Aston Martin DB9, DBS, Rapide & V12 Vantage Power Steering Pump: Noises, Leaks & Fluid Guide (2004-2019)

Symptoms of a Failing Power Steering Pump

A failing power steering pump on the Aston Martin DB9, DBS, Rapide, V12 Vantage, or Virage will provide several distinct warning signs. Because these issues can affect vehicle control, they should be addressed promptly.

Whining or Groaning Noises

This is the most common symptom of a power steering problem. You may hear a high-pitched whining or groaning sound that changes with engine speed (RPM). 🎬 Listen to what a failing power steering pump sounds like. The noise will often get louder when you turn the steering wheel. This sound is typically caused by one of two issues:

• Low Fluid Level: A leak in the system (from the pump, hoses, or reservoir) allows the fluid level to drop. When the pump sucks in air, a process called cavitation, it creates a loud whining noise. This is the pump being starved of fluid and protesting.
• Internal Pump Failure: If the whining noise persists even when the fluid reservoir is full, the bearings or internal vanes of the pump itself may be worn out and failing.

Some owners report this whining noise is only present when the engine is cold and disappears after a few minutes of driving. This often points to issues with old, incorrect fluid or the very early stages of pump wear.

Stiff or Heavy Steering

If turning the steering wheel, especially at low speeds or when parking, suddenly requires a lot of effort, it's a clear sign of failing power assistance. This can happen intermittently at first. You might find the steering is heavy at idle but feels normal once you're moving. This is a direct result of the pump not generating enough hydraulic pressure, either due to a leak, a slipping drive belt, or internal failure.

Fluid Leaks

If you see puddles of reddish-brown or green fluid under the front of your car, you likely have a power steering leak. While the leak could be from a hose or the reservoir, the pump itself has seals that can fail and leak over time. Running the pump with low fluid can quickly cause permanent damage, so any leak should be investigated immediately.

Steering Wheel Vibration or Jerkiness

A failing pump can deliver inconsistent pressure, causing the steering wheel to feel jerky or vibrate, especially when turning. In some cases, the steering may feel like it momentarily gets stuck, particularly when turning from the center position. This indicates a serious problem within the pump or steering rack.

Known Issues, TSBs, and Recalls

While there have been no specific NHTSA safety recalls for the power steering pump on these Aston Martin models, there is a critical Technical Service Bulletin (TSB) that every owner should be aware of.

TSB SB-11-0300: Steering Judder and Fluid Update

In April 2010, Aston Martin issued a bulletin to address complaints of a "squeak from the steering column" and a "judder" (vibration) during cold starts on early models. The problem was traced to the original Texaco Cold Climate power steering fluid.

• The Fix: The official procedure is to flush the entire system and refill with Pentosin CHF 11S synthetic hydraulic fluid, along with a 50ml bottle of Lubrizol friction modifier additive.
• Affected Vehicles: This TSB applies to specific VIN ranges, including the DB9 (up to VIN A12418) and DBS (up to VIN E01351). However, it is considered best practice to use Pentosin CHF 11S on all of these V12 models, even if the reservoir cap specifies ATF.
🎬 Watch this guide to choosing the correct fluid for your DB9.

Performing this fluid update can often resolve cold-start steering stiffness and noises without replacing any hardware.

Buying a Used Power Steering Pump

Given the high cost of a new OEM pump, a quality used OEM part is an excellent value. Because this part is shared across the DB9, DBS, Rapide, V12 Vantage, and Virage, there is a good supply of recycled units available. Here’s what to look for:

Physical Inspection

• Check the Pulley: Inspect the pulley for any cracks, chips, or bends. A bent pulley can cause belt issues and indicates the part may have been damaged during removal or in an accident. Ensure the pulley spins smoothly by hand with no grinding or excessive play.
• Inspect for Leaks: Look for signs of old fluid residue around the hose connections and the main shaft seal behind the pulley. While a part may be cleaned before sale, heavy staining can indicate a past leak.
• Examine the Housing: Check the aluminum pump housing for any cracks, especially around the mounting points.
• Hose Connections: Ensure the threaded ports for the high-pressure and low-pressure lines are clean and undamaged.

Compatibility and Part Numbers

• Verify the Part Number: The most common part number is 4G43-3A696-AD. You may also see earlier versions like 4G43-3A696-AC or the Rapide-specific AD43-3A696-AA. These are all functionally interchangeable for the 6.0L V12 engine.
• Mileage Consideration: Power steering pumps do not have a set lifespan and often fail due to fluid contamination or leaks rather than mileage alone. A used pump from a lower-mileage vehicle (under 80,000 miles) is preferable, but a well-maintained part from a higher-mileage car can still be a reliable option. The key is that the system it came from was properly maintained.

Replacement and Installation

Replacing the power steering pump is a moderately difficult job that can be performed by a skilled DIY mechanic. Access in the V12 engine bay is tight.

Key Procedures

• Access: On the DB9, access typically requires removing the engine slam panel and the throttle body assembly.
• System Flush: It is absolutely critical to flush the entire power steering system when replacing the pump. The old pump may have sent metal particles into the system, which will destroy the replacement pump and could damage the expensive steering rack.
🎬 See how to properly flush your power steering system.
• Bleeding the System: After installing the new pump and filling the reservoir with fresh Pentosin CHF 11S, you must bleed the air out. With the front wheels off the ground and the engine OFF, turn the steering wheel slowly from full lock to full lock at least 10 times. This circulates the fluid and purges air without risking damage to the new pump by running it dry. Top off the fluid as needed.

Cost of Replacement

Replacing the power steering pump on these Aston Martin models can be expensive, making a used OEM part a very attractive option.

Cost estimates are approximate and can vary based on location, supplier, and vehicle condition.

Frequently Asked Questions (FAQ)