18-3653 Thermostat Kit for OMC Volvo Penta Mercruiser | JLM Marine

18-3653 Thermostat Kit for OMC Volvo Penta Mercruiser | JLM Marine

This 160°F thermostat kit is engineered for OMC Sterndrive/Cobra applications and is compatible with Volvo Penta and Mercruiser engines spanning from 1969 to 1988. It provides reliable temperature regulation across a wide range of horsepower ratings—from 90 HP to 454 HP—and displacement sizes including 3.8L, 4.3L, 5.0L, 5.7L, and 7.5L models.

Direct Replacement for: Mercruiser 802259, 802326 | OMC 379754, 383307, 3852216, 3856961, 778056 | Volvo Penta 3852127, 3852216, 3856961 | GLM 13430 | Sierra 18-3653, 18-3554, 18-3677.

• Complete kit with thermostat, O-ring, gaskets, and housing gasket for fast installation
• Rated at 160°F for optimal cooling performance in marine inboard/sterndrive applications
• Fits dozens of OMC engine models from 1969–1988, covering popular displacement classes

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

This complete thermostat kit includes everything you need for a straightforward installation:

• 1 × Thermostat (160°F)
• 1 × O-ring
• 1 × Gasket
• 1 × Gasket (additional)
• 1 × Housing Gasket

Installation Guide

1. Allow the engine to cool completely before beginning work. Relieve cooling system pressure by slowly opening the pressure cap.
2. Locate the thermostat housing on your engine block and disconnect any hoses or electrical sensors as needed.
3. Remove the housing bolts and carefully lift the housing away. Take note of the old thermostat's orientation.
4. Clean all gasket surfaces thoroughly using a gasket scraper and suitable solvent; ensure no old gasket material remains.
5. Install the new O-ring onto the thermostat body, then position the thermostat in the housing with the correct orientation (spring side typically down).
6. Place the new gasket(s) onto the mating surfaces and position the housing back onto the engine block.
7. Reinstall and torque the housing bolts to manufacturer specifications in a crisscross pattern.
8. Reconnect hoses and sensors, then refill the cooling system with the recommended coolant mixture.
9. Start the engine and allow it to reach normal operating temperature while checking for leaks around the thermostat housing.
10. Top off coolant as necessary and re-check the system after a short test run.

Troubleshooting & FAQ

Q: How do I confirm this thermostat kit fits my OMC, Volvo Penta, or Mercruiser engine?
A: Cross-reference your engine's model, horsepower, and year with the compatibility table above. Also verify your existing thermostat's OEM part number against the cross-reference list to ensure a match.

Q: What are the signs that my thermostat needs replacement?
A: Common symptoms include engine overheating, failure to reach normal operating temperature, erratic temperature gauge readings, or coolant leaks around the thermostat housing. If you notice any of these issues, inspect and replace the thermostat as needed.

Q: How often should I replace my marine thermostat?
A: Most marine thermostats should be inspected annually and replaced every 2–3 years or per your engine manufacturer's maintenance schedule. Replace sooner if you experience overheating or cooling system issues.

Q: Does this kit include all necessary gaskets and seals?
A: Yes, this kit includes the thermostat, O-ring, multiple gaskets, and a housing gasket—everything required for a complete installation without additional parts.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.