Husqvarna 390 XP Bar Oil Leak (Causes & Fixes)
A small amount of oil under a Husqvarna 390 XP after storage can be normal: oil may drain from the bar groove or clutch-cover area. A continuing pool, a damaged hose or seal, or no oil reaching the chain needs attention. Clean the saw, trace where fresh oil appears, and verify chain lubrication before cutting.
Imagine you finish a job, park the saw, and find a wet spot beneath it the next morning. Is the oil tank cracked, or is this just leftover oil draining from the bar? The answer matters: replacing parts without finding the source wastes money, while running a dry chain can damage the bar and chain.
I diagnose this by separating normal residue from an active leak, then checking the oil path from tank to chain. Work with the engine off and cool. Use the manual for your saw’s production version when a specification or removal step varies.
Equipment Setup, Leak Diagnosis & Safety Preparation
This first check separates oil left on the saw after use from a fault in the tank, seal, hose, pump, or drive. A leak’s location and whether fresh oil appears while the saw sits are more useful than the size of one old puddle. Clean first, then inspect in stages.
Before working, shut off the engine, let it cool, and clean off sawdust and oil. Wear gloves and eye protection while handling the chain. Before later operation, use the required chainsaw PPE: helmet with face and eye protection, hearing protection, chainsaw chaps, gloves, and boots. Check the chain brake, throttle lockout, chain catcher, and fasteners before starting.
Tell normal residue from an active leak
Oil clings to the bar groove, chain, and clutch-cover area after use. Some can drain out during storage, leaving a small spot that does not keep growing. That alone does not prove the oil tank or pump has failed.
To check:
- Wipe the powerhead, underside, bar, and clutch-cover area dry.
- Check the oil level, then add the correct bar-and-chain oil if needed. Do not overfill.
- Place the saw on clean cardboard, away from heat or ignition sources. Leave it off.
- Note where fresh oil appears and whether the spot grows. Recheck after the saw has stood for a while.
A wet patch directly under the bar tip or cover may be residual oil. Oil reappearing at a tank seam, cap, hose connection, or powerhead outlet points to a part that needs closer inspection. Do not run the saw just to make it leak faster.
Inspect the oil path
Remove the bar and chain with the saw off, following the manual. Keep clear of the sharp cutters. Clean the bar groove, the bar’s oil inlet holes, and the oil outlet on the crankcase. Packed sawdust or oil residue can block flow and make a sound oil system seem faulty.
Look for a cracked tank, damaged cap seal, loose or split oil hose, and visible damage around the pump area. Check the oil outlet for blockage. If oil pools from the powerhead after cleaning, or the source is hidden behind parts you cannot safely remove, stop and use the correct service procedure or a qualified repair shop.
The 390 XP is an approximately 88 cm³ two-stroke saw. Its fuel system and bar-oil system are separate. The fuel should be fresh gasoline mixed 50:1 with quality air-cooled two-stroke oil that meets Husqvarna’s specification. Never put bar oil in the fuel tank or use an unverified fuel mix to troubleshoot an oil leak.
Field Cutting Operation & Lubrication Checks
The goal of this check is to confirm that oil reaches the chain before cutting. A working oil system leaves a steady trace of oil from the moving chain; a dry, smoking, or unusually hot chain is a stop signal. Follow the manual’s test method, since output changes with the pump setting and operating conditions.
After addressing any visible leak, fit the bar and chain specified for your saw’s exact version. Bar length, chain pitch, gauge, and drive-link count must all match. Many 390 XP setups use 3/8-inch standard-pitch chain, but the gauge can vary, including .058 or .063 inch. Do not assume .050-inch or low-profile chain fits. Common bar lengths may fall around 18 to 28 inches, but confirm approved lengths in the manual.
Set chain tension cold as the manual directs. Check that the chain is sharp and its cutters are even. Set depth gauges to the chain maker’s specification; there is no single clearance that applies to every chain.
Start and warm the saw as directed. Keep a safe stance, secure footing, and a clear escape route. Use the manual’s oil-delivery test over clean cardboard or another suitable surface. Confirm a consistent oil trace from the chain; do not assume a universal flow rate or adjust the pump by guesswork. The pump is adjustable on applicable versions, but the correct setting depends on the saw and setup.
Stop immediately if the chain is dry, smoking, unusually hot, loose, or dull. A blocked oil passage, failed pump drive, or mismatched bar and chain can starve the chain of oil. Continued cutting can overheat or stretch the chain, damage the bar, or cause the chain to derail or seize. Never keep cutting to use up the oil in the tank.
