A well-maintained air compressor should deliver clean, dry air. But if your Sullair compressor is blowing oil into your air lines or exhausting it into the environment, something is wrong. Oil carryover is a common problem in rotary screw compressors, and while Sullair builds durable machines, even the best compressors can develop oil separation issues over time. This guide explains the top reasons for oil blow-by, how to fix it, and which premium compressors are reliable alternatives if yours is nearing the end of its service life.
Quick Picks: Best Compressors to Avoid Oil Problems
- Best Overall: Atlas Copco GA Series Rotary Screw — Excellent oil separation, advanced controls.
- Best Budget: Ingersoll Rand 2475N7.5-P T-30 — Durable reciprocating alternative with no oil separator to fail.
- Best Premium: Kaeser CSD Series Rotary Screw — German engineering, ultra-low oil carryover.
Buyer’s Guide: Why Sullair Compressors Blow Oil
1) Failed or Saturated Oil Separator
The oil separator is designed to remove oil from compressed air. If it’s clogged, saturated, or worn, excess oil passes into the air stream.
2) High Oil Levels
Overfilling oil in the sump tank increases oil carryover. Always check levels against manufacturer markings.
3) Incorrect Oil Type
Using non-OEM or low-quality oil can foam and cause poor separation, pushing oil downstream.
4) Blocked Return Line
The oil return line sends separated oil back to the sump. If blocked, oil accumulates and blows into the air system.
5) Excessive Pressure Drop
Dirty filters and clogged separators increase pressure drop, reducing oil separation efficiency.
6) Worn Components
Older compressors with worn seals, bearings, or rotors allow more oil to bypass normal separation systems.
How to Fix Oil Blow-By
- Check and replace oil separator filter (2,000–4,000 hours typical life).
- Drain and refill with OEM-approved Sullair oil.
- Inspect and clear oil return lines.
- Check system pressure and replace clogged air filters.
- Schedule professional service if seals or rotors are worn.
Detailed Product Reviews (Premium Alternatives $2,000+)
1. Atlas Copco GA Series Rotary Screw
Who it’s for: Shops wanting premium oil separation and advanced monitoring.
- Key Benefits: Smart controllers, efficient separators, quiet operation.
- Pros: Low oil carryover, excellent service network.
- Cons: Higher upfront price.
Final Verdict: The gold standard for oil-free reliability. Check price
2. Ingersoll Rand 2475N7.5-P T-30
Who it’s for: Buyers who want a simple reciprocating unit with fewer oil separation parts to fail.
- Key Benefits: Cast iron pump, 80-gallon tank, 24 CFM @ 175 PSI.
- Pros: Durable, fewer oil issues than rotary screws.
- Cons: Louder than screw compressors.
Final Verdict: A strong budget alternative. View deal
3. Kaeser CSD Series Rotary Screw
Who it’s for: Industrial buyers needing ultra-clean air and long service life.
- Key Benefits: Energy-efficient Sigma profile rotors, advanced oil separation system.
- Pros: Extremely reliable, low oil carryover.
- Cons: Premium price.
Final Verdict: Best for facilities demanding consistent air quality. See pricing
4. Quincy QSI Rotary Screw
Who it’s for: American-made alternative with rugged reliability.
- Key Benefits: Cast-iron housing, heavy-duty separators, industrial performance.
- Pros: Long lifespan, strong support.
- Cons: Larger footprint.
Final Verdict: A great U.S.-built competitor. View deal
5. Sullivan Palatek Rotary Screw
Who it’s for: Heavy industries needing maximum uptime.
- Key Benefits: High CFM delivery, durable components, strong oil separation.
- Pros: Built for 24/7 duty.
- Cons: Industrial price tag.
Final Verdict: Ideal for continuous-duty operations. Check availability
6. Saylor-Beall Reciprocating Compressor
Who it’s for: Buyers preferring simple, low-maintenance designs.
- Key Benefits: Cast-iron construction, long life, basic maintenance.
- Pros: Easy to repair, fewer oil separation issues.
- Cons: Louder, lower efficiency vs. rotary screws.
Final Verdict: A rugged old-school option. See offer
Comparison Table
| Model | Type | Oil Carryover Control | Best For | Price Link |
|---|---|---|---|---|
| Atlas Copco GA | Rotary Screw | Advanced separators | Premium industrial use | Check Price |
| Ingersoll Rand 2475N7.5-P | Reciprocating | No oil separator needed | Shops on budget | View Deal |
| Kaeser CSD | Rotary Screw | Ultra-low oil carryover | High-demand facilities | See Pricing |
| Quincy QSI | Rotary Screw | Heavy-duty separation | Industrial shops | View |
| Sullivan Palatek | Rotary Screw | 24/7 separation system | Heavy industry | Check |
| Saylor-Beall | Reciprocating | Simpler oil system | Traditional buyers | View |
FAQ
Why is my Sullair compressor blowing oil?
Most often, the oil separator is saturated or failed, the return line is blocked, or oil is overfilled.
Can I keep running it if oil is blowing out?
No. Oil carryover can damage air tools, foul dryers, and create safety issues.
How often should I change the oil separator?
Typically every 2,000–4,000 hours, depending on operating conditions and maintenance schedules.
What oil should I use in my Sullair compressor?
Always use OEM-approved Sullair compressor oil or synthetic equivalents to prevent foaming and blow-by.
When should I replace instead of repair?
If the compressor is older, requires frequent separator changes, or oil issues persist, upgrading to a modern compressor is often more economical.
Conclusion & Call-to-Action
Sullair compressors blowing oil usually point to separator or oil return issues. While many problems can be fixed with proper maintenance, aging machines may keep leaking oil despite repairs. If reliability matters, upgrading to a modern compressor like the Atlas Copco GA or Kaeser CSD ensures cleaner air and lower operating costs. Budget buyers can step into a proven Ingersoll Rand T-30 or Saylor-Beall for long-term peace of mind.
Protect your tools and air quality—shop the best industrial compressors today and say goodbye to oil carryover problems.