Well, maybe really dark brown. But that is what I just drained out of my radiator while starting the process of replacing my Opti.

I know that the coolant went in green, and now it is dark brown, almost black in color.

What would cause this? Is it something to be concerned about? I've never had coolant change color from green to dark brown/black before.

 

It could be your head gasket going out I think? You should check your oil to make sure there is not coolant contamination in the oil also. If everything looks good there I would do a compression test and if that checks out, just flush the coolant system and periodically check it to make sure its all good.

 

dirt and grunge.. usually when it goes brown, that the mixtures have not been 50 50, and more water was in your system than coolant.

To clear this, you should once a year fluch your cooling system. it cleans out your hoses, rad, block, heater core.. etc etc.. and your system will be nice and clean!

 

^^^ agree flush the system and when u do it flush the heater core separate by taking the hoses off at the water pump and run water both ways till clear.

 

Thanks for the replies. I got the water pump off right now and am soaking the harmonic balancer with PB Blaster to loosen it up. I will try flushing it out with the garden hose later, before I put the new opti on.

 

im in the exact spot, my fluid came out brown, and i have the pump and opti off, dont get the new opti till monday, is it ok if i just stick the garden hose in the one side of the head and push all the water through? i have never herd of anybody doing that lol

 

that should work. cover any holes that water could get to the oil through and hose away. lol. hoser., lol,.

 

i never did it with a garden hose. the guy at the shop always hooked it up to a machine that sucked the old crap out and put new coolant in at the same time.

 

haha hoser, nice one craby i havnt herd that one in forever