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.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- beginner
- Estimated cost
- $25-$600
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Common Symptoms
- Low coolant lamp / buzzer
Probable Causes (Ranked by Likelihood)
- Leak at heat exchanger end cap O-ring Likely
- Leaking coolant hose Likely
- Cracked expansion tank on older YM series Possible
Step-by-Step Diagnostic Procedure
Pressure-test cooling system to locate leak.
Inspect heat exchanger end caps for seep stains.
Top off with Yanmar-approved ethylene glycol.
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?
Typical repair cost: $25-$600. Off-road diesel shop labor runs $125-$175/hr in 2026. Dealer diagnostic software (Yanmar SmartAssist / YDT) is usually required.