Volvo Penta Thermostat Housing 3583098 | KAD42 KAD43 KAD44 KAD300 OEM

Volvo Penta Thermostat Housing – 3583098

Part Information

• Part Number: 3583098
• Brand: Volvo Penta
• Official Product Type: Thermostat Housing
• OEM Status: Genuine Volvo Penta
• Supersedes: 838704
• System: Engine Cooling – Thermostat / Coolant Routing Assembly
• Related Thermostat Kit: 3831424
• Related Seals: O-ring 968927, Sealing Ring 3583913
• Weight: Approx. 0.8 kg (1.76 lb)

What This Part Does

The 3583098 is the OEM thermostat housing casting used in the engine cooling system of selected Volvo Penta marine diesel engines. It houses the thermostat components and routes engine coolant through the correct cooling passages so that operating temperature is regulated properly. The housing is the structural core of the thermostat assembly — the thermostat kit, O-rings, sealing ring, adapter, and cap are separate service components that fit within or around it.

On KAD42A applications, 3583098 is the confirmed replacement for earlier thermostat housing 838704.

Compatible Applications

• Volvo Penta KAD32P
• Volvo Penta KAD42A / KAD42P-A
• Volvo Penta KAMD42A / KAMD42P-A
• Volvo Penta KAD43P / KAD43P-A / KAD43P-B
• Volvo Penta KAMD43P / KAMD43P-A / KAMD43P-B
• Volvo Penta KAD44P / KAD44P-B / KAD44P-C
• Volvo Penta KAMD44P-A / KAMD44P-B / KAMD44P-C
• Volvo Penta KAD300-A
• Volvo Penta KAMD300-A
• Selected Volvo Penta AD31 / TAMD31 / TMD31 applications
• Selected Volvo Penta AD41 / TAMD41 / TMD41 applications

Confirm the exact engine model, serial number, thermostat count, hose routing, and cooling-system diagram before ordering. Volvo Penta used several thermostat housings and related caps across KAD, KAMD, TAMD, and AD-series engines. The safest fitment check is a factory parts diagram showing 3583098 or the earlier 838704 at the thermostat-housing position.

Serial Number Fitment Notice

Use your engine serial number to locate the correct Volvo Penta cooling-system or thermostat assembly diagram and confirm that 3583098 is specified at the thermostat housing position before ordering. Housing configurations can vary by serial-number range even within the same engine family.

When to Replace

• Housing casting is cracked, pitted, or badly corroded
• Sealing surfaces are warped or damaged beyond cleaning
• Coolant leaks repeatedly around the housing or hose connections
• Hose connection necks are corroded or damaged
• Thermostat seats are distorted or worn
• Internal scale buildup restricts coolant flow through the housing
• Cooling-system service reveals deterioration around the thermostat assembly

Marine diesel thermostat housings are commonly compromised by internal corrosion and scaling that is not visible from the outside. If the sealing surfaces are pitted or the internal passages are restricted, replacing the thermostat kit alone will not resolve the problem.

Service Interval

Volvo Penta does not publish a fixed replacement interval for the thermostat housing itself. Inspect at each thermostat service for corrosion, scaling, and sealing-surface condition. Replace if any deterioration is found that could affect cooling-system sealing or flow. On engines that have seen many years of service, proactive housing replacement during a thermostat service is common practice.

Installation Notes

When replacing the thermostat housing, inspect and replace all associated components while the assembly is open:

• Thermostat kit 3831424
• O-rings 968927
• Sealing ring 3583913
• Adapter 838739
• Plugs, flange screws, and fasteners
• Connecting hoses and clamps

Clean all mating surfaces carefully and remove scale without damaging the sealing faces. Install new O-rings and seals — never reuse disturbed sealing components. Follow the Volvo Penta service procedure for thermostat orientation, fastener torque, coolant refill, air bleeding, and leak verification. Run the engine to operating temperature and confirm stable temperature regulation and no coolant leaks before returning to service.

Technical FAQ

Q: Does 3583098 replace 838704?
A: Yes, on KAD42A and related applications. Volvo Penta 3583098 is the current housing and supersedes the earlier 838704.

Q: Is 860449 the same as 3583098?
A: No. 860449 is a related thermostat-housing cap or assembly reference — it is not a direct replacement for the housing casting itself. Confirm which part number is specified at your exact position in the parts diagram before ordering.

Q: Does the thermostat kit come with the housing?
A: No. The 3583098 is the housing casting only. Thermostat kit 3831424, O-rings 968927, sealing ring 3583913, and adapter 838739 are separate service parts. Order all required components before beginning disassembly.

Q: Can I reuse the old O-rings if they look serviceable?
A: No. Any O-rings or sealing rings that have been disturbed during disassembly should be replaced. Reusing compressed seals is a common cause of repeat leaks after a thermostat service.

Alternate Part Numbers

• Volvo Penta 3583098
• 838704 (superseded)

Parts Desk Insights

The most common mistake with this part is ordering only the thermostat kit when the housing itself is the source of the leak. On KAD and KAMD diesel engines that have been in service for many years, the thermostat housing sealing surfaces and internal passages often corrode from the inside out, and a new thermostat in a pitted or scaled housing will leak again quickly. The other issue to flag is the distinction between the housing (3583098) and related components like the cap (860449) and adapter (838739) — confirm each part number from the cooling-system diagram before ordering. Have all the O-rings, seals, and thermostat kit on hand before starting the job so the engine isn’t sitting with the cooling system open waiting for parts.