Maintenance, Chain Sharpening & Oil-System Repair
Maintenance addresses the likely source only after inspection identifies it. A damaged seal, hose, pump, or pump drive calls for the correct replacement part; a blocked outlet calls for cleaning. Do not apply improvised adhesive to oil passages. It can block flow and hide the real fault.
| Finding after cleaning | Likely area to inspect | Next step |
|---|---|---|
| Small spot near the bar or clutch cover; no fresh oil at the tank or powerhead | Oil left in the groove or cover | Clean, store on cardboard, and check whether oil continues to appear |
| Fresh oil at the cap or tank seam | Cap seal, cap fit, or tank damage | Inspect for visible wear or cracks; replace damaged parts |
| Oil appears around a hose connection or beneath the powerhead | Oil hose, connection, or pump area | Inspect for cracks or looseness; replace damaged parts |
| Oil outlet is dirty, and chain oiling is weak or absent | Bar inlet holes, groove, or crankcase outlet | Clean the passages and retest by the manual |
| Oil does not reach the chain after passages are clean | Pump, pump drive, or worm gear | Inspect and replace worn or damaged components using the service procedure |
A worm gear is the drive part that transfers motion to the oil pump. If the pump does not turn or its drive is worn, cleaning the bar will not restore oil delivery. Check the pump drive and gear when the outlet is clear but the chain still receives no oil. Parts access and assembly details can vary, so use the service manual for your version.
Two diagnostic examples
These are illustrative scenarios, not reports of a specific repair. They show how the order of checks can prevent replacing a sound part.
- Small spot after storage: The saw is dry after cleaning, but oil appears near the clutch cover later. The bar groove and cover contain oil residue. Clean those areas and repeat the stationary check. If no fresh oil appears at the tank or powerhead and chain delivery is correct, a pump replacement is not justified by the old spot alone.
- Oil leak continues, chain stays dry: The saw is cleaned, the bar outlet is clear, and oil still pools from the powerhead while the chain receives none. Inspect the hose, pump, and pump drive. Replace only the damaged component, then verify delivery before cutting.
For both examples, the finding that matters is what happens after cleaning. A single puddle cannot identify the failed part. If the leak source remains unclear, avoid buying a tank, pump, or hose based only on where the oil lands.
Repair and verify
Replace a damaged tank seal, hose, or oil pump with parts that match the saw’s version. If inspection shows a worn or damaged pump drive or worm gear, repair that as well. Do not seal the outlet or hose with glue, tape, or other improvised materials.
After assembly, refit the correct bar and chain, set the tension cold, and check that the chain moves as intended with the engine off and brake released. Then follow the manual’s starting and oil-delivery test. If the chain remains dry or oil continues to pool from the powerhead, shut down and repair the source before cutting.
The engine’s published idle and maximum-power speeds are approximately 2,500 rpm and 9,600 rpm, but confirm specifications for the exact production version. Do not try to fix poor oiling by tuning the engine by ear or exceeding its specified maximum speed.
Shutdown, Cleaning & Seasonal Storage
Correct shutdown and storage help keep old bar oil from being mistaken for a new fault. They also make it easier to spot fresh oil next time. After work, stop the engine, engage the chain brake, allow the saw to cool, and clean the bar groove and cover before storing it.
Check the oil level and chain tension, and look for new damage or wet areas. Store the saw away from heat and ignition sources. If a small spot appears later, clean the saw and repeat the cardboard check before replacing parts. If oil continues to pool from the powerhead, or chain lubrication fails, do not return the saw to cutting until the oil system is repaired.
Frequently Asked Questions
Is it normal for a Husqvarna 390 XP to leak bar oil while stored?
A small spot can come from oil draining out of the bar groove or clutch-cover area. Clean the saw and check whether fresh oil keeps appearing.
Why does oil leak from the clutch-cover area?
Oil can remain in the bar groove and cover after use and drain during storage. Clean both areas first; inspect the tank, hoses, and pump area if fresh oil returns.
Can I run the saw to find the leak?
Do not run it just to create a leak. First inspect it cold and clean. Run only after assembly, using the manual’s oil-delivery check.
What if the chain is dry but the tank has oil?
Stop. Check that the bar groove, inlet holes, and crankcase outlet are clear. If oil still does not reach the chain, inspect the pump and drive.
Can I use motor oil instead of bar-and-chain oil?
Use purpose-made bar-and-chain oil. Choose its viscosity for the ambient conditions and follow the saw manual.
Does a 390 XP always use .050-inch chain?
No. Match pitch, gauge, and drive-link count to the bar and saw version. Common 3/8-inch setups can use .058- or .063-inch gauge.
Should I replace the oil pump if the saw leaves a puddle?
Not based on a puddle alone. First clean the saw and trace fresh oil. Replace the pump only when inspection or testing points to a pump fault.
Can I keep cutting if the chain is smoking or hot?
No. Stop the engine. A dry or overheated chain may point to blocked oil flow or a pump-drive problem.
Is bar oil the same as two-stroke fuel oil?
No. Bar oil lubricates the chain. Two-stroke oil is mixed with gasoline at the specified ratio, commonly 50:1 for this saw, using oil that meets Husqvarna’s requirements.
When should I take the saw for service?
Get qualified service if oil continues pooling from the powerhead, the leak source is hidden, or the chain receives no oil after the passages are clean and the pump system has been checked.
(This article was written by one of our staff writers, Robert Callahan. Visit our Meet the Team page.)
