This is the genuine Kubota thermostat for the 03-M Series engines. Kubota’s parts lists show it on the D1803-M and V2003-M diesels and the WG1903 and WG2503 gas and LPG engines, and it replaces 1A021-73012, the thermostat on the D1503-M and V2203-M. Kubota tractors that use it include the L2800, L3400, L3800, L4400, L4600, MX4700, MX5000 and MX5100, along with the L45 and the KX121-3, KX161-3 and U45 excavators.

Replace it when the engine runs cold, is slow to warm up, or runs hot with a full, clean radiator. Kubota thermostats look alike from one engine family to the next, so match the number on your old part or have the engine model and serial number ready.

Specifications

Fits / Applications

• Kubota WG2503 gasoline, LPG and dual-fuel engines (from engine serial 7JQ0001; earlier engines used 1A021-73012, which this part replaces)
• Kubota WG1903 gasoline and dual-fuel engines
• Kubota D1803-M and V2003-M diesel engines (from engine serial 7JQ0001; earlier engines used 1A021-73012)
• Kubota D1503-M and V2203-M diesel engines that used 1A021-73012
• Kubota L Series tractors: L2800, L3130, L3240, L3400, L3430, L3540, L3700SU, L3800, L3830, L3940, L4240, L4330, L4400, L4600, L4630, L4740, L5030, L5040, L5240 and L5740
• Kubota MX4700, MX5000 and MX5100 tractors and the M4800SU and M5640SU
• Kubota L45
• Kubota KX121-3 and KX161-3 excavators and the U45

Part Numbers & Cross Reference

Kubota (older number) 1A021-73012

Cross-reference numbers can change with engine serial, build year and emissions tier, so treat this list as a starting point. Send us your engine serial number and we will confirm the exact match against your build before anything ships. That check is free and takes a few minutes.

Frequently Asked Questions

Does the 1A021-73013 replace the 1A021-73012 thermostat?

Yes. Kubota’s parts lists show 1A021-73012 up to engine serial 7JPZ999 and 1A021-73013 after that, and 1A021-73013 is the current number for both.

Will it fit my MX5100 or MX4700?

Yes. Two Kubota dealer catalogs list 1A021-73013 for the MX4700 and MX5100, and Kubota’s MX5100 parts book shows the older 1A021-73012 that it replaces.

Is this the same thermostat as the one in a D1105 or an older V2203?

Not always. The 05 Series engines take 19434-73015, and so do some 03 Series builds: Kubota’s parts lists show it on the V2203-E2B and V1903-E2B industrial engines, and a Kubota dealer catalog lists it for the L4310 and KX121-2. Match the number on your old thermostat.

How do I confirm it for another L Series tractor or excavator?

Call 530-668-0818 with the machine model and the engine model and serial number. Kubota used this thermostat on many L Series and MX machines, and we will check yours against the parts list.

Related Parts

• Kubota D1503, D1703, V2203 & V2403 Low Mount Water Pump (KX121-3, KX161-3, U35) | Genuine Kubota 1A051-73036
• Kubota Thermostat Gasket for D902, D1105, D1803-M, V2403-CR & WG Engines | Genuine Kubota 16221-73270

Why Buy From Valley Fuel Injection

We are an authorized Kubota dealer and a diesel fuel-injection shop in Woodland, CA, working on diesel engines since 1993. When you call, you talk to people who know Kubota engines, and we check the part number against your engine serial or machine model before anything ships, so the right part arrives the first time. See our Kubota engine sales, parts and service.