How to Reduce Engine Blowby With Oil Treatment

by Max Stout
Jupiterimages/ Images

As vehicles age, wear can create gaps between moving internal engine parts which lead to blow-by. Blow-by is a condition caused by combustion leakage through piston rings and valve stem guides. Oil treatment products thicken engine oil to fill these gaps and reduce blow-by through improved performance. Adding oil treatment also aids in conditioning worn, dry oil seals to help stop engine oil pan and valve cover leaks. You can add an oil treatment product to your vehicle's engine with minimum automotive engine experience.

Step 1

Allow the engine to cool before performing work.

Step 2

Remove the ignition keys from the vehicle to ensure that the engine will not be started. Place the shift lever in the "Park" position if the vehicle is equipped with an automatic transmission or first gear if it is a standard shift. Set the emergency brake.

Step 3

Open the hood of the vehicle.

Step 4

Locate the engine oil filler cap and remove it. Many engine filler caps have an image of an oil can on them. If its location is not conspicuous, use the owner's manual to locate it.

Step 5

Remove the engine oil filler cap by turning it in a counterclockwise direction. Some oil caps act as plugs and can be readily removed by pulling them straight out with a slight twisting motion. Use a shop towel to help grip the cap if needed.

Step 6

Insert the smaller end of the funnel into the oil filler tube.

Step 7

Add the oil treatment product to your engine by pouring the prescribed amount into the mouth of the funnel as dictated by the product manufacturer's recommendations. Be sure to use a clean funnel, free of foreign particles.

Step 8

Remove the funnel after the oil treatment has run out of it. As you begin to remove it with one hand, place a shop towel over the spout end to prevent any drippings from falling onto the engine.

Step 9

Install the oil filler cap back into place.

Step 10

Close the hood of the car securely.

Start the engine and allow it to warm up to normal operating temperature. This will blend the oil treatment with the engine oil completely.


  • Ideally, it's best to add an oil treatment product after an engine oil change.
  • Replace the engine oil with one grade heavier than your last oil change. Straight oil weights, such as 40-weight, can be used in the warmer seasons. During the winter months, use 20 or 30 weight oil. The heavier weight oil will help to reduce blow-by and provide better lubrication for older engines.

Items you will need

  • Vehicle owner's manual
  • Shop towels
  • Oil treatment product
  • Funnel

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