I just followed this process and still have a lot of air pockets in my coolant. I noticed once I shut off the engine and popped the radiator cap off there was bubbling in the overflow box. I may have gotten a half gallon of juice in her.

Quote Originally Posted by Y33TREKker View Post
Did you try replacing the radiator cap along with all of the other items you mentioned, (or did the new radiator include one?). If the cooling system isn't kept properly pressurized, all of the hot coolant from the system will simply rise quickly to the top of the radiator because it's boiling. A properly functioning radiator cap that keeps the system pressurized will keep all of the coolant in a liquid state though.

It's also important to ensure that no air pockets formed during the coolant filling process.

  • Fill the coolant slowly with the engine off
  • When the radiator is full, then fill the reservoir to the "Max" mark
  • Install and tighten radiator cap
  • Idle engine for 2 to 3 minutes
  • Stop engine, reopen radiator cap (Carefully!! Hot!!, and refill coolant level if low
  • Tighten radiator cap and warm up engine at about 2000 rpm
  • Set heater to highest temperature position to allow coolant to circulate into the heater water system
  • Make sure thermostat is operating (radiator hoses should get hot)
  • Idle engine for 5 minutes, then shut off
  • Allow engine to cool, remove radiator cap, and refill coolant level if necessary

I don't know if I've ever seen a fitting on or near the thermostat housings on a VX that allow a person to burp the cooling system when adding coolant (the engine on my car has one), but if a cooling system is filled too quickly and air pockets form in the cooling passages, overheating can occur. That possibility and a faulty radiator cap are my first two guesses anyway.