YANMAR-LOW-COOLANT serious Yanmar ›

Yanmar Marine Low Coolant Alarm

The YANMAR-LOW-COOLANT (Yanmar) diesel fault code means: Yanmar Marine Low Coolant Alarm. This is a serious severity code.

My Garage →
Keep driving?
Limited driving only
DIY difficulty
beginner
Estimated cost
$25-$600

What Are the Symptoms of YANMAR-LOW-COOLANT?

  • Low coolant lamp / buzzer

What Causes YANMAR-LOW-COOLANT? (Most Likely First)

  • Leak at heat exchanger end cap O-ring Likely
  • Leaking coolant hose Likely
  • Cracked expansion tank on older YM series Possible

Can I Still Drive with YANMAR-LOW-COOLANT?

Limited driving only. YANMAR-LOW-COOLANT is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.

Frequently Asked Questions

What is Yanmar code MARINE-LOW-COOLANT?

Yanmar MARINE-LOW-COOLANT: Yanmar Marine Low Coolant Alarm. This code is reported on Yanmar equipment running the described engine family.

Can I keep working with Yanmar code MARINE-LOW-COOLANT?

Limited operation only -- finish the current task then shut down for repair.

How much does Yanmar MARINE-LOW-COOLANT cost to fix?

Estimated repair cost: $25-$600. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.

Mechanics Guide Step-by-step diagnosis

How Do You Diagnose YANMAR-LOW-COOLANT?

  1. Pressure-test cooling system to locate leak.

  2. Inspect heat exchanger end caps for seep stains.

  3. Top off with Yanmar-approved ethylene glycol.

Which Vehicles Commonly Get YANMAR-LOW-COOLANT?

  • Hunter / Beneteau / Catalina sailboats with Yanmar 3JH / 4JH
  • Trawlers and sport fishing boats with Yanmar 6LY / 6LF series
  • Sailboat auxiliaries with Yanmar 2YM / 3YM / 3JH5 diesels
  • Commercial fishing vessels with Yanmar 6LY3-UTP
  • Yachts with Yanmar 6LY400 / 6LY440 / 8LV common-rail marine diesels
  • Workboats with Yanmar 4LV / 4JH series marine propulsion
  • Ski boats and express cruisers with Yanmar marine diesels
  • Tenders and RIBs with Yanmar 3YM20 / 3YM30 sailboat aux
  • Island-hopper ferries with Yanmar 6AYM / 6HYM commercial series
  • Tug boats and small workboats with Yanmar 6HAL-HTP / 6HYM

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