I have a 1994 Toyota Pickup with about 270k on the odometer. I recently flushed my radiator like I do every three or four years. When I opened the hood today and popped open the radiator cap, I noticed that there was gel around the cap threads. This really bothers me. It might be nothing, but I want to make sure.
P.S. If it helps, I mixed O’reily brand and Prestone brand coolant. The Prestone said it was compatible with all colors.