Coolant disappearing and Electrical short, maybe?

Any information provided is greatly appreciated. I have 1997 Suburban that I'm starting to get frustrated with. I had to replace a bad fuel pump in May 2005 while on family vacation, and
now, 18 months later it buzzing so loud I can hear it from the driver's seat, engine running and door closed. I will be replacing it this weekend.
The last 3-4 months my antifreeze seems like it is always low. I don't see any leaks, but am continuing to top it off. I did a pressure check and it held 16 psi very well. I also replaced the cap. I'm not sure what is happening to the coolant. If my intake gasket is leaking, wouldn't it show on the pressure test? Any tips?
Yesterday morning the truck was stone dead. I pulled out my battery charger and got it running again, but 6 hours later it was stone dead again. I had a tough time getting it running the second time. While the battery charger was running, the power door locks were freaking out and locking and unlocking by themselves. I was able to get the truck running again and drove around until the battery was charged. I then disconnected the battery over-night to see if it was bad, and it started the truck no problem. While driving it now, when I turn up the radio, the louder I go, the speakers start to distort, more and more. Could an electrical short cause this? I just picked up a multi-meter and am going to check the battery draw when turned off. Any other advice or thoughts?
Thanks, Jeff S.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The intake manifold on the 5.7 Vortec is very prone to leaking coolant with age. Usually in the back of the motor due to cheap plastic gaskets that were used that shrink and crack with age. As engine heats up and cools it expands and contracts is parts some and causing it to leak more sometimes than others (the reason is tested okay). If you have it repaired, do not use a plastic type GM gasket, use a after market one that is not. On the fuel pump issue, there is a lot of misunderstanding on them. They are truely lubed and cooled by the fuel in the tank and if you run it low a lot, it will shorten its life span. In over 17 years of driving GM vehicles with in tank pumps I have yet to replace one because I rarely let it get below a 1/4 tank and usually refill just below a 1/2 most of the time. ( do still have one that is 17 years old now too in a 40 gallon factory tank) They pump used on vortec motors can disappate about 100 watts of energy in tank at times in the form of heat. This is over 300 BTU's and one BTU can heat one pound of water 1 degree C in a hour so 300 BTU's could heat 5 gallons of fuel about 12 to 15 degrees in one hour and if it is warm out, the gas can boil to vapor in bearing in motor when fuel is volume is low and no mass to accept heat which can shorten lifespan. TBI ones use less power because of lower line pressures and are a bit more tolerant. ----------------- TheSnoMan.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.