So with my 08 4.6 if the temp drops below zero I need to jump my truck if she sits outside. I replaced the OEM battery with one with higher CCA but this hasn't solved the problems. Any Ideas or suggestions where to start looking. I'm tired of asking co workers for jumps in the morning.

 

sounds like bad battery or bad battery connection since you have replaced the battery. Did you clean the terminals when you swapped batteries?

 

had the same problem with my 08...still has the OEM motorcraft batt (5 years old) 540 CCA..pull it when it went dead...put a meter on it and it read 11.4 VDC...pop the tops and added some water which it says not to do and threw it on the charger for a couple hours...put the meter back on it..12.8 VDC...re-installed in the truck and it fired right up...put the meter on it while it was running 14.6 VDC ...this morning it was 10 outside and it fired right up...if it happens again i will get a Diehard replacement.

 

People think its stupid to spend money on a good battery, but a good battery very rarely lets you down.

In my younger days I always ran optima yellow tops because I had a stupid loud stereo that I played all the time with the car off and it always ran well. I currently have a MC battery that came with the truck when I bought it 4 years ago and it has never failed me yet, however, these ultra cold temps we have been having sure seem to be testing it.

 

Could it be his alternator? Sounds like the battery isn't getting charged. He already replaced the battery. So, odds are, it isn't the battery itself.

 

Bad battery.

Have the battery tested.... Test the battery when its zero outside.

 

Needs to put a meter on it ...get the VDC truck off and then Running..that way he can telling if the Alt is charging..

 

Who knows how long that battery sat on the shelf before he got it. I know the local mom and pop auto store about 3 blocks from where I sit right now has batteries that are who knows how old.

 

True... good point.

 

There is no reason a new battery should have trouble starting at 0. We have much colder temps going on here (-40 over night) and mine starts right up with the new battery. Mine called it a day at the end of December when this bad cold started around here. It is still under warranty.

Check your alternator for charge and if that checks out good you may need to bring that battery back for warranty. Did you purchase a quality battery? There is a big difference between a quality battery and the cheap ones.