Replenish Your Car's Fluids

SKILL LEVEL 1

Gallons of fluid course through your car's systems, keeping them cool and lubricated so your car doesn't die when you're en route to an important job interview. And yet, many motorists don't take the few minutes needed to check car fluid levels and top them off. Don't be one of them — here's what to check and what to do if levels are low.

1 Skill level
1 out of 5
8 Steps
9 Materials

Step 1 Engine oil

Oil lubricates your engine's moving parts, decreasing the friction between them.
Check the oil every time you fill the gas tank. Locate the oil dipstick, which is usually at the front of the engine and has a brightly colored handle. Pull it out of the tube and inspect the oil. If it’s dark brown or black instead of a golden honey color, it's time for an oil change.
Wipe the dipstick clean with a rag. Insert it all the way back into the tube, wait a few seconds and pull it out again. The oil level on the dipstick should be at least halfway between the Add Oil and Full marks.
If the oil is low, add the same brand and weight of oil that's already in the engine. Add a little bit at a time through the oil filler on top of the engine. Recheck the level each time and stop when the level is at, but not above, the Full mark.
Step 2 Antifreeze

Antifreeze keeps the water that cools the engine from boiling or freezing.
When checking the level, don't remove the radiator pressure cap — instead, check the coolant level at the surge tank reservoir. The correct level depends on whether the engine is hot or cold.
If the coolant level is low, add a 50-50 mix of water and antifreeze. Never add plain water or pure antifreeze. Antifreeze premixed with water may be identified as “antifreeze coolant” on the label; use it straight from the container.
Step 3 Brake fluid

Brake fluid applies hydraulic pressure to the brake calipers.
The brake master cylinder is on the firewall behind the engine. Most cars now have a translucent reservoir so you can easily see the fluid level. Otherwise, wipe dust and dirt off the filler cap on the master cylinder and remove it. Check the owner’s manual or the information on the cap to determine the correct fluid level — generally, the reservoir should be at least 2/3 full.
If the fluid is low, add the right kind: most cars and light trucks take DOT (Department of Transportation) 3 or DOT 4 fluid. Never add DOT 5 (silicone-base) fluid to a system that contains DOT 3 or 4 fluid; they're incompatible. Brake fluid absorbs moisture, so always add fresh fluid from a sealed can. Be careful pouring brake fluid, because it can damage your car's paint.
Step 4 Clutch fluid

The clutch on a manual-transmission car might be hydraulically operated. The clutch master cylinder is mounted on the firewall and is serviced like the brake master cylinder, above. In some cases, the same reservoir serves both brakes and clutch.
Step 5 Automatic transmission fluid

Transmission fluid lubricates and cools the moving parts of your automatic transmission. It also transmits power from the transmission to the engine
Locate the transmission dipstick under the hood. It probably looks much like the engine oil dipstick. If your car doesn’t have a transmission dipstick, checking the transmission fluid is a more complex project; refer to your car’s service manual.
If there is a dipstick, set the parking brake and start the engine. Move the transmission selector through all the gear positions, and leave it in park or neutral with the engine idling. Pull the dipstick out of the tube, wipe it clean and reinsert it into the tube. Pull it out again and check the level between the markings on the dipstick.
If the fluid is dark or smells burnt, have your mechanic check it. If low, add transmission fluid that meets the manufacturer’s specifications a little at a time through the dipstick tube, using a funnel. After you add a little fluid, wait a minute or so, and check the level again. Continue until the level is correct.
Step 6 Power steering fluid

Clean the top of the reservoir and remove the cap. Check the fluid level on the dipstick built into the cap. Fill to the correct level with the fluid specified on the reservoir cap or in the owner’s manual, usually either Dexron automatic transmission fluid or universal power-steering fluid.
Step 7 Windshield washer fluid

Washer fluid gets the top layer of gunk off your windshield until you have a chance to give it a proper washing.
Fill the windshield washer reservoir to capacity with premixed fluid. Pour it in full-strength for better cleaning in the summer and to prevent freezing in the winter.
Step 8 Battery

Most new batteries are maintenance-free; you can’t even remove the cell caps. If that’s what's in your car, leave it alone.
If your battery has removable cell caps, the fluid level must be above the tops of the plates inside the cells. The fluid level is visible through the translucent case on many batteries, which makes checking easy if you can see the side of the battery. If not, or if the battery case is opaque, remove the cell caps and look into each hole. If the fluid isn't even with the ring at the bottom of the hole, add enough distilled water to bring the level to the ring.