99 SD missing coolant
Hello all. A few weeks ago I had my oil cooler replaced. It got to the point where the reservoir was full of a thick mix of oil and coolant. It was actually spilling out of the reservoir cap and made a mess on engine and pavement. After replacement the truck was driven moderately for about 1000 miles and all was good. Yesterday I drove about 230 highway miles and when I got home I noticed what looked to be oil dripping in about 4 to 5 spots when I parked on incline. I popped the hood and there was no antifreeze in resovoir. There was what looks and feels like oil/antifreeze puddled on intake manifold. The temp guage never jumped above normal the whole trip. Oil was at normal level and no signs of coolant. I have only had the truck for a couple months and it sits parked in same spot and have never seen an oil leak. Has anyone experienced anything like this? Thanks for any and all input.