Checking and Adding Liquid to a Coolant Recovery System
Tip: Many vehicles have a pressurized coolant recovery system called an expansion tank that makes opening the radiator unnecessary. These systems are considered "sealed" because the safety pressure cap is on the recovery reservoir rather than on the radiator. On these systems, you can check the level of liquid on the side of the plastic reservoir, and you just open the cap on the reservoir to check whether the coolant looks as though it needs changing or to add water and coolant.
You will probably never need to open the cap on the radiator, but if you have to open the cap for any reason, make sure to fill the radiator to the top with a 50/50 mixture of coolant and water before replacing the cap. This addition bleeds the system by forcing any air that may have gotten into the system into the reservoir and out through its overflow pipe when the engine heats up. Follow these steps when adding liquid to the coolant recovery system:
- Check the liquid level. Look at the outside of the reservoir to see where the level of the liquid in it lies relative to the "MAX" and "MIN" lines embossed on the side (refer to Figure 12-1).
- If the liquid level is low, add equal parts coolant and water to the reservoir.
Checking and adding liquid to a radiator
If you don't have a pressurized coolant recovery system, you have to add liquid directly to the radiator. Here's how:
- Open the radiator cap.
- Take a peek down the radiator fill hole to see how high the liquid level is inside. If you're unsure about what the liquid level should be, just make sure that it covers the radiator tubes that are visible when you look down the hole, or that it reaches to within a couple of inches below the cap.
- Add water and coolant, or pre-diluted coolant, as necessary.
- When you finish, replace the cap by screwing it on clockwise. (If youhave a safety pressure cap, push the lever down again.)
From Auto Repair for Dummies, copyright © 2009 by Wiley Publishing, Inc., Indianapolis, Indiana. Used by arrangement with John Wiley & Sons, Inc.