My 2003 350z (115k on it) started overheating at idle. If I turn the heater on, it will settle at 1/2 way. But once I start driving or revving the engine, that will also drop the temp. Example lets say I'm going down a hill and I downshift into 4th to slow my car down at 4k revs, my temp will drop down. I was told my water pump is starting to go since it's chain driven. But while doing research on it, it sounds like your pump is either good or bad, nothing in between. I'm just trying to figure out what is wrong before going on a wild goose hunt. I'm only 18 and can't afford to just throw money at shops.
Do you guys think it is:
1. Air in system
2. Bad thermostat
3. Water pump

I would really appreciate any help or advice.
Thanks

 

What are your electric cooling fans doing? Do they run?

 

Yea they kick on and are pretty loud. I just burped the coolant. (Put on hill, funnel in cap method)

 

There was no air in the system. Just drove car and it started overheating again.

 

Air.
Drain it and fill it following the instructions PRECISELY. Note the extremely slow fill rate.

 

I think I found out the problem, my radiator just blew.... Luckily the car is fine. Do you guys think something else caused my radiator to go?

 

you probably had corrosion in the radiator, and it built up until it fully clogged. Enough heat and pressure, and boom.


You buy the car new or used? Check for that stop-leak crap, it looks like rusty mud usually. If you find it, you need to hardcore flush the entire system, and replace the WP, TS, and obviously, your broken radiator.


Good luck sir..