Mercury MerCruiser Oil Temperature Sender Assembly 849363 | 500 CARB 502 CID 8.2L Gen VI NLA

Mercury MerCruiser OEM Oil Temperature Sender — Part 849363

• Part Number: 849363 (also referenced as 849363-1)
• Brand: Mercury Marine / MerCruiser (Genuine OEM)
• Official Product Type: Engine Senders & Sensors — Oil Temperature
• System: Engine Electrical / Instrumentation — Oil Temperature Monitoring
• Diagram Position: Oil temperature sender location in the engine electrical group — separate from the water temperature and oil pressure senders on the same engines
• GTIN: 745061418127
• Qty Required: 1 per engine
• OEM Availability: Currently listed as no longer available (NLA) from Mercury. Order promptly — remaining stock is limited.
• Weight: approx. 0.15 kg (0.33 lb)
• Estimated packed dimensions: approx. 3.15 in. × 1.97 in. × 1.97 in. (8.0 cm × 5.0 cm × 5.0 cm)

What It Does

This is the genuine OEM oil temperature sender used on selected Mercury MerCruiser high-performance big-block engines fitted with oil temperature instrumentation. It connects to the oil temperature gauge in the helm instrumentation package and provides the resistance-based signal that drives the gauge reading. This is a distinct component from the water temperature sender and oil pressure sender on the same engines — the three senders serve separate functions and are not interchangeable.

Compatible Applications

Verify fitment by engine model, serial number, and instrumentation package before ordering.

• MerCruiser 500 CARB (502 CID / 8.2L) — serial range 0F745195 through 0F877722
• MerCruiser 502 CID / 8.2L Gen VI — serial range 0K000001 through 0L001772
• MerCruiser 500 EFI
• MerCruiser 500 Bulldog (502 CID)
• MerCruiser 540 Stroker 4V
• MerCruiser 575 SCi
• MerCruiser 800 SC (572 CID)
• MerCruiser 900 SC

Not sure it fits? Send us your MerCruiser engine serial number and instrumentation details before ordering.

Important: Gauge System Compatibility

Do not select this sender by appearance or thread size alone. Mercury electrical diagrams identify two separate oil temperature senders for some of these engines:

• 849363 — Standard Mercury instrumentation (this part)
• 8503671 — Separate oil temperature sender for Gaffrig gauge applications — not interchangeable with 849363 without confirming the gauge system

The correct sender depends on the original instrumentation package fitted to your engine. Confirm which gauge system is installed before ordering.

Related Parts

• Mercury MerCruiser Quicksilver Water Temperature Sender 806490T — water temperature sender used on the same engines
• Mercury MerCruiser Quicksilver Oil Pressure Sender 8M0068784 — oil pressure sender used on the same engines
• 49734 — optional dual water temperature sender (search by part number)
• 37293T — optional dual oil pressure sender (search by part number)
• 22-64013 — engine block reducer fitting used with sender installations on 500 CARB / 8.2L assemblies (search by part number)

When to Replace

Replace the oil temperature sender if:

• The oil temperature gauge reads incorrectly or stays fixed at one extreme
• Temperature readings are intermittent or erratic
• The terminal or sender body is corroded or physically damaged
• The sender body leaks at the installation point
• Wiring, grounds, and the gauge have all tested correctly but the sender signal remains faulty

Before replacing, verify the wiring, terminal connection, ground path, and gauge circuit are all functioning correctly. A faulty gauge reading is not always caused by the sender.

Service Interval

There is no fixed replacement interval — replace on condition. Inspect the sender and terminal connection during any instrumentation or electrical service, and replace when physical damage, corrosion, or a confirmed faulty signal is found.

Installation Notes

• Disconnect battery power before servicing the sender circuit
• Identify and label the sender wire before removal
• Confirm the replacement matches the original gauge system (standard Mercury vs. Gaffrig)
• Inspect the electrical terminal and harness connector for corrosion before reconnecting
• Do not overtighten the sender into the engine block or adapter fitting
• Follow the applicable Mercury MerCruiser service procedure for sender installation and electrical testing

Technical FAQ

Q: What is the difference between 849363 and 8503671?
Both are oil temperature senders for similar MerCruiser high-performance engines, but Mercury diagrams identify them for different gauge systems — 849363 for standard Mercury instrumentation, and 8503671 for Gaffrig gauge applications. They are not automatically interchangeable.

Q: Is 849363 still available from Mercury?
Mercury dealer data currently shows 849363 as no longer available (NLA). If you need this sender, order promptly as remaining new stock is limited.

Q: Can I use a water temperature sender in place of the oil temperature sender?
No. These are separate senders matched to their respective gauges. Substituting one for the other will produce incorrect readings.

Q: What should I check before replacing the sender?
First verify the wiring, terminal connections, ground path, and gauge are all functioning correctly. A faulty reading is not always caused by the sender itself.

Parts Desk Insights

The most important thing to know about 849363 is that it is the oil temperature sender, not the water temperature sender that most MerCruiser owners encounter first. It was used specifically on selected high-performance big-block engines that included oil temperature instrumentation, and Mercury listed a completely separate sender (8503671) for engines fitted with Gaffrig gauges — these are not interchangeable. Because 849363 is currently NLA, it is worth ordering as a spare now if your engine uses it. The most common issue we see is customers ordering the wrong sender because the thread size looks similar to the water temp sender or the oil pressure sender on the same engine. Always confirm the sender matches the gauge system, not just the engine model.