I would not consider grapeseed oil a good candidate for high heat cooking.  Grapeseed oil contains 75% omega-6, which may be a potential health danger.  Too much omega-6 in the diet creates an imbalance that can interfere with production of important prostaglandins (a group of hormone-like substances that play a role in a wide variety of physiological processes). This disruption can result in increased tendency to form blood clots, inflammation, high blood pressure, irritation of the digestive tract, depressed immune function, sterility, cell proliferation, cancer and weight gain.

According to Mary Enig, PhD, one of the world's leading researchers on fats and oils, “Grapeseed oil contains phenols that raise the smoke point. However it is very high in omega-6 fatty acids, so it not a good choice for our diets–we need to avoid excess omega-6 fatty acids as much as possible. Also, grapeseed oil is industrially processed with hexane and other carcinogenic solvents, and traces will remain in the oil.”

Good quality grapeseed oil in small amounts can be used along with olive, walnut and avocado oil on salads, raw veggies and in dips, sauces and salsas. Mix it with garlic and basil and rub it into whole grain breads. Because it is a light oil, it holds flavors beautifully.

Grapeseed oil has excellent emulsification properties, which makes it ideal for salad dressings that do not cloud when chilled.  Like olive oil, grapeseed oil is best eaten unheated.  In it's unheated form, it can be an excellent healthy oil.