What is power steering fluid made of

Last Updated August 31, 2021

You should check the power steering fluid on a monthly basis to see that it has the appropriate amount of fluid. Also, to see if the power system is functioning OK, and not leaking. Leakage can cause a lot of damage to the rest of the system. Luckily, the reservoirs on many cars are see-through, so it’s easy to check.

You should be careful when choosing a substitute because by using the wrong type of fluid, you could cause damage. Incompatible fluids could attack the seals, plastic and rubber parts. Furthermore, it could have a bad reaction with the remains of the original fluid, producing acidic substances.

Power steering fluid is a thick reddish or brownish liquid. Most power steering fluids are silicone-based fluids or mineral oil. But, some use automatic transmission fluid (ATF). ATF is made from synthetic base oil. In an emergency, there are some power steering fluid substitutes you can use, at least until you can get a hold of the appropriate fluid for your car.

Safe Power Steering Fluid Options

Now, just because you CAN use something, doesn’t necessarily mean that you SHOULD use it. If you were to use a brake fluid, you would probably do more harm than good to your car. Why? Because it has a different chemical makeup:

• 60-90% solvent
• 5-30% lubricant
• 2-5% additives

Brake fluids today are mostly glycol-ether based, but there are also mineral oil and silicone-based fluids available.

The most commonly used power steering fluid substitute is automatic transmission fluid (ATF). Actually, a lot of manufacturers use ATF instead of power steering fluid. It consists of:

• 85-90% base oil
• 10-15% additives

The process of selecting a compatible automatic transmission fluid can be tricky. Using the wrong type can cause damage to the transmission. Each automatic transmission fluid has a specific viscosity, friction coefficient, and additives, so they all differ. They are all manufactured by petroleum companies in accordance with recipes of base oils and additives.

Automatic Transmission Fluids

There are several types of transmission fluids you can consider, and these are the best ones:

Dexron

This is a transmission fluid with a greenish, greyish or brownish color. Originally, the Dexron fluid used sperm whale oil as a friction modifier. Importing sperm whale oil was banned later on which meant it had to be reformulated. It has a green, grey or brown coloring which differs from the red and purple coloring of ATF. There are now variations on Dexron transmission fluid: Dexron II, Dexron IID and Dexron IIE, Dexron G, Dexron III G, Dexron III H, Dexron IV, Dexron VI

2. Mercon

There are also variations on this type of fluid: Mercon CJ, Mercon H, Mercon Ford, Mercon V, Mercon SP.

A number of auto manufacturers adapted Mercon and Dexron as the specification for their automatic transmission. Their similarities make them interchangeable. There have also been many variations of these two fluids.

One common problem is that oil companies started to claim that these fluids could be used on a whole list of vehicles manufactured by companies other than Ford and General Motors. Needless to say, be wary of multi-vehicle ATFs.

Other ATFs

Naturally, there were other automatic transmission fluids before Dexron and Mercon:

1. Type A

Introduced in the 1950’s and was used on all automatic transmissions for GM vehicles. This fluid was used through the mid-1960’s.

2. Type F

It’s quite an old fluid, made for Fords using bronze clutches. This fluid would only be useful on classic or antique cars.

3. HFM Fluids

(Highly friction modified), have different characteristics related to friction in contrast to Dexron and Mercon.

The Verdict

The best power steering fluid substitute and the safest one is automatic transmission fluid. Your best bet is ATF when you’re out of power steering fluid. But bear in mind, nothing works better than the fluid made for power steering. If you’re in need, you’re in luck, most if not all power steering fluid is budget friendly.

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