'97 FZJ80. Spark plugs look good. Going to do compression test next. I rebuilt the motor 17,250 miles ago. Noticed the white milkshake in the radiator today after adding 3/4 gal of water, and also under oil cap. Been noticing coolant loss in the last 3 or 4 weeks. No milkshake until today. 943 miles ago was my last oil change and oil came out looking normal then. Still running smooth. What else could be the problem besides head gasket; oil cooler? O ring in the timing chain cover? Spark plugs 1 through 6 from top to bottom.