To Flush or Not to Flush #OilChat 66

The question Should I flush my engine? is often asked.

The short answer is it is very unlikely that your engine will ever need to be flushed if you change your oil regularly or as recommended by the manufacturer and use a good quality oil from a reputable supplier.

Whenever the words ‘Engine Flush’ are mentioned one can expect concern from many mechanics and automotive technicians. They will most likely recall horror stories about engine flushes that have gone terribly wrong resulting in engine damage and they will have good reasons why engine flushes should be avoided. They are right to feel this way as older methods of doing engine flushes were a high-risk gamble. You only did an engine flush as a last resort and performed it with utmost care when the engine had been so horribly neglected that there was no other choice in the matter.

An engine flush involves taking out some of the oil, adding a flushing additive, letting the engine idle for 10 to 15 minutes and then changing the engine oil and filter. Traditional engine flushes were formulated with a solvent and/or a strong detergent. The problem is that the chemicals in such flushing additives can damage engine seals, bearings, turbochargers and other oil-lubricated components. Volatile solvents may also ignite and even explode inside the engine.

Almost every vehicle manufacturer has released technical service bulletins or other documentation in which they warn against performing crankcase flushes. Not only is the service unnecessary, they say, but it can also damage your engine. If your vehicle is under warranty and you experience an engine failure, the servicing dealership will most probably ask you to produce your service records. If your maintenance receipts include a record of performing a crankcase flush, most manufacturers will deny the warranty claim.

It is true that sludge, varnish and other gunk can build up in neglected engines. Engine sludge is made up of oxidized motor oil, dirt, soot, water vapor, combustion gases and other contaminants. Proponents of engine flushes may show you photos of extreme engine sludge as depicted on the right. The fact is that no well maintained engine ever gets anywhere near this bad, and if it does, the damage is already done – the engine will be worn out and beyond repair.

If you are concerned about the condition of your engine the following symptoms may be an indication of the presence of sludge inside the engine:

  • Noisy hydraulic lifters or valve tappets – metallic clicking sound
  • Low oil pressure
  • Oil warning light stays on
  • The oil drains slowly when drain plug is removed
  • Presence of dark greasy substance on the dipstick and inside oil filter

You can also check for the presence of sludge by shining a flashlight inside the engine. Simply remove the oil cap and use the flashlight to check for accumulated sludge inside the valve cover. In a normal engine all the components should be covered with oil, but you should still see the metallic parts glistening in the light. If you see thick tarry deposits inside the valve cover, you might be dealing with a serious case of engine sludge.

In defence of engine flush, we must add that the latest detergents used in some products available on the market provide a much safer way of eliminating contaminants from engines and avoid possible problems. Having said that, we must also stress that lubricant manufacturers blend their engine oils with specific additives to keep engines clean on the inside. High quality motor oils contain sufficient detergent and dispersant additives to take care of all those ghost riders inside engines.

While varnish and sludge can build up in a poorly maintained engine, this normally never happens when your oil changes are performed regularly. The vast majority of engines on the road are quite clean on the inside and will stay that way as long as their maintenance is kept up. Change your oil regularly, use a quality oil and filter and you will be just fine. Even if your engine has been a little neglected for a while, Q8 engine oils contain all the additives required to safely clean your engine during normal drain intervals.

To find out more about Q8 high quality engine oils phone 011 462 1829, email us at  or visit