Mercury Quicksilver Circulating Water Pump Gasket 879150138 | MerCruiser 3.0L
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Mercury Quicksilver Circulating Water Pump Gasket 879150138
Part Number: 879150138 | Also listed as: 27-879150138
Brand: Mercury / Quicksilver
Official Product Type: Circulating Water Pump Gasket — OEM Cooling System Seal
Supersedes: 27-810848
System: Engine Cooling (Closed / Circulating Cooling Circuit)
A genuine OEM Mercury gasket that seals the mating surface between the circulating water pump housing and the engine block or front cover on applicable MerCruiser engines. Replacing this gasket at every pump service prevents coolant leaks and ensures the closed cooling circuit maintains proper pressure and flow.
Compatible Applications
- MerCruiser 3.0L (181 CID) 4-cylinder sterndrive engines
- MerCruiser 3.0L TKS — verify by engine serial number and parts diagram
- Typically paired with Alpha One sterndrives in runabouts and small cruisers
Fitment can vary within the 3.0L MerCruiser family depending on production range and pump housing design. Always confirm part number 879150138 against your engine serial number and the Mercury parts diagram before ordering.
Part Details
- Component type: Circulating water pump mounting gasket
- Sealing location: Between the circulating pump housing and the engine block / front cover
- System: Closed cooling (fresh water / circulating circuit)
- Supersedes: 27-810848 (earlier design)
- OEM status: Genuine Mercury / Quicksilver — not aftermarket
Service Interval
Replace this gasket any time the circulating water pump is removed for service or inspection. It is a single-use sealing component and should never be reused once disturbed. Inspect the pump housing mating surface for corrosion or pitting before installing the new gasket.
Installation Notes
- Clean both mating surfaces thoroughly before installation — remove all traces of the old gasket material.
- Inspect the pump housing and engine block mating surfaces for corrosion, warping, or damage.
- Install the gasket dry or with a thin film of coolant-compatible sealant only if specified in the Mercury service manual.
- Torque pump mounting fasteners to the specification in the MerCruiser service manual for your engine.
- After reassembly, run the engine to operating temperature and check for leaks before returning to service.
Parts Desk Insights
Best use case: This is the correct OEM gasket for MerCruiser 3.0L circulating pump service. It is the right choice any time the pump is being removed — whether for a full pump rebuild, impeller replacement, or leak investigation. Ordering this gasket alongside a pump repair kit ensures the job can be completed in one visit.
Common mistakes: The most frequent error is reusing the original gasket after pump removal — even if it looks intact, a disturbed gasket will not seal reliably and will cause a coolant leak. A second common mistake is confusing the circulating (fresh water) pump gasket with the raw water pump gasket; these are different components on closed-cooling MerCruiser engines. Confirm which pump is being serviced before ordering.
Related Parts
- MerCruiser Water Pump Kit — Complete Service Kit
- MerCruiser Water Pump Kit 96148T8 — OEM Cooling System Service Kit
- Mercury Water Pump Gasket 858524 – MerCruiser Alpha One & Outboard
- Mercury Sea Water Pump Gasket 27-881603001
- Mercury MerCruiser Water Pump Gasket Pack of 2 – 27-34897
- Sierra Marine Circulating Water Pump 18-3575 – MerCruiser GM 4 & 6 Cylinder
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
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We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
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