Did the 2nd coolant change on my 2005 Toyota Tacoma (4.0L V6) today. The overflow tank is integrated in to the fan shroud, so it can't be removed to clean, but does have a rubber plug over a drain nipple on the bottom of the tank. I didnt drain the tank during the first coolant change 7 years ago.
I noticed quite a bit of "sediment" in the bottom of the tank this time, so I drained the tank this time, then used a waterpick to blast everything loose and flushed the tank many times with distilled water. I collected the drained and flushed tank fluid, then filtered it through a coffee filter to collect the sediments for inspection.
This was the result, it looks and feels like light tan "mud". Didn't really feel "gritty" at all between my fingers, more like smooth "mud".
So is this remnants from the engine casting, or from where? The inside of the cooling system looked like new, no sign of any corrosion. The old coolant drained from the radiator and engine looked clean, like it was still new, and had no sign of this sediment.
I noticed quite a bit of "sediment" in the bottom of the tank this time, so I drained the tank this time, then used a waterpick to blast everything loose and flushed the tank many times with distilled water. I collected the drained and flushed tank fluid, then filtered it through a coffee filter to collect the sediments for inspection.
This was the result, it looks and feels like light tan "mud". Didn't really feel "gritty" at all between my fingers, more like smooth "mud".
So is this remnants from the engine casting, or from where? The inside of the cooling system looked like new, no sign of any corrosion. The old coolant drained from the radiator and engine looked clean, like it was still new, and had no sign of this sediment.