How to slow the engine valve seals from leaking

Updated April 17, 2017

The engine valve seals have a very specific function in the automobile engine. They restrain oil from travelling down between the valve stem and valve guide, where it could enter the combustion chamber. If the valve seals have shrunken, overheated or turned brittle, oil passes down into the combustion chamber, resulting in excessive oil consumption, which can be seen as blue smoke exiting the exhaust. You may use special products and a few simple maintenance steps to decrease oil consumption as a result of worn or deformed valve seals.

Put your transmission shift selector in park or neutral, depending upon your vehicle type. Apply the emergency brake. Let the engine remain warm, but not hot. If hot, let the engine cool. Raise the vehicle front end with a floor jack and place two jack stands under the front part of the frame near the wheels. Raise the vehicle rear end and place two jack stands under the frame near the wheels. Make certain the vehicle sits level, so the oil pan sump can drain properly.

Place a drain pan under the oil drain plug. Loosen and remove the drain plug with a socket and wrench. Allow the oil to drain into the pan until it stops dripping. Inspect the O-ring gasket on the drain plug. If crushed or deteriorated, replace the O-ring with a new one. Replace the oil drain plug and tighten it with a socked. Place a band-type oil filter wrench over the oil filter body and twist it counterclockwise to loosen the filter. Unscrew the filter and let the oil drain into the pan.

Check for an oil ring gasket stuck to the top of the filter housing flange, and remove it. Dab a finger in the used oil and smear it on the O-ring on the new oil filter. Screw the oil filter up into the mounting flange by hand. Hand-tighten it firmly -- do not use the oil filter wrench for tightening. Raise the hood and locate the oil filler tube or dipstick location, depending upon your vehicle type.

Place a funnel in the dipstick location or filler tube. Refer to your owner's manual for the oil capacity and viscosity of your vehicle. You will need to add a higher viscosity oil to your crankcase. If you currently use 5W-30, you will need to add 10W-30 or 10W-40 for this oil change. Pour in the full amount of oil, minus one quart of your crankcase capacity. Pour in the contents of a seal conditioner, according to the instructions. Remove the funnel and replace the dipstick or filler tube cap.

Start the engine and let it run for 15 minutes. Shut the engine off. Check the oil level with a clean rag. Add any additional oil to bring the level up to the maximum line on the dipstick. Replace the dipstick. Run the engine for 500 miles to let the seal conditioner soften and expand the valve seals. Check your oil level often. Use the higher viscosity oil and seal conditioner for your next oil change.

Things You'll Need

  • Floor jack
  • Jack stands
  • Socket set
  • Ratchet wrench
  • Drain pan
  • Drain plug O-ring
  • Oil filter wrench
  • Oil filter
  • Engine oil
  • Funnel
  • Oil sealant
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About the Author

Chris Stevenson has been writing since 1988. His automotive vocation has spanned more than 35 years and he authored the auto repair manual "Auto Repair Shams and Scams" in 1990. Stevenson holds a P.D.S Toyota certificate, ASE brake certification, Clean Air Act certification and a California smog license.