Checking your automobiles fluids

Checking all the fluids in your car

Checking the automobile fluids on a regular basis is not only important, it is critical to the longevity of your engine as well as most other systems in your vehicle. The fluids we will talk about are the engine oil, transmission fluid, brake fluid, power steering fluid, coolant and differential fluid.  Please see our special section to air conditioning fluid (gas). We also feel that windshield wiper fluid is pretty self-explanatory!

Engine Oil

Engine oil and the additives in engine oil cools, cleans, lubricates, and moistens the seals on all internal engine parts. Clean engine oil is gold in color, while dirty engine oil is black, except in diesels where even clean oil is black. To get an accurate reading, check the engine oil when the engine is cold. Most engines hold between four and five quarts of oil. Vehicle manufacturers suggest adding oil when the engine is low one quart but unless your engine is burning oil, you should not usually need to add oil between oil changes.

To check the engine oil open the hood, and look for the engine oil dipstick. The engine oil dipstick is usually located on the side of the engine on rear-wheel drive vehicles or near the front of the engine on front-wheel drive vehicles. Check your owner’s manual if you have questions on the location of the dipstick. Important: when checking any fluid, it is important to park on a level surface. Pull out the dipstick, wipe it off with a rag, reinsert it completely into the tube, remove again, and check the levels. The oil should be in the safe range. To add engine oil, locate the oil filler cap on the valve cover of the engine. Use a funnel to add the correct amount. Give the engine oil time to flow to the oil pan. Recheck the level and keep adding but do not overfill.

Transmission Fluid

Automatic and manual transmissions have fluid which cools, cleans, lubricates, and seals internal components, just like engine oil.  Clean automatic transmission fluid is always a light red. Always refer to the manufacturer’s recommendations for the correct transmission fluid. There are not that many but the last thing you want to do is put the wrong kind in. We recommended checking the transmission fluid while it is hot. Drive your car about ten minutes to warm up the transmission. To receive accurate results, most manufacturers recommend that the engine still be running but PLEASE make sure the car is in Park! Also,apply the parking brake. Locate the automatic transmission oil dipstick. Warning" newer cars do not have accessable transmission fluid dipsticks.  They are "maintenance free". But, if you can have a little older car, with the engine idling, pull out the dipstick, wipe it off with a rag, reinsert it completely into the tube, remove again, and check the reading. The transmission fluid should be between the full cold and the full hot marks. If it is a bit low, use a clean funnel to add the necessary fluid by pouring the fluid directly into the dipstick tube. Do not overfill. It usually takes only one pint (½ quart) of fluid to bring the fluid level from the full cold to the full hot mark.

On manual transmissions there is usually a plug on the side of the transmission. To check the fluid level, you must turn the engine off, apply the parking brake, and remove the plug with a wrench, this is a big pain. The fluid should be at or near the bottom of the filler plug. Some manual transmissions actually take automatic transmission fluid), while others take heavyweight (SAE 80W90) gear oil. Check the owner’s manual for specifications. Fill as necessary.


Checking your automobile fluids requires checking the coolant (antifreeze). Coolant comes in a rainbow of colors: green, orange, red, pink, yellow, and blue green. The most common colors are however are green and orange. The standard coolant used in vehicles before 1995 was green. In 1995, General Motors started using an extended life coolant, called Dex-Cool. Dex-Cool was orange and was originally manufactured by Havoline just for General Motors. Today, several other coolant manufacturers produce extended life coolants. Both standard (green) antifreeze and Dex-Cool (orange) antifreeze are glycol based. The main difference between the two types of antifreeze is in the rust inhibitors and additives. Ethylene glycol, which is used in both standard and extended life coolants, is extremely toxic. When checking coolant levels, the engine must be cool. First, check the level in the coolant recovery tank. The recovery tank is usually semi clear with a full cold and a full hot mark. If adding fluid, remove the cap and add a 50% water to 50% antifreeze mixture. Second, check the level in the radiator. This requires removing a cool (DO NOT REMOVE A HOT CAP, YOUR FACE WILL GET BURNED ) radiator cap and looking into the radiator. The fluid should be at or near the top. Add a 50/50 mixture as needed. Reinstall the cap.

Brake Fluid

Brake fluid provides the transfer of hydraulic pressure to the wheels. This is what slows the car down, and this is the second most important process when checking your automobile fluids. Clean brake fluid is clear in color. Use extreme caution when handling brake fluid, it is toxic, can damae your eyes and can damae a cars finish in a bout five seconds.  The most common type of brake fluid is DOT 3, but always refer to your manufacturer’s recommendations. There is also DOT 4 and DOT 5. The brake master cylinder that houses the fluid is usually mounted on the driver’s side firewall in the engine compartment. Most vehicles today have a plastic clear reservoir with a “min” and “max” line. To add brake fluid, turn the engine off, remove the cap, and add as necessary. Wait for the fluid to drain a little and DO NOT OVERFILL!!!!  When reinstalling the cap, make sure that the rubber gasket seats properly OR TOXIC FLUID WILL BE ALL OVER THE CAR.

Differential Fluid

Rear and front differentials, which connect the drive shafts to the wheels, also require fluid. This fluid check is needed on rear-wheel drive or four-wheel drive vehicles, and is similar to checking manual transmission fluid. Remove the check plug, check the level, and fill as necessary. The oil should be at the bottom of the plug hole. Gear oil, which is very thick is the most common differential fluid. Some differentials use limited slip additives. Always check your owner’s manual for the specific fluid.

Power Steering Fluid

All vehicles today have power steering. When checking your automobile fluids power steering needs to be on your checklist. The power steering pump is located off an engine drive belt. The cap and the dipstick are commonly one unit. To check the fluid, shut off the engine, find the power steering reservoir, remove the dipstick, wipe it off, put it in again, remove again, and note the reading. The stick usually has a full hot and a full cold line. Using a clean funnel, add fluid as necessary. Power steering fluid can be clear, gold, or red. Check your owner’s manual for specifications.