8d • General discussion
Engine Oil Grades (Petrol vs Diesel) – Easy Guide
1. What “oil grade” means
Engine oil grade tells you how thick or thin the oil is and how it behaves in different temperatures.
Example:5W-30
- 5W = winter (cold start flow)
- 30 = thickness when engine is hot
So the oil has to:
- Flow easily on cold start
- Stay strong and protective when hot
2. Petrol engine oil (spark ignition engines)
Petrol engines:
- Run cleaner
- Produce less soot
- Usually run at higher RPM
Typical oil characteristics:
- Lower soot handling required
- Less detergent needed
- Often lighter oil grades
Common grades:
- 0W-20
- 5W-30
- 5W-40
Key idea:
Petrol oils focus on fuel economy and smooth flow
3. Diesel engine oil (compression ignition engines)
Diesel engines:
- Produce more soot and carbon
- Higher compression = more stress
- Often run longer and heavier loads
Oil must handle:
- More soot contamination 🖤
- Higher pressure
- More heat stress
Common grades:
- 5W-30 (diesel spec)
- 5W-40
- 10W-40 (older engines)
Key idea:
Diesel oils are stronger and more detergent-heavy
0
0 comments
Engine Oil Grades (Petrol vs Diesel) – Easy Guide
powered by
skool.com/the-service-bay-4203
Real mechanic advice, diagnostics, servicing tips & diesel knowledge from a qualified tech with 15+ years workshop experience incl leadership roles!
Suggested communities
Powered by