I need some advice.
I have an '04 4.0 Sport, so this Head Gasket thing has always been in the back of my mind.
I have 230,000 miles and noticed something weird last week:
I have no could of smoke on startup. No waterfall sound. No CEL or codes.
What I do have is a black layer of crud that appeared of the inside of the overflow reservoir/tank of my radiator above the coolant, on the walls (probably 40k - 60k miles and 3.5-4 years on that radiator) I lost a little fluid in there, but it came back 2 days later. That was a week ago. I lost a little fluid again today. The black crud isn't in the fluid, only on the walls above the fluid. The fluid is 3.5-4 years old too, since the new radiator. I read that you should take the reservoir off, scrub it with dish soap, and replace it, and see if the black goo comes back. Only problem is that everyone that has a HG failure has the black goo in the fluid. This black crap looks terrible on the walls of the reservoir.
Should I get a hydrocarbon test? Oil is looking good on the dipstick, no condensation or anything on the cap. I just switched to synthetic 0w-20 on my last oil change, also.
Thoughts????