New Radiator Fitted / Low Coolant

[rick3000]

It sounds like the mechanic did not refill the coolant system properly. They should have refilled it by creating a vacuum, but it sounds like they just poured it in and the system has some air bubbles. The best DIY solution is to top it up (with the same coolant), remove the coolant and oil caps, pop the plastic cover off, and open the bleed valve (just flip the wire handle up), reinstall the caps, drive it for 2 days then close the valve, and put the cover back on.

While this isn't necessarily a huge issue, the mechanics careless raises a red flag because you want to avoid any unnecessary coolant issues. I 100% agree with Steve, you need to find out if he replaced the coolant (ideally after flushing with distilled water), refilled it with the old coolant, or topped it up with the same or different coolant. Mixing different coolants can cause them to gel in the system, which is obviously bad. I had a mechanic do this several years ago, then had to deal with several years of coolant issues before I figured it out and flushed the system.