The most common Hisun 500 problems are overheating and head gasket failure, smoking and stalling, no-crank starting problems, heat under the dump bed, water in the oil, and belt or shifting complaints. Cooling system care is the single most important thing on this machine, because overheating leads to the most expensive failures.
The Hisun 500 (sold as the HS500 and, through some home-improvement stores, under names such as the Axis 500) is a budget utility side-by-side. The 2021 HS 500 uses a 471cc liquid-cooled, fuel-injected single-cylinder engine with a CVT (high, low and reverse), selectable 2WD/4WD with differential locks, and a 1,200 lb towing rating.
Hisun 500 Problems at a Glance
| Problem | Common symptom | Most likely cause | First fix to try | Part you may need |
|---|---|---|---|---|
| Overheating / head gasket | Temp warning, radiator cold, white smoke | Air in cooling system, water pump, blown gasket | Purge air, check water pump and flow | Head gasket, water pump, coolant |
| Smoking and stalling | White/gray smoke, dies on throttle | Coolant in cylinder, leaking gasket | Stop driving; pressure-test cooling system | Head gasket kit |
| No crank | Lights work, starter silent | Battery, ground, wiring, safety switch | Test battery and grounds before parts | Battery, starter relay |
| Hot dump bed | Bed floor very hot after driving | Exhaust heat, loose exhaust | Tighten exhaust, add heat shield | Heat shield |
| Water in oil | Milky oil | Condensation from short trips (or gasket leak) | Run longer trips, change oil, rule out gasket | Engine oil, filter |
| Belt / shifting | Slipping, hard shifting | Worn belt, linkage, idle too high | Inspect belt, adjust shift linkage | Drive belt |
1. Overheating and Head Gasket Failure
Overheating is the most serious Hisun 500 complaint. One owner of a Hisun 500 reported overheating soon after purchase: the radiator stayed cold while the engine got hot and smoked from the exhaust. The head gasket had failed. A cold radiator on a hot engine means coolant isn’t circulating, usually from trapped air, a failed water pump or a stuck thermostat.
How to fix it
- Stop driving as soon as the temperature light comes on.
- When cold, check the coolant level in the radiator and overflow tank.
- Bleed (purge) air from the cooling system following the service manual. Trapped air is common after coolant work.
- Warm the engine and feel the upper radiator hose. If it stays cold while the engine heats up, check the thermostat and water pump.
- Confirm the cooling fan switches on.
- If you see white smoke or coolant loss, have a cooling system pressure test or combustion leak test done.
Fix overheating right away. Running hot is what blows the head gasket, and a damaged gasket can leak coolant into the cylinder and cause hydrolock.
Parts you may need: coolant, thermostat, water pump, head gasket kit.
2. Smoking and Stalling After Overheating
In the same case, the owner replaced the head gasket and water pump, but the engine still smoked white/gray and stalled whenever he touched the throttle. Other owners suggested the new gasket was leaking or the head was warped. Before cranking an engine that has been leaking coolant, remove the spark plug and turn the engine over by hand to make sure the cylinder isn’t full of coolant.
- Remove the spark plug and check for coolant on it or in the cylinder.
- Have the cylinder head checked for flatness and cracks before fitting a new gasket.
- Use a new gasket and torque the head to spec in the correct sequence.
- If smoking continues after a correct repair, the engine may need a professional rebuild.
3. No-Crank Starting Problems
One owner’s 2021 Hisun 500 ran on after the key was turned off, then would not crank even though the lights, turn signals and horn worked. He replaced the starter solenoid, starter and starter switch without fixing it. Lights working doesn’t prove the battery can turn the starter, so test before buying parts.
- Measure battery voltage with a digital multimeter; it should be about 12.6 V charged and stay above roughly 10 V while cranking.
- Clean and tighten the battery terminals, the main ground to the frame and the starter cable.
- Check the brake, neutral and seat safety switches, which can block the starter.
- Test for voltage at the starter relay when the key is turned to start.
- Only then replace the relay or starter.
Parts you may need: battery, starter relay, battery cables.
4. Hot Dump Bed
Owners of the Hisun Axis 500 report the dump bed getting very hot after a few miles, apparently from exhaust heat. One owner found the exhaust was loose and tightening it helped; another added a heat shield under the bed. Don’t carry anything heat-sensitive in the bed until you’ve fixed it.
5. Water in the Oil
Milky oil can come from condensation when the machine only makes short trips and never gets fully warm. It can also mean a leaking head gasket. Change the oil, take a longer drive to get the engine fully hot, and check again. If the oil turns milky again and coolant is dropping, suspect the head gasket.
6. Belt and Shifting Problems
- Use low range for loads and hills to reduce belt heat.
- Inspect the belt for glazing and cracks, and replace it if worn.
- If it’s hard to shift into gear, make sure the engine is at idle, then check the shift linkage adjustment.
Parts you may need: drive belt, shift linkage parts.
Useful tools: keep 50/50 premixed coolant on hand for top-ups and use a battery maintainer during storage.
Maintenance That Prevents Most Hisun 500 Problems
| How often | What to do |
|---|---|
| Before every ride | Check coolant level and look for leaks |
| After dusty or muddy work | Clean the radiator and air filter |
| Monthly | Check battery voltage, oil condition and tire pressure |
| Every season | Inspect belt, shift linkage, wiring and exhaust mounts |
| Per owner’s manual | Engine oil and filter, spark plug, valve clearance, coolant |
Frequently Asked Questions
What engine is in the Hisun 500?
The 2021 Hisun HS 500 uses a 471cc liquid-cooled, fuel-injected single-cylinder engine with a CVT.
Why is my Hisun 500 radiator cold when the engine is hot?
Coolant isn’t circulating. Check for trapped air in the cooling system, a stuck thermostat or a failed water pump.
Why won’t my Hisun 500 crank when the lights work?
The battery may be too weak to turn the starter, or there may be a bad ground, safety switch or relay. Test voltage while cranking before replacing parts.
Is the Hisun 500 a good UTV?
It’s an affordable machine with useful features such as 4WD and diff locks, but owners report cooling problems and limited dealer support, so it suits buyers who can do their own maintenance.
Conclusion
Most serious Hisun 500 problems start with overheating. Keep the coolant full and air-free, make sure the water pump and fan work, and stop at the first sign of overheating, and you avoid the head gasket failures owners report most.
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