Voltmete sometimes doesnt go all the way up..

[Dabba]

So, i just replaced my driver side alt, had it rebuilt. Its been fine for a few days. Now im driving and sometimes while im stopped at a light, ill notice the voltmeter drops below the little line mark and is just in the green (almost like only one alt is charging) Yet, no alt lights come on. I mean, i guess it could be the rebuild, but should the alt light come on for either? (I know they both work, the pass side glows dim once in a blue moon, but its always had that before i had this issue)

The belt on the drivers side is loose because i only had myself to put it on. Could that be it? Otherwise im not sure why the voltmeter is telling me one thing while the lights stay off. It seems to be intermittent. I thought it only happend at idle but rpms dont seem to affect it now.

 

[Dabba]

also forgot to mention i think i have a Lift pump leak as well. I have deisel leaking upon startup from the front pass side of the block. It looks like its pooling on top of the crossmember and leaking down. Didnt look like the any lines were leaking but the pump is damp. Couldnt quite get in there when i looked quick. Any place else i should be looking and how hard is it to find/do it?

 

[OL AG '89]

loose belt

sounds like the belt loosened up as it set in the pulleys.....
Do the deflection test and see how it feels.

Can't help on the pump leak, as I haven't experienced yet.....

 

[Dabba]

Yeah, guess ill re-adjust. Any easy way to do it alone? I cant quite get it all the way over. I did think i heard it rubbing.

 

[Barrman]

Turn your key on but don't start the truck. Look at the volt meter. Wherever it is is your volt meters idea of 24.4-24.8 volts if your batteries are both charged up. Mine is about the middle of the yellow over the "-" at this point. Yours will probably be different.

Once you start the truck, you can basically watch the gauge move as each alternator kicks in. One working will get the gauge up almost to, but not all the way to the green at the top of the yellow. Both will get you somewhere in the green. Mine never gets to the little tick in the middle of the green. Yet, I have 14.4 at each battery and 28.8 across both batteries.

Try putting a volt meter across each battery and see what they are actually at. 14.4 is what the regulators in the alternators are supposed to keep them at. If one of them is lower, but above 12.4 or so. Then I would think a loose belt or loose connection is the problem.

 

[Dabba]

Man, thanks for the info, yeah maybe the new alt is acting different but mine always reached that tick. Ill test em out