DGP vs. Standard Bar Oils (Viscosity & Flow Test)
DGP is not a universal chainsaw-oil grade, so the label alone cannot confirm that it will work in your saw. Compare the product’s technical data sheet with the saw maker’s oil recommendation, then check delivery at the temperature you expect to cut in. Viscosity matters, but the pump, oil passages, bar, and operating conditions matter too.
A quality bar and chain deserve the right lubricant, not a guess based on a bottle label. I compare oils by their published viscosity and by whether the saw delivers enough oil with that product installed. There is no single flow-rate target that fits every chainsaw, so the saw’s service information is the deciding reference.
Equipment setup & safety prep
This section helps you confirm that the oil, saw, bar, and chain belong together before comparing products. Start with the saw maker’s lubricant recommendation and service manual. Since “DGP” is not a universal oil specification, you need the exact product name and its technical data sheet before making a product-specific choice.
Check what “DGP” means on the product label
“DGP” does not identify one standard viscosity or guarantee suitability for chainsaw bars and chains. Treat it as a product or brand description until the maker’s documentation says what the oil is designed for. If you cannot find a technical data sheet, contact the maker or use the saw maker’s recommended bar-and-chain oil.
Look for these details on the product data sheet:
- Intended use: It should state that the oil is suitable for chainsaw bars and chains.
- Kinematic viscosity: Compare the value in mm²/s, also called cSt, at 40 °C. ASTM D445 is a common method for measuring this property.
- Temperature information: Check for viscosity data at, or guidance for, the temperature where you will operate.
- Product limits: Follow any stated storage, temperature, or handling instructions.
A viscosity number without its test temperature is not a complete comparison. Two oils can behave differently in the cold even if their published viscosity at 40 °C appears close.
Verify the saw and cutting equipment
Bar oil cannot correct a mismatched bar or chain. Confirm that the bar, chain pitch, chain gauge, drive-link count, and drive sprocket match the saw maker’s specifications. For example, 3/8-inch low-profile pitch with .050-inch gauge is one possible setup, not a universal fit.
There is no reliable universal bar-length-to-engine-displacement rule. Use the approved bar lengths listed for your exact saw model. Also check the oil tank, outlet, and bar oil holes for dirt or blockage before changing products.
If your saw has an adjustable oil pump, use only the model’s instructions and limits. Do not alter the setting to force an unfamiliar oil through the system.
Prepare safely before a flow check
Wear chainsaw-rated leg protection, a helmet with eye and face protection, hearing protection, gloves, and suitable boots. Check the chain brake, throttle lockout, chain catcher, handles, and chain condition. Set a clear work area, control bystanders, and follow workplace rules where they apply.
For a gasoline saw, use the fuel mixture specified for that exact model. A 50:1 ratio applies only when the maker specifies it. Battery saws have no fuel-mix requirement. Keep bar oil separate from fuel; never pour it into the fuel tank.
Field cutting/landscaping operation
A useful comparison holds the saw, bar, chain, temperature, and test method constant while changing only the oil. The goal is not to find which oil looks thicker. It is to confirm that the chosen oil meets the saw maker’s delivery requirement and keeps the bar and chain lubricated.
Compare viscosity and flow, not label claims
Viscosity describes a fluid’s resistance to flow. Higher viscosity often means a thicker-flowing oil under the same conditions, but it does not tell you by itself how much oil a particular chainsaw will deliver. Pump design, temperature, oil passages, and pump condition all affect delivery.
| Comparison item | DGP product | Standard recommended oil | What to check |
|---|---|---|---|
| Product identity | Exact name and maker | Exact name and maker | Confirm both are bar-and-chain oils |
| Viscosity | ___ mm²/s (cSt) at 40 °C | ___ mm²/s (cSt) at 40 °C | Use the TDS, not an unqualified “thick” or “thin” description |
| Working temperature | ___ °C | ___ °C | Use maker guidance or published temperature data |
| Saw delivery | ___ per approved test | ___ per approved test | Compare with the saw’s specification |
| Result | Pass / fail / unknown | Pass / fail / unknown | Watch for poor lubrication or abnormal oiling |
If a data sheet gives no viscosity or temperature guidance, do not assume that the oil is equivalent to the standard product. “Biodegradable,” “premium,” or “all-season” does not replace a stated specification.
Run a controlled, safe delivery check
Use the manufacturer’s test method if one is published. Keep the same saw, clean oil reservoir, bar, chain, pump setting, operating condition, and test duration for both oils. Record the ambient temperature, product and batch, saw model, bar and chain details, and any delivery result.
Before testing, clean the oil outlet and bar groove, check chain tension, and fill the oil tank. Never run the chain dry to see what happens. If the manual allows a measured delivery test, use its safe procedure. A trained technician may use a controlled gravimetric method, which measures mass change over a fixed interval, but only with an approved setup that keeps people clear of the moving chain.
Do not invent a flow target: there is no universal chainsaw bar-oil rate. Compare the result with the specification for your exact saw. A visible oil trace can support an inspection, but a fling test is not a quantitative flow measurement.
Apply the result to real cutting conditions
These are practical examples, not measured product tests:
- Cold morning, unknown DGP viscosity: If the product has no cold-temperature guidance, the result is uncertain. Use the saw maker’s recommended oil rather than assuming that a warm-weather flow check proves cold-weather performance.
