebuild my alternators and starters while I wait if I give them a call before going to their shop. You could get your local parts house to do a free test on yours on their machine, but at 165,000 miles, you are probably in need of a rebuild or not far from it. You will save a lot of money too by going to a rebuilder rather than a parts house.

 

Any auto parts place can test your alternator fairly definitely with it off the car. Shops like pepboys have a machine that can check it on the car pretty accurately this test should take a five minutes or so, not 1 minute or they are using a cheap machine. was $15 last time I checked.

 

I watched a YouTube video for my truck on the alternator. It wasn't highly technical, but gave me the basic steps for R&R. My factory alternator was only 105 amp.


I located a rebuild shop for starters and alternators in Oakland (will be good to know if working on anything that needs rebuilding). They could rebuild it for me for $109 (105 amp) or $119 (145 amp) with core return in about two hours if I waited. Oakland is 45 minutes from me during noncommute hours and one $5 toll. They had rebuilt ones there that they rebuild on site for about $20 more for each one.

I just hopped over the bridge and 15 minutes away to Autozone. They tested the removed alternator and it was bad on all three tests. With 165k on the truck, it wasn't a bad run and it's time had come. They had new alternators for about $179 and $172 before core return. They would only give me $10, so I kept my core figuring if the new and/or rebuilt ones are crap and research says to take the old one back for a rebuild, I'd still have that option down the road if I kept my core. For about $50 more I figured it was better than the extra hour of driving time and additional time to wait for a rebuild of the old or to buy one off the shelf in Oakland, so I just bought the new one for $179 for the 145amp at the shop close by.

The call to the alternator shop was worth while. He said the bigger (145 amp) alternator bolts right into the original bracket, but that I'd need a slightly larger serpentine belt. So I picked that up too! He also indicated that the increased swap would have no adverse impact running on the truck with respect to the computer or other electronics and would be helpful if I were to run more electronic accessories.

The truck runs really well now with the upgraded alternator. It feels like it pulls better and the charging on the gauge is strong.