Sadness + Volt Meter spike & Radiator

[Django]

1990 gts
The Sadness:

So not that long ago,i was driving in morning rush hour traffic, and a guy in a lifted truck cuts me off and stops short. I ended up hitting his tow hitch and slid under his bumper. His truck is fine (lucky), mine wasn't.
I ended up being able to pull out most of the bends on my bumper, but his hitch left a 3-4 inch hole on it (though its not too bad. Until i can get a new bumper, ill probably get a license plate relocater to help mask it).
My faux cf grill piece broke, but i replaced it with a new one.
My hood got bent in half and the latch got bent out of shape, but i found a red hood from an st and sanded it down and spray painted it black and I bent the latch pretty well and it works now.
My crash bar got bent up, so i found one at a yard and put it on.
My corner drl/parking lights were smashed up, but I bought some gt4 clear ones (the ones with the raised part) from a guy off alltrac.net
My Head light housings were mostly fine, a few bends and some cracks on the eye lid trim pieces, but i was able to very carefully reshape the housings, so you can barely tell. Unfortunately, the bends broke my actual lamps, so i ordered some projectors from ebay with h4s and a white led halo and put them in.
The tow hitch also, after bending my crash bar, put a hole in my radiator. so i replaced the radiator (for the first time).

The Volt Spike issue:
So when I put the projectors in, I wired the drl and the led halo together, and spliced into my parking/drl's. I wrapped all the wire up with electrical tape and put rubber casings around all of the wires. About 2 days after, about 70% of the time, when I turn my car on, my battery light comes on and the volt meter spikes almost to the max like 18v. This happens for about 3-10 minutes (it varies) and then the light turns off and the meter drops down to normal.
Just for more info, The battery is about 5 months old as well as the alternator. I also have an 800watt amp and sub hooked up.
I know the batt or alt are the first things to check out, but since they are relatively new, i really don't think that is the issue. There is some of that white/green corrosion that builds up on my cables on both the pos and neg terminals, so I am thinking and hoping that if i replace my cables, the problem will be fixed. Also, might possibly need to upgrade my battery to a red/yellow top. Im going to try the cables first because they are cheaper.
I am wondering if anyone else has had a similar problem, or if anyone has some input as to what my problem might be.

Secondly, I replaced my Radiator. It was my first time doing this particular fix. I believe I did everything correctly. The car runs well and all (aside from volt spike) but when I park my car after driving maybe 20+ min, when I exit my vehicle, I can hear the rad bubbling and grumbling from under the hood.
I never noticed this sound before on this or any other car I have owned. Did I f something up? Is that Normal?

Any input would be greatly appreciated.

So to finish the story, Everything is on the car, and its pretty **** straight still, all things considered. The black hood isn't even bad because my spray job came out surprisingly well, and it matches my black rims. There is a guy i know selling a rc bumper i meant to buy, but this all happened during the week i was moving to a new apartment, so after setting up cable/interweb and all of the deposits and buying furniture, fixing my car, etc, my accounts are low so i have to put off the bumper...for now. Im also debating painting it. I want to...but it'll cost almost as much as the car is worth...Anyways, ill take some pics of its current condition and post them in a while.

[123crazy]

It might have to do with the light... bcuz when i first got my hid light. i was messing with the wireing too much and i guess i touched the bulb.?. idk but after a while my battery light started to turn on.. and it wasnt till the bulb finally blew out and i installed new bi xenon bulbs.. now my battery light wont turn on... idk if it jad to do anything with the bulb or what.. but thats how mine got fixed..

[123crazy]

about the radiator.. i heard the same thing it turned out to be low on water..

[Old_El_Paseo]

did the same thing to me when i rebuild both 5sfe. i think these engines do that if you dont bleed system enough, try to crush hoses and circulate the water enough, get every bubble out of there and make sure the system keeps its pressure also.

but if the bubbles are loud, then its overheating, happened to me once when my fan fuse burnt, very loud bubbles on a 1000 km rebuild engine, i wanted tro cry. luckily there seems to be no damage.