questions regarding fluids

I have two questions regarding engine fluids. First, I have two gallons of Toyota red coolant that are about 5 years old, but still are in the foil sealed containers. Do you think they are still OK to use? Second, my daughter just bought a 2011 Nissan Juke with a turbocharged engine. The owners manual calls for conventional oil, but I have been told that a turbo motor should use synthetic oil. Any comments about this would be appreciated. Also, if synthetic oil is used, any opinions as to the best brand (Mobil 1, Castrol Syntec, etc.)? Thanks for taking the time to address my questions. My best to all.


Wrench. I help when I can
Coolant will react to oxygen and heat. Oxygen will oxidize and cause it to go acidic. Heat will cause it to do like caramel in a frying pan over time. If these were kept sealed even for ten years. I would use em, as long as the product still meets OEM requirements.

In any engine, I really highly recommend going synthetic. In a turbo engine, I most definitely recommend synthetic. For the price and for the type of car you are describing, no use paying for Mobil 1 (this oil is used in new corvettes, camaros and porches etcetera), go Castrol or Valvoline. This will greatly enhance the longevity of the internals in any engine, so a 100K rpm spinning turbo can only be enhanced by a quality oil. This is the key to any engine. Want it to last? Go synthetic. Well worth the cost considering you will step down your oil change intervals of 1500miles or so. The added investment at first will catch up in the end and you get for sure an added 100k miles out of that engine barring nothing dramatic happens.
Thanks for the reply. I've been wrenching for 44 years, but I never owned a turbo car. I will be going the Castrol Synthetic route from now on, for all my vehicles, whether turbo or not. Thanks again, FrankF.