ford460bigblock

today i saw that there was black/greens jell in my coolent tank. were is from and is this bad. could this be casue the car was sitting for 4 yrs its a 96 2.2.

Tookie

I expect the goo is comprised of mold and some type of fungus, caused by any organics the might have found a home there. Be careful if you breath or touch the stuff. If the system is flushable, use a good quality flush and follow it with a couple of rinse flushes. Watch for leaks; as its surprising what a fungus/mold can add to it's menu over time.

deadBird

It breaks down over time. Also it could be stop leak. Either way, flush it out real good with some water & "Prestone Radiator Flush" many times. Make sure you let the engine heat up with that stuff in it so it circulates good. Do this on dry ground so you can see what/if anything leaks.