Mercury MerCruiser Quicksilver Thermostat Cover Gasket 62386001

Thermostat Cover Gasket — OEM Reference 62386001 / 27-62386001

Part Number: 62386001 | Service format: 27-62386001
Brand: Mercury Marine / Quicksilver
Official Product Type: Thermostat Cover Gasket
Supersedes: 62386 / 27-62386 / 27-62386B (earlier references)
Replaced By: 8M0204714 / 27-8M0204714 (current OEM replacement)
System: Engine Cooling — Thermostat Cover / Cylinder Head
Diagram Position: Between thermostat cover and cylinder-head mating surface, sealing the thermostat assembly to the cooling passage
GTIN: 745061164895

What This Gasket Does

This genuine Mercury Marine / Quicksilver gasket seals the thermostat cover to the cylinder head on selected Mercury and Mariner outboard engines, maintaining a leak-free seal at the cooling-water passage around the thermostat assembly. It is specifically a thermostat cover gasket — not a generic cooling-system gasket — and the profile is matched to the thermostat cover and cylinder-head opening of the applicable engine. On many Mercury 2.5L V6 engines, two thermostat assemblies are present (one per cylinder bank), so the quantity required should be confirmed from the engine serial number and parts diagram.

Compatible Applications

Fitment depends on exact engine model, thermostat housing layout, and serial number. Confirm against your Mercury parts diagram before ordering.

• Mercury / Mariner V-135, V-150, V-175, V-200 (2.5L V6)
• Mercury / Mariner 140 Jet 2.5L
• Mercury / Mariner 200 DFI Jet Drive
• Mercury V-200 EFI 2.5L
• Mercury XR-6 and Magnum III (2.5L V6 powerheads)
• Mercury / Mariner 150 / 175 / 200 DFI 2.5L (OptiMax-family)
• Mercury 200XS and Pro XS (confirm by serial number)
• Selected Mercury / Mariner 55, 60, 65 Jet, 75, 80 Jet, 90 DFI, 115, 115 DFI, 125 HP applications (serial-number dependent)

Serial number note (2.5L V6): One documented application shows:

• 27-62386 — serial numbers 0T979999 and below
• 27-62386001 — serial numbers 0T980000 and up

Always confirm the correct gasket version using your engine serial number and the thermostat / cylinder-head diagram.

When to Replace This Gasket

Replace whenever the thermostat cover is removed, or if the existing gasket is torn, compressed, hardened, stuck to the mating surface, or showing evidence of cooling-water leakage around the thermostat cover. Installing a fresh gasket during thermostat service ensures a proper seal at the cylinder-head cooling passage.

Service Interval

Replace at every thermostat service or any time the thermostat cover is disturbed. Thermostat cover gaskets are single-use components — reusing a compressed or disturbed gasket risks cooling-water leakage.

Dimensions

Weight: approx. 0.01 kg | Sold individually — order quantity per the diagram (many 2.5L V6 applications require 2 per engine, one per bank).

Installation Notes

• Remove all old gasket material from both the thermostat cover and cylinder-head mating surfaces without damaging the aluminum.
• Inspect the thermostat, cover, fasteners, and cooling passages while the assembly is open.
• Install the gasket in the correct orientation shown in the Mercury parts diagram.
• Tighten thermostat-cover fasteners to the torque specification in the Mercury service manual for your engine.
• If your engine has two thermostat assemblies, replace both gaskets at the same time.

Kit Contents

Single gasket. Sold individually. Confirm quantity required from your engine serial number and parts diagram — many 2.5L V6 applications require two gaskets per engine.

Alternate and Superseded Part Numbers

• Current OEM replacement: 8M0204714 / 27-8M0204714
• This part: 62386001 / 27-62386001
• Earlier references: 62386 / 27-62386 / 62386B / 27-62386B
• Aftermarket cross-reference: Sierra 18-0182, GLM 30610, Mallory 9-60002
• Related interchange: OMC / Johnson / Evinrude 0310058 / 310058

Related Parts

• Thermostat — replace during cover gasket service if due; verify by engine model and serial number
• Thermostat cover / housing — inspect for corrosion or warping while disassembled
• Thermostat cover fasteners — inspect for corrosion and replace if damaged
• Thermostat O-ring or seal — verify by engine model and serial number

Parts Desk Insights

The detail that catches customers off guard with this gasket is the two-per-engine requirement on many 2.5L V6 applications. Each cylinder bank has its own thermostat assembly, and ordering only one gasket for a V6 leaves the second bank without a fresh seal. Always check the quantity field in the parts diagram before ordering. The supersession from 62386001 to 8M0204714 is also worth noting — if your parts system shows 62386001 as unavailable, the current replacement 8M0204714 is the correct substitute and shares the same GTIN.

Technical FAQ

Q: Can I reuse the old thermostat cover gasket?
No. Once compressed and disturbed, gaskets do not re-seal reliably. Always install a fresh gasket when the thermostat cover is removed.

Q: Is 8M0204714 the same gasket as 62386001?
Yes — 8M0204714 is the current OEM replacement for 62386001. It may differ visually while performing the same sealing function and shares the same GTIN.

Q: My 2.5L V6 has two thermostats — how many gaskets do I need?
Two — one per cylinder bank. Confirm by your engine serial number and the cylinder-head / thermostat diagram to be certain.

Q: What is the difference between 62386 and 62386001?
62386 is the earlier reference used on serial numbers 0T979999 and below on documented 2.5L V6 applications. 62386001 supersedes it for serial numbers 0T980000 and up. Confirm your serial number before ordering.