- DGP flows below the saw specification: Stop the comparison. Check for a blocked outlet, dirty groove, pump issue, or unsuitable oil. Do not dilute the oil or turn the pump beyond its stated limits.
- Both oils meet the specification: Either may be suitable if both makers support the intended use and the saw continues to lubricate normally under actual conditions.
Use DGP only when its maker identifies it for chainsaw bars and chains and the saw delivers the required oil at the working temperature. Stop cutting if lubrication is absent or inadequate.
Maintenance & sharpening/tuning
Oil performance depends on a clean, sound cutting system. A blocked oilway can make a suitable oil appear inadequate, while an unsuitable oil can restrict delivery even when the saw is clean. Inspect the bar and chain before blaming the product or changing pump settings.
Find the cause of poor lubrication
Stop immediately if you see smoke, unusual heat, blueing, or no oil delivery. Switch off and isolate the saw; for a battery model, remove the battery according to the manual. Let hot parts cool before inspection.
Then check the oil level, outlet, bar holes, and groove. Look for packed debris, a damaged bar, worn rails, a worn sprocket, or a chain that is too tight. If those checks do not explain the problem, follow the service manual or have a qualified technician inspect the pump.
Oil that is too viscous for the pump and temperature, a blocked passage, or a failing pump can reduce lubrication. The chain may overheat, stretch, or seize. Those conditions can lead to derailment or loss of control, so do not keep cutting to “see if it clears.”
Keep oil tests separate from chain service
Do not mix test oils in the reservoir or leave an unknown blend in the saw. Drain and clean the system only as directed by the saw and oil makers. Record the oil, temperature, and test result so you can repeat the comparison under similar conditions.
Clean the bar groove and oil holes as part of routine care. Inspect the chain, drive links, bar rails, and sprocket. Sharpen with the file size and angles specified by the chain maker, and set depth gauges to that chain’s stated dimension. There is no single file angle or depth-gauge setting for every chain.
Storage & seasonal care
Storage care helps preserve oil delivery and makes the next comparison more useful. Follow the equipment maker’s storage instructions for the saw, fuel system, battery, and cutting equipment. Keep bar oil separate from fuel, and use seasonal oil only when its data and the saw maker’s guidance support the expected temperature.
Store the saw and oil for the conditions ahead
For gasoline saws, manage fuel as the engine maker directs. Bar oil is a separate lubricant and must never go into the fuel tank. For battery saws, follow the battery maker’s storage temperature and charge guidance.
Clean the saw, bar, chain, and oil passages before storage. Protect the cutting equipment, and store the saw securely away from children. Keep the oil in its original, closed container and observe its label instructions.
Cold-weather performance can differ from warm-weather results. If you compare oils in different seasons, record the temperature; otherwise, the change in flow may reflect the conditions rather than the product alone.
Make the final choice
Choose DGP only when its data sheet confirms chainsaw bar-and-chain use and the saw meets its specified delivery requirement with that oil at your working temperature. If product data are missing, delivery is uncertain, or lubrication looks abnormal, use the saw maker’s recommended oil and investigate the equipment.
The practical decision is straightforward: verify the product, check the saw, test by the approved method, and stop if lubrication fails.
FAQ
Is DGP a standard chainsaw bar-oil grade?
No. “DGP” is not a universal bar-oil specification. Check the exact product maker and technical data sheet to confirm intended use and viscosity.
What viscosity should I compare for bar oil?
Compare kinematic viscosity in mm²/s, or cSt, at 40 °C, using the product data sheet. Also check any temperature guidance for your operating conditions.
Does thicker bar oil always protect the chain better?
No. A thicker oil may not flow properly through a pump in cold conditions. Protection depends on suitable oil, adequate delivery, and a clean, working lubrication system.
What is the correct bar-oil flow rate for my chainsaw?
There is no universal rate. Use the oil-delivery specification or test procedure for your exact saw model.
Can I use DGP if the bottle does not list viscosity?
Only if the maker confirms it is suitable for chainsaw bars and chains and provides enough guidance for your conditions. Otherwise, the product’s performance is unknown; use the saw maker’s recommended oil.
Can I thin bar oil with solvent or another oil?
No. Do not dilute or blend oils to change flow. Use a suitable product and follow the saw maker’s pump limits.
Does a visible oil fling prove that flow is correct?
No. A visual trace may show that some oil is present, but it does not measure delivery. Compare results with the saw maker’s specification using an approved test.
Can I use the same bar oil in a battery saw?
Often, battery saws use bar-and-chain oil, but check the saw maker’s instructions. Battery power removes the fuel-mix requirement, not the need for proper bar lubrication.
What should I do if the bar gets unusually hot?
Stop and isolate the saw. Let it cool, then inspect the oil level, outlet, bar holes, groove, chain, and pump according to the manual. Do not resume until lubrication is restored.
Is 50:1 the correct fuel mix for every chainsaw?
No. Use only the ratio specified for your exact gasoline saw. Battery saws do not use premixed fuel.
(This article was written by one of our staff writers, David Hensley. Visit our Meet the Team page.)
