Flush Oil - What Are They? Do I Really Need Them?

Many people wonder what Flush Oils really are, and what possible would be their function.' Do i need a flush oil? ' some many query. In this article we shall answer basic question to give you a better under standing of the function of Flush Oil to help you see if you really need them.

Flush Oils - What are they?

Flush oil are special compound oils that are very, very thin. They almost have the consistency of tap water both when cold and hot. Typically they are 0W/20 oils. Their purpose is for cleaning out all the gunk which builds up inside an engine.If the gunk in the engine oil gets too bad, the parts of the engine can get gummed up. An engine flush removes the gunk, which keeps the parts running smoothly. That in turn can make the engine more efficient, bringing the power and fuel efficiency closer to what the car had when it left the showroom floor.

In very old cars, however, the engine flush might clean these piston rings, valves, and other parts a little too well. Sometimes, the gunk acts as spackle in non-metallic parts like rubber seals that have cracked with age. Cleaning out the gunk exposes those cracks, and the weakness of those parts becomes apparent.

Apart from flushing some flush oils are used for other purposes. For example some hybrid vehicles now require 0W20, so if you're a hybrid driver, check your owner's manual. Also I believe Honda switched to recommending 0W20 in 2011 to meet their CAFE ratings (thinner oil gives less drag on engine parts which improves - fractionally - the mpg). If you look at 2010 models vs 2011, you'll see things like the Element and CR-V getting a tiny mpg boost in the official figures despite being the exact same car. They achieved this by remapping the gearbox shift points and dropping the cold viscosity rating on the oil. In reality unless you live in northern Alaska, or do an above average number of cold-start short journeys, 5W20 ought to be more than suitable.

Do I Really Need a Flushing oil?

Unless there's something seriously wrong with your engine, like you've filled it with milk or shampoo, you really ought never to need a flushing oil. If you do decide to do an oil flush, there's two ways of doing it. You can either use a dedicated flushing oil, or a flushing additive in your existing oil. Either way it's wise to change the filter first so you have a clean one to collect all the gunk. (This typically means draining the oil or working fast). Once you have a new filter in place, and the flushing oil (or flushing solution) in there, run the engine at a fast idle for about 20 minutes. Finally, drain all this off (and marvel at the crap that comes out with it), replace the oil filter again, refill with a good synthetic oil and voila! Clean(er) engine. For the curious amongst you, looking in the oil filter that was attached when you did the flush will be an educational exercise in the sort of debris that used to be in your engine.

Of course, like most things nowadays, there's a condition attached when using flushing oils. In an old engine you really don't want to remove all the deposits. Some of these deposits help seal rings, lifters and even some of the flanges between the heads, covers, pan and the block, where the gaskets are thin. I have heard of engines with over 280,000km that worked fine, but when flushed, failed in a month because the blow-by past the scraper ring (now really clean) contaminated the oil and ruined the rod bearings.

Is Diesel oil Suitable for flushing?

A question came up some time ago about using diesel-rated oils to flush out petrol engines. The idea was that because of the higher detergent levels in diesel engine oil, it might be a good cleaner / flusher for a non-diesel engine. Well most of the diesel oil specification oils can be used in old petrol engines for cleaning, but you want to use a low specification oil to ensure that you do not over clean your engine and lose compression (for example). Generally speaking, an SAE 15W/40 diesel engine oil for about 500 miles might do the trick