Well looks to me like you have air in the cooling system.
How to bleed air from cooling system after a flush or repair. Set heater for maximum heat, Fill coolant reservoir to MAX mark with 50/50 water and coolant mixture. Loosen bleed bolt and fill radiator up to base of filler neck. Close bleed bolt when coolant flows out without bubbles. Tighten bleed bolt. With radiator cap removed, start and operate engine to normal operating temperature. Add coolant if necessary and check for leaks
The radiator should end up about full to the top of the chamber, or to the bottom of the cap. And the overflow bottle between MIN and MAX marks.
Keep an eye on the level for a couple days afterwards.
Anyhow ask them to check the compression test on all cylinders to see if the head its not an issue in the overheat problem and also advise them to "purge" the cooling system.
Let us know!
Monday, October 15th, 2007 AT 8:40 AM