Find coolant, refill and get moving again
Get the full Coolant jug from the starting house, or use water, then pour your chosen liquid into the radiator without mixing them. If the engine has overheated, leave it off to cool, restore the radiator's liquid supply and check whether the engine also needs repair.
Where to find coolant and water
The starting house supplies a full 5 L Coolant jug, and common chests can contain more. Other Coolant jugs you find may be only partly full, so check their contents before relying on them. Early Access includes this coolant item; the older demo had no coolant container.
Water comes in bottles, jugs and buckets found along the road, and those containers are not always full. You can pour water between containers to gather your supply together. Keep a drinking reserve separate from what you intend to spend on the radiator.
You can also collect rainwater by leaving an empty Bucket or Mug upright outside under open sky. A container you are holding, carrying in your hotbar or backpack, sheltering beneath a roof, or using for another drink will not fill. Heavier rain fills it faster, making a rainy stop a useful chance to replenish your water.
Choose the liquid you will keep using
Use coolant when you have it: it cools better and is consumed half as fast as water. Water still works and completes the radiator-filling objective, so you do not need to wait for another Coolant jug. Once you choose a liquid, keep that same kind available for top-ups because water and coolant cannot be poured on top of each other.
How much liquid your radiator holds
| Radiator | Full capacity |
|---|---|
| Radiator I | 6 L |
| Radiator II | 12 L |
| Radiator III | 18 L |
A full 5 L Coolant jug does not completely fill an empty 6 L Radiator I, so bring more coolant for the remaining space. The radiator-filling objective completes at 2 L, before the radiator is full. Treat that tick as objective progress and keep filling with the same liquid before a longer drive.
How to fill or top up the radiator
- Fit a radiator if yours is missing. A missing radiator provides no radiator cooling, and newly found radiators need filling because they start empty.
- Check which liquid is already inside the radiator. A water-filled radiator needs more water, while a coolant-filled radiator needs more coolant.
- Pick up a container holding the matching liquid. Use the dedicated Coolant jug for coolant, or a water-filled Water Jug, Bucket, Coffee Pot, Bottle of Water or Mug for water.
- Pour from the held container into the radiator at the RV. Either water or coolant contributes to the radiator-filling objective.
- Continue filling with the same liquid until the radiator is full. The objective can finish earlier, so check the actual level before setting off.
- Keep a matching refill supply in the RV. Radiator liquid is consumed while the engine runs, so you will need to maintain the supply during your trip.
Why liquid will not go into the radiator
Check the contents of the container before trying to pour again. Buckets, Coffee Pots, Bottles of Water and Mugs can carry different liquids, so their names do not guarantee that they contain water. A Jerrycan holds only gasoline and cannot carry a radiator refill.
The radiator refuses milk, coffee, gasoline and oil. It also refuses coolant added to water, or water added to coolant. To switch between the accepted liquids, drain the radiator completely before filling it with the replacement.
Recover from overheating and check for damage
Read the dashboard warning before choosing a repair. An empty radiator provides no radiator cooling, just like a missing radiator, while a broken radiator needs attention to the part itself. An overheated engine and a broken engine also require different fixes.
- Leave an overheated engine off until it cools. The engine shuts down at heat 95, and the ignition allows restarting after heat falls to 55.
- Top up a low or empty radiator with its existing liquid type. Restoring the supply addresses the cooling shortage before you continue driving.
- Replace the radiator if the dashboard says "Radiator is broken". That warning identifies a damaged part; "Radiator is out of coolant" identifies the liquid supply instead.
- Use an Engine Repair Kit or fit another engine if the ignition says "Engine is broken". A broken engine will not restart until repaired, even after it has cooled.
- Try the ignition again after fixing the reported problem. More than one fault can apply, so address any remaining battery or fuel warning and check again.
Engine condition starts falling above heat 85, with faster wear as heat rises. Repeated overheating can therefore leave you needing engine repairs after the radiator has been refilled. Keep cooling down, restoring radiator liquid and repairing engine condition as separate checks.