My car has been overheating and I finally got around to taking it to be looked at. My mechanic told me the radiator was cracked, so I ended up getting a good deal on an aluminum racing style radiator. I installed it today and let the car run for a good 15 minutes before driving just to make sure it was not running hot or leaking and it wasnt, so I took it for a spin and the temperature started climbing and going right back down multiple times. I did have the fan unplugged cause I also installed a Kidd racing rmf replica header and it wouldnt clear the stock fan. I got home and looked for leaks or anything and it was all good. My next thought is the heater core or maybe if im lucky the thermostat, but would just like some opinions before I go fixing stuff that doesnt need to be fixed. It stumped me cause the temperature would go a little over half way and just go right back down.

 

so you are driving around with the cooling fan unplugged and you are wondering why the gauge is fluctuating? do you know what the cooling fan is used for?

im positive you still have air in the system too...

good luck

 

x2

 

sounds like your t-stat is stuck open.

temps will climb when u are sitting still, then once you start driving the air going through the rad will cool the coolant down, and since the t-stat is stuck open, it will bring the temps way down.

if the t-stat was functioning, it would close, and the coolant that is nice and warm inside the block will stay in there, until the temp rises enough to crack the t-stat.

make sense?

 

Problem fixed itself, left the car on for 20 minutes without the radiator cap to relieve air and drove around all day and the needle didnt move. Slimfan is on its way, thanks everyone for the help.