im new to this so please bear with me, the battery on the passenger side, i have replaced 3 times this year it keeps on leaking after about 3 months, i have to replace the plate that it sits on, the old one rusted out and everthing. I have had it at the gmc dealer here they said nothen is wrong but bad battery. They tested the battery, the alt and all said its a common problem but i dont think so. when you start the truck after it sits for a hour or longer the volt meter reads about 9 after about 2 mins it goes to 14 15 and runs good, can somone help me please

moved to electrical. hopefully you get some help here.

There are a couple things. The hood could leak water onto the battery and make it boilover, and the passenger side battery cable bolt can be too long piercing the battery causing it to leak. I would try replacing with an AGM battery like DEKA.

The voltage issue seems normal, as it can take alot to start these trucks. The glowplug controller uses alot of amps. I believe mine does the same.

here is what they said this morning, got a new battery, new cable bolts to battery and cables, the voltage was 12.57, measured 1697 CCA, rated 770 CCA, temp 98 , cranking volts 11.59, , charging system no load 14.25 with load 14.10,

if it could be the hood what is the fix for that

You can put a piece of aluminum over the top of the battery so that if water gets on top, it doesn't get in the cells. Or you can get an AGM battery that water can't get into...

I have come to the conclusion after reading many of these posts that the problem is heat. The passenger side battery is located near the turbo and exhaust as well as far away from fresh air coming in throught the grill. It can't do anything but get to hot there. The only solution seems to be to switch to an AGM which both handles the heat better as well as the fact that it is sealed so no leaking concerns.

Just curious, where are you located and what have the temps been running there?

im in central ky, its been 90 to 100 the past few days, but it does this hot and cold even in the winter, this past winter was anywhere from 0 to 15 and up, the temp really does not change if it does it or anything. i have a talked to another guy this afternoon about it, he checked out as much as he could, he thinks same thing, heat causing it from turbo and not getting enough air, i ordered 2 new batteries Optima red top and 2 battery insualtor kits for them

I have original Delco's in mine and they are doing good. I live in Texas and its always hot. Maybe the heat thing just happens in some trucks?

i have been all over pulling my goosneck with horses and this didnt start until last october, its just about to have 100k on it, its been to Fl several times, CA a few times and tons to NY and never had any problems till last oct i dont no if he is feeding me a line of bs or not, but i guess its worth a shot

Diesail is pretty knowledgeable in the electrical department, so I'd probably listen and try what he said.

works for me, ill let ya know what goes on the next few days and all, thanks for helping me everone

No prob man, hope it works out...

Did they also load test the drivers side battery, you have to check the batteries independently to get a good load test reading. Did you clean the terminals on the drivers side battery also. GM has always had a problem with battery cables corroding inside the rubber casing causing low voltage to one battery and overcharging the other, it has been talked about alot in other posts on this site. I had the same problem with my truck, most of my problem was , the terminals were very corroded under the rubber boots on the ends of the battery cables, I cleaned them and used baking soda to wash off all the residue and haven't had a problem since . this is just a couple of more things you might want to look at. good luck charlie