Power Loss, won't start, busted radiator, help!
 

Girlfriend was driving my 04 Z on the open road and noticed a bit of steam coming from the hood, shortly after, the car wouldn't accelerate so she pulled over and let it cool down and called me to come take a look. I noticed the coolant reservoir was overflowing and there was a big split along the whole plastic part of the top of the radiator. Electrics seem to be playing up as well - handbrake light, oil light and engine light are all on and wont go away even after putting into diagnostic mode and clearing codes. When turning the key - before clearing codes it basically sounded like a vacuum cleaner. Like the starter motor was going but wouldn't engage, and then after clearing all I got was a fast clicking. Decided to tow it to local garage to get it diagnosed - while towing I tried to put my hazard lights on - but that turned on the rear windshield wiper instead...

Mechanic did basic diagnosis. Pulled p0340 camshaft sensor code, and said it did not do well on a compression test, and he couldn't get the engine to turn over either. Thought I'd ask for some advise here before giving him the go ahead and spend hours taking it to bits to find that it's a lost cause anyway.

Read somewhere on the altima forums that a faulty voltage regulator in the alternator can cause the acceleration problem, but could it be causing all this other crap too? Or have I most likely ceased the engine? Any help would be greatly appreciated.

my guess is you seized the motor, we can not diagnose it over the internet

Sounds like you lost a or both head gaskets and then like a typical girl, she kept driving it because it didn't come to a screeching halt. The resultant combustion pressure entering the cooling system popped the radiator. Probably also warped the head(s), hence the lack of compression. Cheapest fix is going to be replace the radiator and drop in a used '03-'05 non-revup motor.

Cheapest fix is to replace the GF.

How did he do a compression test if he can't get it to turn?

The word you're searching for is "...seized the engine". Not much help is available for such a comprehensive meltdown. I hope your girlfriend understands and is helping pay for the damage.

I also want to know how he did a compression test if he couldn't turn the motor? My ball of overwhelming knowledge tells me that you're girlfriend doesn't know a bit about cars and she drove till the engine seized!