Engine Protection
Bolec DCS974T – Temperature Switch
Kubota engine overheat protection with a surface-mount probe, fail-safe logic, and 12/24 V flexibility.
IP65 Housing12/24 V Systems
Alarm / Shutdown
Why DCS974T for Kubota?
- Perfect retrofit: Surface-mount probe slips under an existing bolt on the head or inlet manifold.
- Fail-safe logic: Open probe or poor mounting triggers alarm/shutdown instead of silence.
- Flexible outputs: Volt-free relay drives lamp/buzzer or a fuel-solenoid shutdown via relay.
- 12/24 V ready: Suits Kubota tractors, gensets, pumps, and marine conversions.
Key specs
| Supply | 12 VDC (8–16.5 V) or 24 VDC (16–33 V) |
|---|---|
| Probe range | +20 °C to +120 °C (surface) |
| Relay output | Volt-free NO, max 3 A resistive (12 V) / 1.5 A (24 V) |
| Status LEDs | Green = Power; Red = Over-temperature / Fault |
| Housing | ABS, IP65 |
| Dimensions | 64 (H) × 58 (W) × 35 (D) mm |
| Leads | 200 mm colour-coded |
Reverse-polarity protected. See manual for full wiring and commissioning steps.
Kubota-specific installation
Recommended probe locations
- Cylinder head bolt near thermostat housing/water outlet (fast response)
- Inlet manifold bolt if head bolts are hard to access
- Thermostat housing bolt for early coolant-related rise
⚠️
Avoid exhaust-side hot spots that don’t reflect coolant temperature—can cause nuisance trips.
Wiring overview
IGN + → Red (via 3–5 A fuse) • GND → Black
Probe → Two probe leads (non-polar) • Relay → COM + N/O to lamp/buzzer or stop-solenoid
Set the trip temperature
1 Turn trim pot fully clockwise (max)
2 Warm engine to normal temp (~80–90 °C coolant)
3 Turn anticlockwise until red LED lights (trip point)
4 Back clockwise until LED turns off, then +2–3 mm
Typical surface trip points: D722/D902/V1505 → 95–100 °C; V2203+ → 98–102 °C.
FAQs
Is the DCS974T suitable for Kubota engines without built-in temperature monitoring?
Yes. The surface-mounted probe fits under an existing bolt on the head or manifold, so you can add overheat protection without modifying coolant plumbing. Use the relay for alarm or to drive a shutdown relay.
Will it work on 24 V Kubota machines?
Yes. It supports both 12 V (8–16.5 V) and 24 V (16–33 V) systems. Ensure the driven load is within the relay rating.
Alarm-only vs automatic shutdown — which should I choose?
For operators who can respond quickly, alarm-only (lamp/buzzer) is simple and low-risk. For unattended gensets or pumps, auto-shutdown via fuel-solenoid is safer. Many installers wire both: alarm first, then shutdown after a short delay using a separate timer.
How do I avoid false trips on hot days or after shutdown?
Mount on a location that reflects coolant temperature (head near thermostat). Set the trip point slightly above normal running temp. Keep probe away from exhaust manifolds and ensure good metal-to-metal contact under the bolt.
What happens if the probe wire breaks?
The unit operates in a fail-safe manner — it will trip the relay (and red LED) on an open-circuit probe so protection isn’t lost.
What relay loads can I drive?
Use the volt-free NO contact: up to ~3 A resistive at 12 V (≈1.5 A at 24 V). For higher-current devices (beacons, sirens), use this output to trigger an external automotive relay.
Where exactly should I mount it on common Kubota models?
As a rule: D722/D902/V1505 → cylinder head bolt near the thermostat housing; V2203+ → head bolt or thermostat housing bolt. Use thread anti-seize and re-torque to spec after fitting the probe eyelet.
How often should I test it?
At each service interval: check bolt tightness, inspect wiring for heat/chafe, and verify the alarm by temporarily lowering the trip point until the red LED/relay activates, then restore the setting.
Can I combine DCS974T with other Bolec protections?
Yes. Common combos are DCS974T (over-temp) + WL601/WL701 (low coolant) + TM301 timer (shutdown delay). Wire through a small relay/diode logic so alerts don’t fight each other.
Ready to protect your Kubota?
Add DCS974T to every engine you install or service—it’s affordable insurance against overheating.