Batt light on my 02Supercab 4.6-5spd came on 60 miles from home. At highway speeds and high revs light would go off but come on at idle and slower speeds. Made it home ok and purchased alternator from dealer. They said Ford only has "reman" alternators for this vintage now. One dealer wanted $242 another $304. OUCH for a reman alternator (with no pulley)! Installation was fairly easy but worried about getting enough torque on pulley nut with just hand tools. After install, checked batt voltage (12V). Upon starting went to 14V. After quick ride around block the alternator was too hot to keep my hand on it and Whine was very noticeable. I assume that some extra load would come from battery getting recharged but what is Normal Temp? Pulley turned very smoothly, what's up with the Whine? Seemed like a fairly easy DIY but now I wished I had taken to shop. Truck has 135K and I love it. My third F150 (all manual,4X4,all silver,all went >130K). Thanks for any suggestions or comments.

 

You can't without damaging the fan. It takes an impact driver.If you had read the paperwork that SHOULD have been in the box, all alternators specifically say to FULLY recharge the battery before connecting a replacement alt. It's possible that you've damaged the new alt.

 

Thanks for reply. I broke the seal on the the new alternator box while I was at the parts counter. There was no literature, tags, or warnings at all inside the box. I hope I didn't fry the new alternator. The shaft on the alternator appears to be straight (no taper and no keys). What keeps it tight on the shaft? Just the force of the nut holding it?

 

Yes, just the nut. That's why an impact driver is required.

 

Ive replaced my alternators several times and faced the same problem. However I would not use an Impact Wrench to install the nut. I'm not going to get into the theory of why/or not, but I'll tell you what I do. :

If not equipped with the correct 8 Rib Pulley I buy or order one from the Dealer. (Sometimes parts people don't recognize the difference between a 4.6Ltr.V-8 F-150 and a Crown Vic.)

The issue is that there really is no Woodruff Key to properly index the pulley to allow proper tightening.
I would secure the Alternator in an appropriate Bench Vise. Locate the rotator within the alternator, and block it's rotation using a dull, flat aluminum (or similar) bar. Be careful not to nick the rotator's wiring; just slip the bar into a spacer on the rotators steel body. Using a good quality 1/2" Socket Wrench torque down the nut to about 48Ft./Lbs. (typical). For a little insurance you can lightly coat the threads of the Alternator Shaft with several drops of "Thread-Lock" if you want.

If you don't treat this problem it could cause a dangerous condition of having the belt, pulley, e.t.c flying off at very high velocity at a very inconvenient time.
Peace

 

SAE wouldn't approve of that technique. Neither would ASE or Ford. The torque spec on the pulley nut is 60-100 lb-ft, and Ford says to disassemble the alt and clamp the rotor in a soft-jawed vise to set or break the nut. Digging into the windings &/or prying against the edge of the rotor is just asking for an internal short. But if you hold the pulley while impacting the nut, the alt doesn't spin and doesn't get any more stress than from a revving or misfiring engine.

 

Thanks to all for replys. Took to shop and they checked voltage, charging current, and physical temp of alternator. All normal. Comment was that when alt is newly installed it was probably putting out max current to catch up battery discharge. Since then I've driven ~200 miles with no issues. Alternator feels warm but not hot and voltages ok. Driving home last night, BATT light comes on again. This time revving engine doesn't put it out. Continued on home and it went out eventually and hasn't come on again. Driving short trips everything seems ok again, voltages ok. My theory is pulley slipping so I've borrowed an impact wrench and I'm going to tighten. I will mark nut beforehand to see if it moves at all. My guy at the shop says it's likely a bad plate in the battery which is intermittently causing the problem. Battery is 12 months old. It has 3 yr free replacement from PepBoyz so I could see if they will replace. What do you guys think? As always, thanks for the info!

 

You should NEVER run a new alternator until the battery is fully charged.I think they'll test it, which is what you should ask them to do before suggesting that they replace it. Many parts stores test them free in the parking lot. I'm surprised the alternator guy didn't test the batt.

 

I took the battery (11 months old with 3yr free repl)back to PepBoys. They tested it and said it was fine. I explained that the problem was intermittent (dynamic not static) and truck had new alternator and was checked twice for current, etc at the shop. They were not interested and wouldn't give me a replacement. I went to the local Sears and bought a DieHard with the same CCA. Installed DieHard and haven't had a problem since then. If PepBoys had given me a new one they would have had a customer for life. Now I have a battery with probably a cracked or loose plate which I don't dare put in anything. I hope that the problem is permanently solved. Time will tell. Thanks for the help.