Engine Sludge build up: The Black Death of sad engines!

Image from: www.tunemytoyota.com

Engine sludge build up used to be better (Or more sensationally) known as “Black Death”; probably accurately describing the appearance an effect it has on an engine, if not rectified in time.

Basically what happens is the oil oxidises and becomes contaminated to the point where it thickens to form a sludge and changes colour. The high viscosity, in turn, leads to the oil pump not being able to pick up this sludge from the oil pan; causing oil starvation.

What causes engine sludge build up?

The most common factors in engine sludge build up are a combination of mineral oils oxidising, a lack of maintenance by the car owner and harsh driving conditions. However, a 2005 Consumer Reports article discovered that some engines from Audi, Chrysler, Saab, Toyota, and Volkswagen appear prone to engine sludge build up, almost no matter how often the oil is changed.

Typically engine sludge build up would be caused by an overheating engine oil, oil that hadn't been changed for 20,000 miles of stop-go city driving, and regular cold starts.

Under these conditions full synthetic engine oils are far more stable and don’t oxidise as rapidly. The additive packages are also designed around these severe operating conditions.

How do you prevent engine sludge build up?

There are no hard and fast rules for curing engine sludge build up. If it's really bad, flushing the engine might be the only cure, but that could also cause even more problems. If flushing the engine results in bits of sludge getting lodged where they can do more damage, you're actually worse off.

So if a cure’s not guaranteed, what about prevention? Well this is somewhat easier:

• Regular oil changes (As prescribed by the manufacturer, and bearing in mind the severity of the operating conditions) 
• Use of a good quality fully synthetic motor oil. 

When is engine sludge not sludge? 

Easy; when it's an oil and water emulsion from a leaking or blown head gasket! If this happens, you get a whitish cream coloured engine sludge build up on the inside of the oil filler cap that looks like vanilla yoghurt or mayonnaise. The cap is typically cooler than the rest of the cam case and so the oil/water mix tends to condense there.

If the underside of your filler cap has this sort of deposit on it, chances are the engine has a blown head gasket. A surefire way to confirm this is if your oil level is going up and your coolant level is going down.

Note: There is one other possible cause for the mayonnaise: a blocked scavenger hose. Most engines have a hose that comes off the cam cover and returns to the engine block via a vacuum line. This is the scavenger hose that scavenges oil vapour and gasses that build up in the cam cover. If it's blocked, you can end up with a build up of condensation inside the cam cover, which can manifest itself as the yellow build up inside the filler cap.

Although oil can’t overcome mechanical maladies, such as leaking head gaskets or blocked breathers; a good synthetic engine oil can certainly control engine sludge build up.

Don’t take a chance that could cost you a fortune: The Synthetic engine oils produced by Habot Synthetic Lubricants are formulated to withstand harsh operating conditions that typically lead to engine sludge build up.