Cylinder Head Gasket – Fits Yanmar 3HM Series (Replaces 121575-01334)
Cylinder Head Gasket – Fits Yanmar 3HM Series (Replaces 121575-01334) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Cylinder Head Gasket – Fits Yanmar 3HM Series (Replaces 121575-01334)
Product Details
This aftermarket Cylinder Head Gasket is a direct replacement for Yanmar 3HM series marine diesel engines. It is designed to fit 3-cylinder, 35 HP, 4-stroke models including the 3HM, 3HMF, 3HM35, and 3HM35F manufactured between 1981–1988.
It directly replaces Yanmar OEM part numbers 121575-01334, 121575-01333, 121575-01332, and 121575-01331.
- Engineered for direct OEM-equivalent installation.
- Designed for use in marine diesel engine environments.
- Constructed from high-quality, non-asbestos composite materials.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number | Notes |
|---|---|---|
| Yanmar | 121575-01334 | Current Replacement |
| Yanmar | 121575-01333 | Superseded by 121575-01334 |
| Yanmar | 121575-01332 | Superseded by 121575-01333 |
| Yanmar | 121575-01331 | Superseded by 121575-01332 |
Engine & Model Compatibility
Confirm your engine model and year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yanmar | 3HM | 35 | 4-Stroke | 1981–1988 | 121575-01334 | Original superseded: 121575-01331/121575-01332/121575-01333 |
| Yanmar | 3HMF | 35 | 4-Stroke | 1981–1988 | 121575-01334 | Original superseded: 121575-01331/121575-01332/121575-01333 |
| Yanmar | 3HM35 | 35 | 4-Stroke | 1981–1988 | 121575-01334 | Original superseded: 121575-01331/121575-01332/121575-01333 |
| Yanmar | 3HM35F | 35 | 4-Stroke | 1981–1988 | 121575-01334 | Original superseded: 121575-01331/121575-01332/121575-01333 |
Technical Specs
- Product Type
- Cylinder Head Gasket
- Installation
- Direct OEM replacement
- Fuel Type
- Diesel
- Material
- Composite with metal reinforcement
- Dimensions
- 33.0" L x 18.0" W x 0.5" H
- Other Attributes
- Non-asbestos material, meets OEM specifications
What’s in the Box
- 1 x Cylinder Head Gasket (Replaces 121575-01334)
Installation Notes
- Disconnect the battery and drain the engine coolant completely.
- Remove the exhaust manifold, intake manifold, valve cover, and rocker arm assembly.
- Loosen and remove the cylinder head bolts in the reverse order of the manufacturer's tightening sequence.
- Carefully lift the cylinder head off the engine block and remove the old head gasket.
- Thoroughly clean both the cylinder head and engine block surfaces, ensuring they are free of old gasket material, oil, and debris.
- Position the new head gasket correctly on the engine block; do not use any sealant unless specified by the engine manual.
- Carefully place the cylinder head back onto the block.
- Install and torque the head bolts in the correct sequence and stages as per the Yanmar service manual.
- Reassemble all other components in the reverse order of removal.
- Refill the cooling system, reconnect the battery, and start the engine to check for leaks.
Troubleshooting & FAQ
How do I confirm this gasket fits my specific engine?
This gasket is for Yanmar 3HM series engines (3HM, 3HMF, 3HM35, 3HM35F) from 1981–1988. The most reliable way to confirm fitment is to match your existing part number to one of the cross-reference numbers listed: 121575-01334, 121575-01333, 121575-01332, or 121575-01331.
What are the signs of a failed cylinder head gasket?
Common symptoms include engine overheating, white smoke from the exhaust (coolant burning), milky or frothy engine oil (coolant mixing with oil), loss of compression, and poor engine performance. If you notice any of these signs, inspect the head gasket immediately.
Is this gasket made from the same material as the OEM part?
This is an aftermarket gasket made from a high-quality, non-asbestos composite with metal reinforcement, designed to meet or exceed original equipment specifications for sealing performance and durability in a marine environment.
Should I use sealant when installing this gasket?
Generally, modern head gaskets like this one are designed to be installed dry. Applying sealant can interfere with the seal and cause premature failure. Always follow the specific instructions in your engine's service manual.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
