Description

Mercury MerCruiser Quicksilver 861949T is a genuine OEM thermostat retainer used in MerCruiser big-block cooling-system assemblies. Current Mercury dealer and parts-diagram sources identify 861949T as RETAINER Thermostat / RETAINER-T STAT, and place it in the cooling system, fresh water components and closed cooling system sections rather than as a general hardware part.

Key Features

• Genuine Mercury MerCruiser OEM part number 861949T.
• Cataloged as RETAINER Thermostat / RETAINER-T STAT.
• Used in MerCruiser fresh-water and closed-cooling assemblies.
• Current dealer listing shows GTIN 745061476332.
• Current shipping-spec listing shows approximate packaged size of 4.50 x 3.00 x 0.65 in and weight of 0.30 lb.

Engine Compatibility

The strongest supportable fitment for 861949T is MerCruiser 496 MAG, 496 MAG HO, 496 MAG EC, 496 HO Bravo, 8.1L inboard, 8.1L HO inboard, and 8.1L Towsport applications shown in current Mercury dealer where-used references. Current parts diagrams also place it in the cooling-system assemblies for 8.1L / 496 CID MAG engines.

Serial Number Fitment Notice

Verify fitment by exact engine serial number and cooling-system diagram before ordering. Current Mercury where-used references show 861949T across multiple serial breaks within the 496 MAG and 8.1L families, so the safest match is the exact serial-based parts breakdown rather than engine family name alone.

When This Part Needs Replacement

This retainer is typically replaced when it is corroded, damaged, warped, or no longer secures the thermostat correctly during cooling-system service. Because 861949T sits in the thermostat and heat-exchanger area of the closed/fresh-water cooling layout, correct sealing pressure and proper fit matter more than appearance alone. This service guidance is a practical inference based on its documented thermostat-retainer role in the cooling assembly.

Installation Notes

Install 861949T only after confirming the correct MerCruiser cooling-system diagram for the engine being serviced. Current parts diagrams place it with the thermostat, thermostat seal, washers, screws, and heat exchanger in the fresh-water / closed-cooling section, so it should be matched against the exact assembly before service.

Alternate/Superseded Part Numbers

Current sources reviewed show 861949T as the active OEM Mercury number. The sources checked did not show a clearly supported newer superseding Mercury number for this retainer.

Parts Desk Insight

This is the kind of part that sounds generic until you look at the application. Matching 861949T to the exact 496 MAG / 8.1L cooling-system diagram is the safer move, because thermostat-area parts can look simple while still being specific to one crossover and heat-exchanger layout.

Shipping: Ships same or next day for fast Canada wide shipping.