The Bosch alternator was purchased from Amazon for $157.05 plus Texas sales tax of $11.39. Ordered on Monday and delivered on Sunday. No shipping charges or core charge.

The alternator is new, not remanufactured, and it says it is assembled in the USA. It comes with a lifetime guarantee and a two year roadside assist if the alternator fails which means a jump or a tow, whichever is necessary. This is a 135-140 Amp unit which replaces the 110 Amp OEM unit that was original equipment. Installation of the unit is straightforward as the three mounting bolts line up perfectly and the electrical connections are the same as OEM and in the same places as the OEM unit.

Now the hard part. The tensioner has apparently gotten old and cranky. I pulled with both hands, used pry bars, a universal tool from Harbor Freight which didn't work and tried to roll the alternator up with the belt over the pulley. I posted a request for information how to remove the air deflector on the top of the shroud and thanks to some advice from Bullit, I removed the deflector. I placed a 2x4 across the top radiator brackets and slipped a 3/4" pipe under the belt and pried the belt up and placed the pipe on the left hand bolt (as I am looking at the alternator) and it rested there. Still not enough clearance to set the tab on the tensioner so I had a friend apply some more muscle and that gave me the space to set the tab. Placed the belt on the alternator pulley, checked the alignment with the other pulleys, pried up on the belt again and this was enough to disturb the tensioner and the belt seated properly. If I have to change this belt again, I think I will do it next to a tree and use a come-a-long or buy the special tool that is advertised for 6.0's.

The results are as follows: At 50 MPH on the road it puts out 13.6-13.8 volts with an occasional fluctuation of a high of 14.2 volts and a low of 13.2 volts in the beginning. At idle, after being warmed up, I was getting 13.6-13.7 volts with AC on and headlights on. Starting, I'm getting a quick dip into the 11's after the glow plug light goes out and with the starter turning and then it climbs up to 13 volts and then on to the 13.6-13/8 range when the glow plugs turn off. All results were considerably better than the OEM unit. I believe this alternator will meet our needs.

 

You had put in new batts not too far back, right Bob? Those numbers aren't too far off mine and I've got the Factory 140A. I still plan to run the overdrive pulley on it -- most of the lower numbers I get are at low RPM...

 

Great post, this right on time. I too pulled the trigger on this alternator and it should be here in the next day or so. I was hoping it would be a bit better than the original. Although those voltage readings are about what I'm seeing now, so I'm a bit concerned.
What is this overdrive pulley? I was wondering if the original pulley is smaller than the one that comes on the Bosch unit, and if it is I plan to swap them out. I'm more concerned with voltage at idle than anything else really, things are fine scooting down the road.

 

Josh might be along in a minute here, but I bought mine off eBay for under $20 total. It's an 8 groove 58mm pulley... I'll go try and find it and post a link.

This is the one I bought (same seller too):

http://www.ebay.com/itm/OVERDRIVE-8-GROOVE-PULLEY-Gain-output-idle-in-some-apps-FORD-ALTERNATOR-6g-3g-/170910011638?pt=Motors_Car_Truck_Parts_Accessories&hash=item27cb07d0f6&vxp=mtr

 

Here is the 58mm overdrive pulley...

http://www.ebay.com/itm/OVERDRIVE-8-GROOVE-PULLEY-Gain-output-idle-in-some-apps-FORD-ALTERNATOR-6g-3g-/170910011638?pt=Motors_Car_Truck_Parts_Accessories&hash=item27cb07d0f6&vxp=mtr
Josh

 

Did either of you take readings to see if this was an improvement and worthwhile?

 

I purchased Interstate batteries at Sams in February, 2011 and they were individually load tested in February 2013 and found to be on spec. Our Sams no longer carries the Interstate batteries and now carries the Energizer brand with the same specs and they are also made by Johnson Controls.

I to was particularly concerned about the running voltage at idle but the results were nearly identical to the voltage at 50 MPH/ 1500 RPM's.

 

what is original size and does this alter serpentine belt or tensensor.