How to check or add power steering fluid on a Mercedes-Benz

Last updated: October 29, 2026

In this guide (6 sections)

1. Steps to check and add power steering fluid
2. What kind of power steering fluid should I use on a Mercedes-Benz?
3. Reading the dipstick so the number means something
4. Symptoms of Power Steering Problems
5. Applicable Models Applicable Years
6. Power Steering Fluid FAQ

Do you hear a loud whine when you turn the steering wheel of your Mercedes-Benz? This is most noticeable when starting the car or when the engine is cold, typically due to low power steering fluid. Not only is this embarrassing, but if the power steering fluid level is low, you should add fluid as soon as possible to avoid problems with the power steering pump. This can happen on any Mercedes-Benz model, including the E, C, S, CL, SLK, ML and CLK classes.

Watch: Mercedes S-Class W221: Check and Add Power Steering Fluid

Follow the step by step directions below to learn how to check the power steering level on your Mercedes-Benz or add new fluid.

Required Power Steering Fluid

• Mercedes-Benz Power Steering Fluid (Check Price Online)

Before you start

• Park your Mercedes-Benz on a level surface.
• Set the emergency brakes.
• Choose the correct power steering fluid for your car.

Steps to check and add power steering fluid

	STEP 1: Start the car and wait until it reaches the average operating temperature. This can take several minutes. Turn the steering wheel from lock to lock a couple of times. Next, open the hood by pulling on the hood release.
	STEP 2: Locate the power steering reservoir. Clean the reservoir cap with a clean cloth to avoid debris falling in.
	STEP 3: Remove the reservoir cap by twisting the cap counterclockwise. If you can’t remove the cap quickly, you may find removing the engine air tube easier. As you pull the cap, have a rag in hand to wipe off the dipstick. Be careful not to let any contaminants get into the reservoir.
	STEP 4: Reinstall the cap on the reservoir. Remove the cap again and check the fluid level on the dipstick. If the level is below the minimum mark, add power steering fluid to bring it up, but be careful to stay under the maximum mark. DO NOT overfill the power steering reservoir beyond the High/Max mark. If you add too much, draw the excess back out with a fluid transfer pump. Once you have the correct level, reinstall the cap and take the car for a spin. Ensure you don’t hear any whining or groaning from the power steering. Double-check the power steering level to ensure it is correct. If your car is at operating temperature, check the fluid level at the upper Max and Min marks on the dipstick, indicated by the 80°C writing. If your engine is cold, check the fluid level at the lower marks on the dipstick, Max/Min at the 20°C range.

What kind of power steering fluid should I use on a Mercedes-Benz?

Always verify with your dealer or look up the type of power steering fluid you should use on your car on your owner’s manual. In most models, Mercedes-Benz uses Pentosin CHF 11S fluid. Pentosin power steering fluid is sold at dealerships, but you can buy it for less online.
Check Prices: Find Genuine Mercedes Benz Power Steering Fluid

Reading the dipstick so the number means something

Most wrong readings on these cars come from reading at the wrong moment rather than from a faulty gauge. The cap dipstick carries two pairs of marks, one pair for a cold engine and one for a warm one, and the two pairs sit at different heights because the fluid expands as it warms. Step 1 above has you bring the car to temperature and turn the wheel lock to lock, which is what puts the fluid where the warm marks assume it is, so read against the warm pair if you have done that and the cold pair only on a car that has been standing.

Park level, wipe the dipstick on the way out, dip it once and read it straight away. A dipstick that has been sitting in the reservoir with the cap screwed down will show fluid up the stick from splash rather than level, which is how a system that is actually low reads full. If two consecutive readings disagree, trust the second one taken after a wipe.

Why the maximum mark matters. The warning above against overfilling is worth a reason. The reservoir has to leave room for the fluid to expand once everything is hot, and a reservoir filled past the upper mark pushes the surplus out through the cap vent as it warms. That ends up down the side of the engine and onto the belt, which is both a mess to find later and a belt that can start slipping. If you have gone over, take the excess out rather than leaving it to find its own way out.

On using a generic fluid in an emergency. The FAQ below is right that running the pump dry is worse than putting in whatever is to hand, and if you are stuck that is the call to make. Treat it as getting home, not as a repair: the system is designed around the fluid specification the manual names, and the sensible follow up is to flush back to the correct fluid rather than leaving a mixture in there indefinitely. Note what went in, so whoever flushes it knows what they are dealing with.

Symptoms of Power Steering Problems

The power steering pump typically warns you with an audible noise when it is low on fluid. Here are the top signs of low power steering fluid or pump failure.

