I went to check the fluid level of the radiator on my '98 S-10 pickup and noticed that the water/coolant was black.Yes BLACK.Not brown or orange but BLACK.
I was going to flush the system includind the block but was wanting to know one thing. Should I replace the coolant with Dexcool or can I use standard coolant?
The truck has 168,000 miles on it and going strong.I purchased it with 160,000.When my duh huh ex-mechanic serviced the truck,he never mentioned that coolant. I assume he was tired or in a hurry.
Lat dollar spent there.
Any suggestions on the coolant would be helpful.

P.S. I have read all the good and bad about dexcool and I can't decide.