Matt temp gauge climbing at idle not in motion can be due to heat soak in the engine bay. Loss of coolant from the over flow might be a indication of damage or a failed water seal, be sure its coming from the over flow and not from any coolant lines ( at least in my case), I highly recommend you do the "fan switch" mod where you can turn your fans on high instently. Check your lower spark plugs for any signs of wetness coolant smell. Good luck

 

so the suggestions are to replace the radiator or rebuild the engine....... quite the spread of options you got here

 

yeah sucks

 

maybe try the easier, insanely cheaper and quicker turnaround method of replacing the radiator. maybe youll get lucky and that will be all it is. in addition to that, the mishimoto is no good anyway. so even if it doesn't work, its not a waste.

 

I think the stock rad would be in the 38/40mm range.....not 25. Undertray would help!