Whining or Groaning Noise

Groaning noises are annoying; you can not ignore them quickly, even if you want to. You may initially hear the noise when you turn the steering wheel ultimately. As the fluid level lowers, you will hear the groaning almost every time you turn the steering wheel.

Adding power steering fluid to correct the level typically fixes the groaning noise. If it doesn’t, the power steering pump may need to be replaced.

Squealing Noise

If your car’s power steering makes squeaking noises when you turn on the engine, it’s a sign that the power steering belt may be old or the power steering pump is malfunctioning. Before you replace the pump, change the serpentine/power steering belt. It is cheaper, and in most cases, it will fix the squeaking noises that you hear in the morning.

The steering wheel is stiff.

If the power steering wheel is stiff when turned or requires a lot of force, it is a sign that the power steering pump is not producing the necessary flow to operate the power steering system. Have the car checked. You don’t want to lose power steering when driving. If you do lose the power steering, it will be challenging to turn the steering. You will have heavy steering.

Applicable Models Applicable Years

A Class		1997-2004	A160 CDI	A180 CDI	A200 CDI	A170	A200
C-Class	W 203	2000-2007				C 320	C 350
	W 204	2008-2014	C 250	C 300	C 350	C 63 AMG	C 55 AMG
E Class	W210	E 430	E 300 E320	E230	E 280	E 320	E550
	W211	E 200	E 250	E 300	E350	E 500	E63
S-CLASS	W 140	1993-1999	500 SEC	600 SEC	S 500	S 600	CL 500
	W 220	2000-2006	S 350	S 430	S 500	S 600	S 55
	W 221	2006-2013	S 550	S 600	S 63 AMG
	W 222
CLS-CLASS	W 219	2005-2011	CLS 500	CLS 550	CLS 55 AMG		CLS 63 AMG
	W 218	2012-Present	CLS 250 CDI	CLS 350 CDI	CLS 300	CLS 350	CLS 550
CLK-CLASS							CLK 63 AMG
	208	1998-2003	CLK 320	CLK 350	CLK 500	CLK 550	CLK 55 AMG
CL Class	W 215	2000-2006	CL 500	CL 600	CL 55 AMG	CL 65 AMG
	W 216		CL 550	CL 600	CL 63 AMG	CL 65 AMG
SLK	R 170	1998-2004	SLK 230	SLK 320	SLK 32 AMG
	R 171	2005-2009	R171	SLK 280	SLK 350	SLK 55 AMG
SL	129	1990-2002	300 SL	500 SL	SL 320	SL 500	SL 600
	R 230	2002-2012	SL350	SL500	SL55 AMG	SL600	SL65 AMG
	R 231	2013-Present	SL350	SL400	SL550	SL63 AMG	SL65 AMG
R-CLASS	V 251	2006-2009	R320 CDI	R 320 BLUETEC	R 350	R 500	R 63 AMG
M-CLASS	W163	1998-2005	ML 320	ML 350	ML 430	ML 500	ML 55 AMG
	W164	2006-2011	ML 320 CDI	ML 320 BLUETEC	ML 350	ML 500	ML 550
	W166	2012-Present	ML350	ML400	ML550	ML63 AMG	ML250 Diesel
GL-CLASS	X164	2007-2012	GL320	GL350	GL450	GL550
	X166
G-CLASS	W463	1978-2009	G 290	G 300 D	G 320	G 350	G 500

Power Steering Fluid FAQ

Should I continue to drive if my power steering fluid is low?

Avoid driving your Mercedes-Benz (C, S, SLK, CLK, M, E-Class) with low power steering fluid. Using a generic Power Steering Fluid is better than driving with very little power steering fluid in your power steering pump. You can also perform a power steering flush to replace all of the old fluid from the system.

How often should I replace the power steering fluid on a Mercedes-Benz?

You can always check with the dealer for the exact interval to replace the power steering fluid. Our recommendation is to change it every three years or every 75,000 miles.

How much does a power steering fluid change cost on a Mercedes-Benz?

The price to replace the power steering fluid could vary depending on the Mercedes-Benz model and your location. If you have a repair shop perform, the flush expects to pay between $110 and $240.

Why should I change the power steering fluid?

You should consider replacing the power steering fluid because it breaks down and becomes contaminated with metal and rubber particles. This can increase the wear rate of the pump and steering components.

Why do I lose power steering fluid?

As the car ages, the power steering seals will wear. If you only have to top off the power steering every other year, you are ok. If you have to add power steering fluid every month, you should have the system checked out and repaired or replaced. Unfortunately, power steering leaks can end up being expensive repairs.