Need to replace a 333-0677-02 or 333-0677-01 Cummins Onan block heater? Our 4990W heater retrofit kits provide adequate amounts of heat to your engine, without redesigning the OEM configuration of the block heater plumbing. These kits include new inlet and outlet block heater hoses with new hose clamps. These retrofit kits can replace a 333-0677-02 or 333-0677-01 Onan Water Heater; they're in stock, ready to ship today.

Despite the reduced amount of heat (4990W vs 6420W) provided with this heater, the difference in wattage was offered on all varieties of Cummins Onan generator sets as an option. 4990W heaters provide ~78% of the wattage of the larger 6420W and won't require modifications to the building wiring or overcurrent protection devices. The 4990W heaters will perform well, and actually reduce the cycle rates of your block heater thermostats to provide a more constant flow of heat. Depending on specific generator set application and model number, may require new mounting holes to be drilled in bracket; contact us for additional details and clarification for your application.

Block heater thermostats (P/N 309-0649) and control relay(s) are also available at our store. Please see our online store for additional offerings, or to combine shipments with these other recommended block heater replacement parts.

307-3089 Block Heater Relays -> https://www.ebay.com/itm/295516077180

309-0649 Block Heater Thermostat -> https://www.ebay.com/itm/295516648740

307-2859 Block Heater Relay Contactor Assembly -> https://www.ebay.com/itm/295516567077

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