Power Trim & Steering Fluid 32 oz. | Sierra 18-9751-2

Sierra 18-9751-2 Power Trim & Steering Fluid | 32 oz. (1 Quart) | Marine Power Tilt, Trim & Power Steering | Replaces Mercury 92-858075K01

The Sierra #18-9751-2 is a 32 oz. (1 quart) power trim and steering fluid formulated for marine power tilt, power trim, and power steering hydraulic systems. Protects seals, hoses, and internal components. Mixes freely with existing fluid for top-offs without draining the system. Replaces Mercury 92-858075K01. Not recommended for systems that specify SAE 0W-30 oil.

Product Details:

• Part Number: 18-9751-2 (Sierra)
• SKU: SIERRA-18-9751-2
• Manufacturer: Sierra
• Type: Power Trim & Steering Fluid
• Size: 32 oz. (1 quart)
• Application: Marine power tilt, power trim, and power steering hydraulic systems
• Compatibility: Mixes with existing fluid — suitable for top-offs
• Exclusion: Not for systems specifying SAE 0W-30 oil
• Replaces: Mercury 92-858075K01

Cross-Reference — Replaces:

• Mercury: 92-858075K01

Additional Information

SAE 0W-30 Exclusion — Critical Compatibility Note:

The Sierra 18-9751-2 is not recommended for power trim or power steering systems that specify SAE 0W-30 engine oil as the hydraulic fluid. Some MerCruiser and Mercury Marine power steering and trim systems — particularly newer or higher-specification models — specify SAE 0W-30 engine oil rather than a dedicated power trim fluid. Using the wrong fluid type in these systems can cause seal swelling, pump damage, or erratic system behavior. Before topping off or refilling, confirm the fluid type specified for your system in the engine or sterndrive service manual. If your system specifies SAE 0W-30, use that specification instead of this product.

Marine Power Tilt, Trim & Power Steering — Three System Types:

The 18-9751-2 is formulated for three distinct marine hydraulic systems that share similar fluid specifications:

• Power tilt — the hydraulic system that raises the outboard or sterndrive out of the water for trailering or storage; operates at lower pressure than power trim
• Power trim — the hydraulic system that adjusts the running trim angle of the drive or outboard while underway; operates across a wider pressure range
• Power steering — the hydraulic assist system on inboard and sterndrive applications that reduces steering effort at the helm

Confirm your system type is covered by the 18-9751-2 specification before ordering.

Mixes with Existing Fluid — Suitable for Top-Offs:

The 18-9751-2 is compatible with existing power trim and steering fluid already in the system and can be added directly for top-offs without draining and refilling. This makes it practical for maintaining fluid level between full fluid changes. If the existing fluid in the system is unknown or contaminated, drain and refill completely rather than topping off with the 18-9751-2.

Seal and Component Protection:

The fluid is formulated to condition and protect the seals, O-rings, and hoses in the power trim and steering hydraulic circuit, preventing drying, cracking, and corrosion of internal components. Marine hydraulic systems are exposed to the corrosive marine environment through vents and reservoir openings — a properly formulated fluid with seal conditioners extends the service life of pump seals and hydraulic cylinder seals between overhauls.

Mercury Cross-Reference — 92-858075K01:

The Sierra 18-9751-2 replaces Mercury Marine 92-858075K01 — the OEM Mercury power trim and steering fluid. If your service manual or parts list references this Mercury part number, the Sierra 18-9751-2 is the correct aftermarket equivalent.

Fluid Level Check — Inspection Interval:

Check power trim and power steering fluid levels at the beginning of each season and whenever trim or steering performance changes. Symptoms of low fluid include:

• Slow or sluggish trim response — drive or outboard moves slower than normal through the trim range
• Trim system not holding position — drive creeps up or down under load
• Increased steering effort at the helm — power steering assist reduced
• Fluid visible at hose connections, reservoir cap, or cylinder seals — indicates a leak that should be repaired before topping off

Installation Notes:

• Confirm your system does not specify SAE 0W-30 oil before using this fluid
• Check service manual for correct fluid specification for your specific power trim and steering model
• Add directly to reservoir for top-offs — do not overfill beyond the full mark
• If fluid is discolored, foamy, or contaminated, drain and refill completely rather than topping off
• Inspect hose connections and cylinder seals for leaks if fluid level is consistently low

Frequently Asked Questions

1. Why can't I use this fluid in systems that specify SAE 0W-30?
Some Mercury Marine and MerCruiser power trim and steering systems specify SAE 0W-30 engine oil as the hydraulic fluid rather than a dedicated trim fluid. Using the wrong fluid type can cause seal incompatibility, pump damage, or erratic operation. Always confirm the fluid specification in your service manual before adding fluid.

2. Can I mix this fluid with what's already in my system?
Yes — the 18-9751-2 mixes freely with existing compatible power trim and steering fluid for top-offs. If the existing fluid is unknown, contaminated, or a different specification, drain and refill completely.

3. What Mercury Marine part number does this replace?
Mercury 92-858075K01.

4. How do I know if my power trim fluid is low?
Symptoms include slow trim response, trim not holding position under load, or increased steering effort. Check the reservoir fluid level at the sight glass or dipstick per your service manual's procedure.

5. Does this fluid work for power steering on inboard sterndrive applications?
Yes — the 18-9751-2 covers marine power steering systems in addition to power tilt and trim, provided the system does not specify SAE 0W-30 oil. Confirm against your service manual's fluid specification.