Sounds like your engine is not fully warming up. Also, the type of oil you use can contribute to the yellow gunk, Quaker State oil used to be bad for that. But, it would now be a good idea to flush your oil system, put in according to the can, some Seafoam into the oil, and run it for about 50 to 100 miles and drain the oil and change the filter. Put in some cheap oil along with half as much Seafoam as before, and run another 50 to 100 miles and change again to what you would regularly run. The system should now be clean, and if you clean the PCV system and the box, and make sure you run the engine for more than 5 minutes, hopefully it won't be a problem.