i just recently drained my radiator and put new fluid in. i have a 01 gsr with a ls/vtec. i now notice that my fluid is getting darker in color in the backup tank( the small clear plastic container over by the intake). it has a black tint to the fluid now. is this something i should worry about? thanks in advance!

 

i dont know if this relates, but in my mom in laws old toyota previa. coolant turned brown imediatly after cycling. turns out it was thermostat.

 

the thermostat is fairly new. maybe 5000 miles at the most

 

it isn't oily is it?

 

kinda looks like oil but i havent felt it. it is pretty dark and my oil is still clear due it only has 200 miles on it since last oil change. i wouldnt guess it to be oil but ill check that out.

 

u drained it but did u flush it(the block)? try doing that with all new rad fluid again..

 

it was drained but not flushed.

 

well what was left in the block is probably what is making the new fluid darker,flush the rad,block,then refill..