Synthetic vs Conventional Oil: What's the Difference?
Conventional oil is refined from crude oil and full synthetic oil is chemically engineered, but neither is automatically the "right" oil for your car. The correct oil is the one that meets the viscosity, performance specification, and manufacturer approval your specific vehicle requires.
The Simple Difference
Conventional Oil
Refined from crude oil. It is the base motor oil used in many engines that were designed and approved for it.
Synthetic Blend
A mix of conventional and synthetic base oils, used where a vehicle's requirements call for it.
Full Synthetic
Chemically engineered base oils with more uniform molecules. Many engines specifically require a full synthetic that meets a stated specification.
What Matters More Than the Label
"Full synthetic" on the bottle does not automatically mean the oil is correct for your vehicle. Four things decide that:
- Viscosity grade — the weight the manufacturer requires, such as 0W-20 or 5W-30
- Performance specification — the industry or manufacturer standard the oil must meet
- Manufacturer approval — some vehicles require an oil carrying a specific factory approval
- Whether synthetic is required — some engines are built to run only on a full synthetic that meets those requirements
Oil Types and Our Current Pricing
Conventional
$69.99
Up to 5 quarts and a standard oil filter.
Synthetic Blend
$89.99
Up to 5 quarts and a standard oil filter.
Full Synthetic
$89.99
Up to 5 quarts and a standard oil filter.
- Additional oil over 5 quarts is $7.99 per quart.
- European vehicles, diesel engines, and specialty filters may cost more.
Can You Switch From Conventional to Synthetic?
It may be possible, but the replacement oil still has to meet the viscosity, performance specification, and any manufacturer approval your vehicle requires. Changing oil type does not override those requirements. If you are considering a switch, we can confirm what your engine is approved to run before the service.
Does Synthetic Mean You Can Wait Longer Between Oil Changes?
Not automatically. Your service interval is determined by the manufacturer's maintenance schedule and, on many vehicles, by the oil-life monitoring system — not by whether the oil is synthetic.
How often should you change your oil?European and Specialty Applications
Some vehicles — commonly European models and diesel engines — require oils carrying specific manufacturer approvals along with specialty filters, and some hold more than 5 quarts. In those cases standard advertised pricing may not apply. Call with your year, make, and model and we will confirm what your vehicle takes.
What Four Mile Fork Garage Does
We identify the oil your vehicle actually requires — viscosity, specification, and any manufacturer approval — and perform the oil change with that oil and the correct filter. Walk-ins are welcome, and timing depends on the vehicle and current shop availability.
See our oil change service and pricingSynthetic vs Conventional Oil FAQ
Is synthetic oil always better than conventional oil?
No. The correct oil is the one that meets the viscosity, performance specification, and any manufacturer approval your vehicle requires. Synthetic oil is the right choice when your vehicle calls for it, and conventional oil is correct when the manufacturer specifies it.
Can I switch from conventional to synthetic oil?
It may be possible, but the replacement oil still has to meet the viscosity, specification, and any approval your vehicle requires. Changing oil type does not override the manufacturer's requirements.
Does full synthetic oil let me wait longer between oil changes?
Not automatically. The maintenance interval is set by your manufacturer's maintenance schedule or your vehicle's oil-life monitoring system, not by the label on the bottle.
What does 0W-20 or 5W-30 mean?
Those are viscosity grades. The number before the W describes how the oil flows when cold, and the second number describes its viscosity at operating temperature. Your manufacturer specifies which grade your engine requires.
Can I use conventional oil to save money?
Only if your vehicle is approved for it. If the manufacturer requires a synthetic oil meeting a specific standard, substituting a cheaper oil that does not meet that requirement is not appropriate for the engine.
Why can European oil changes cost more?
Some European vehicles require oils carrying specific manufacturer approvals along with specialty filters, and some take more than 5 quarts. European vehicles, diesel engines, and specialty filters may cost more than the standard advertised pricing.
How do I know which oil my car requires?
Your owner's manual lists the required viscosity, specification, and any manufacturer approval. If you are unsure, we can identify the required oil for your year, make, and model.