It very well could be a more serious problem, but check underneath first.
I lucked out last week and was told that I had picked up a plastic bag while driving and it had wrapped itself around my muffler and had been slowly burning for about a week.
5w/filter
The oil pressure switch on a 1989 Chevy Camaro RS is located on the bottom of the engine hear the oil filter. It constantly monitors oil pressure and updates the computer on its status.
85W90 Gear oil.
1989 Chevy s10
10w30 unless it is burning oil, in that case use 10w40.
The oil capacity for a 1989 Chevrolet C 1500 truck is approximately 5.5 quarts of oil. The recommended oil type is 10 W 30.
It is inside of the oil pan and the oil pan is bolted to the bottom of the engine.
85w90 will be just fine.
You will need to drain the oil from your 1989 Chevrolet 5.7 liter engine oil pan. Remove the oil pan bolts. The oil pan will come off.
Any time you have water/coolant in your oil, look for a malfunction in your cooling system. A cracked head is a great place to start.
5 QTS. with new filter.
It is normal for the oil pressure to drop when the engine is warmed up and at an idle.