Customer Service: info@jlm-marine.com
Free shipping. No Minimum Purchase
Crankshaft Position Sensor 3858979 – Fits Volvo Penta OMC 4.3–5.7L
- $53.77
- $53.77
- Unit price
- per
Couldn't load pickup availability
Free Shipping
Free standard shipping on all orders
Worry-Free Returns
Learn More.
How to Match This Part
This aftermarket crankshaft position sensor replaces Volvo Penta / OMC 3858979 (also catalogued for MerCruiser / Quicksilver as 864297T01, including 864297 and 864297001). It mounts at the timing cover and reports crankshaft position and speed to the ECM so ignition timing and fuel delivery stay synchronized on gasoline sterndrive and inboard engines.
Match this part in this order:
1. OEM number on the removed sensor or in your parts catalog — 3858979 (Volvo Penta / OMC) or 864297T01 / 864297 / 864297001 (MerCruiser)
2. Engine brand and displacement — gas OMC / Volvo Penta 4.3L, 5.0L, or 5.7L, or the MerCruiser models listed below
3. Physical form — compare the mounting style, connector, and overall shape with the product images and with the sensor you remove
This sensor is intended for GM-based marine engines that use a composite (plastic) timing cover with a crank-sensor port. If your original sensor carries a different OEM number, or your timing cover has no sensor port, do not use this part even if the displacement matches.
Part Number Cross-Reference
Use these verified numbers to confirm you have the correct crankshaft position sensor. Brand names and OEM numbers are for identification only.
| Type | Brand | Part Number | Notes |
|---|---|---|---|
| OEM | Volvo Penta / OMC | 3858979 | Primary reference (crankshaft position sensor) |
| OEM | Mercury MerCruiser / Quicksilver | 864297T01 | Also catalogued as 864297 and 864297001 |
| OEM | Indmar | 556293 | Interchange OEM number for the same sensor family |
| Aftermarket | Sierra Marine | 18-7706 | Volvo Penta / OMC replacement listing |
| Aftermarket | Sierra Marine | 18-7556 | MerCruiser replacement listing for the same sensor family |
| Aftermarket | Mallory Marine | 9-29820 | Direct cross-reference |
| Aftermarket | CDI Electronics | E13-0003 | Direct cross-reference |
This is an aftermarket part manufactured by JLM Marine. It is not sold as a genuine Volvo Penta, OMC, Mercury, MerCruiser, Quicksilver, or Indmar component.
Compatible Engine Models
Confirm brand, displacement, and the original sensor number before ordering. On Volvo Penta and OMC gasoline engines the identification plate is typically on the block or flywheel housing; on MerCruiser sterndrive and inboard engines it is on the block or near the flame-arrestor cover. Always match the OEM number and physical form of the sensor you remove. MerCruiser owners can also cross-check diagrams at Mercury Parts Diagrams.
| Brand | Engine Model | Notes |
|---|---|---|
| Volvo Penta | 4.3L, 5.0L, 5.7L gasoline sterndrive | Replaces 3858979; composite timing cover |
| OMC Cobra | 4.3L, 5.0L, 5.7L gasoline sterndrive | Replaces 3858979; composite timing cover |
| MerCruiser | 4.3L Carb / MPI | Replaces 864297T01 |
| MerCruiser | 5.0L MPI, 5.7L MPI, 6.2L MPI | Replaces 864297T01; composite timing cover |
| MerCruiser | 350 Magnum | Replaces 864297T01 |
| MerCruiser | 525 EFI | Replaces 864297T01 |
Engines outside this list are not covered by this listing. If your original sensor number differs, confirm compatibility before ordering.
Technical Specifications
| Specification | Value |
|---|---|
| Part type | Crankshaft position sensor |
| Primary OEM replaced | Volvo Penta / OMC 3858979 |
| Also replaces | MerCruiser / Quicksilver 864297T01 (864297 / 864297001) |
| Engine application | Marine gasoline sterndrive and inboard (GM-based V6 / V8) |
| Mounting location | Timing cover crank-sensor port |
| Timing cover requirement | Composite (plastic) timing cover with sensor port — not for metal covers without a port |
Installation Guide
- 1 Disconnect the battery negative cable and allow the engine to cool before working near the timing cover.
- 2 Unplug the harness from the original sensor, then remove the mounting fastener and withdraw the sensor from the timing-cover bore. Note bracket orientation and lead routing before removal.
- 3 Compare the new sensor with the old one side by side. Mounting style, connector, and overall shape must match before installation.
- 4 Clean the mounting bore and sealing face. Seat the new sensor fully without forcing it, then refit the fastener to the torque in your engine service manual.
- 5 Reconnect the harness until the lock clicks. Route the lead clear of belts, pulleys, and hot exhaust components, then reconnect the battery.
- 6 Clear any stored crank or timing fault codes with a marine diagnostic tool, start the engine, and confirm a stable idle and correct RPM reading before returning the boat to service.
Note: Professional installation is recommended for EFI crankshaft position sensors.
Troubleshooting & FAQ
Important Notes
- Match the OEM number and the physical form of your original sensor before ordering. A different connector or mount means a different part.
- Confirm a composite timing cover with a crank-sensor port. This sensor is not for metal covers without that port.
- This is an aftermarket part. Brand names and part numbers are for reference only.
- Professional installation is recommended for EFI crankshaft position sensors.
Why Choose JLM MARINE?
- Precision Fit: Cross-referenced to Volvo Penta / OMC 3858979 and MerCruiser 864297T01 for the applications listed above.
- Quality Control: Each batch is inspected for dimensional consistency and workmanship.
- Direct from Manufacturer: Aftermarket marine sensors engineered for reliable crankshaft-position feedback on gasoline sterndrive EFI systems.
We can ship to virtually any address in the world with free shipping available for most regions.
For our typical US and Canadian customers , our shipping timeframes are as follows:
- Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
- US warehouse shipment: orders will be delivered within 5 days after placing the order.
- China warehouse shipment: orders will be delivered about 12 days after placing the order.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.
As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.
We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.
Parts Finder
Use our Parts Finder to quickly locate the correct parts for your engine. Search by Make, HP, Stroke, Model, Year, and SN.
Select only the fields available — you don’t need to fill all options (e.g., leave Year blank if not applicable).
Our database is currently being updated and expanded. More models, including Yamaha, Mercury, and Suzuki, are being verified and uploaded.
Our database is currently being updated and expanded. More models, including Yamaha, Mercury, and Suzuki, are being verified and uploaded.
- Choosing a selection results in a full page refresh.