STP® Smoke Treatment is designed for petrol engines to provide a thick oil cushion to help fill gaps created between the cylinder walls, piston rings valve guide seats on worn engines and reduce oil blow-by and smoking. This engine smoke treatment reduces exhaust smoke and engine noise, lowers oil consumption and protects against engine wear. How it helps: Protects against engine wear. Reduces excessive smoking and noise. Creates thick and protective oil cushion. Compatible with petrol engines.