How to Treat Engine Oil Sludge Without Engine Disassembly

What do engine timing fault codes like 2A82, 2A87, 16396, P0012, 000018, p0011 p0018, P0014 all have in common? Even though they are for varying manufacturers, they identify the same type of problem – sticking, jammed, stuck-advanced, stuck-retarded or slow to react variable valve timing (VVT) systems. VVT systems allow vehicle manufacturers to design engines that perform well even with today’s tight emission standards. It’s imperative these camshaft phasers and adjustors, or VANOS on BMW, Camshaft magnets and solenoids, all move freely for proper engine operation.

Some failures are obvious because they produce knocking noises such as the Ford 4.6L and 5.4L engine knock. While other manufacturers have very little noticeable performance issue besides the CEL. Many times, these faults can be contributed to oil breakdown and build up inside these Variable camshaft systems. This causes small oil passages to become blocked and prevent oil pressure from moving various components necessary for engine performance.

Clicking noises from the valve tappets? Engine chain rattle on start-up? Check engine oil light on with valve timing fault codes? Sludgy deposits on the oil filler cap? Milky looking deposit on the dipstick?

These all could be signs of oil sludge build-up inside the engine crankcase and cylinder head cover.

There are a number of bad scenarios and some worst case ones to consider, but first of all:

Why does engine oil sludge up?

Previously, organic (non-synthetic) oil, with a recommended change interval of 3000 to 6000 miles, evaporated and burned, forming sludgy deposits if it was left in the crankcase unchanged past the recommended change interval. Synthetic oils are far more resistant to evaporation and oxidation, but certain factors can lead to sludging anyway: Unburnt or partially burned fuel in the oil (oil dilution); Compromised PCV system, Metal fragments and other impurities mixing in; dirt and debris adding to the soup.

The actual cause of oil turning into sludge may be excessive idling or very short trips; dirt and debris getting into the crankcase; condensation of moisture caused by the engine running cold; and hot spots on the innards of engine parts, baking the oil right onto the metal.

Deposits looking milky are often a whole other matter: A leaky cylinder head gasket can seep coolant into the engine oil, forming white froth and, eventually a milky substance builds up.

Now let’s look at ways that engine oil sludge can adversely affect engine life.

Modern engines are designed with extremely tight tolerances. Consequently modern oils are designed for low viscosity and high flow rate. You can see how sludge in the oil would be a disaster under these circumstances. The flow rate of the oil is certainly affected by lumps of sludge. Some oil passages may be blocked; wear and tear on tight-fitting components such as bearing journals and valve lifters can increase. The engine chain and sprocket can become lubrication-starved.

If the oil pump pickup is blocked or obstructed by sludge, we’re looking at oil-starvation in parts of the engine. Some recently designed engines utilize a variable-pressure oil pump. The function of these can be adversely affected by engine oil sludge.

Variable valve timing or VVT (known as VANOS in BMW models, VarioCam in Porsche, etc.) has been a feature of normal engine design for well over two decades. Many VVT systems use engine oil pressure to rotate a camshaft sprocket actuator varying amounts during engine operation. Clearly, if engine oil does not circulate correctly due to sludge, the VVT system fails. This sets engine fault codes and can lead to engine power and emission control problems.

If foam or a milky substance is present in the oil, corrosion and damage to internal engine components is inevitable.

For all these reasons, the first and most important step in maintaining engine health is to institute a rational oil change interval. As mentioned before, car manufacturers like to hype low-maintenance as a way to increase car sales, listing longer and longer oil change intervals. But they also specify shorter intervals for “severe use”. If you read the fine print, “severe use” turns out to be nearly everything you do with a car: Short-distance driving, frequent stops and starts, hot weather driving, long-distance driving, heavy loads. If you use your car for any of these activities you have to halve your oil change interval. So let’s get realistic: Let’s just say oil changes needs to be every 6000 miles or twice a year.

Next, you have to make sure the engine warms up correctly and operates within parameters. Usually, with modern OBD II vehicles, there is no chance that the engine will run cold or incorrectly in some other fashion without setting fault codes. Often, the malfunction indicator light (MIL or Check Engine light) illuminates. But it’s still worth checking the temperature gauge in an engine that has been running at least 10 minutes to make sure that operating temperature has been reached – that the pointer is in the middle of the temperature gauge.

If there is evidence of foaming in the engine oil (milky substance), you need to seriously search out a potential head gasket leak.

First of all, check the coolant for evidence of oil or other contaminants. Also, a radiator pressure test with the engine running will show if coolant is leaking past the head gasket into the engine oil passages. If pressure drops but there are no visible leaks, coolant could be ending up in your crankcase. Another test for head gasket problems is to use a Co2 tester such as the Bullseye Leak Detector from ATS. The Bullseye Leak Detector is designed to quickly and accurately indicate a head gasket leak at the radiator overflow neck with the engine running. If combustion gases are detected coming off the coolant, there is a head gasket leak, though in this case the leak is between a combustion chamber and a coolant passage. Still, if there is leak of that sort, there is also the possibility of oil and coolant mixing as well.

Another characteristic of oil sludging from carbon build-up is piston ring collapse. Low tolerance piston rings are designed to have as little drag against the cylinder walls as possible. When carbon or sludge builds up on the rings the can become compressed and allow oil to blow by thus causing oil consumption issues.

If you suspect former abuse, see evidence of sludge at the oil filler, hear chain rattle or valve lifter tapping, or if the engine oil drains very slowly during an oil change, suggest to the owner that it’s time to clean out sludge from the engine.

ATS Carbon Cleans 505CRO pour-in engine oil treatment breaks down carbon deposits and sludge from lubricated engine components.

Unlike other oil treatments 505CRO dissolves the carbon deposits from the engine into small particles and reduces problems with; sticking piston rings, sticking lifters, sticking camshaft phasers, sticking oil control valves, sticking timing chain tensioners, restricted oil screens (e.g. oil pump pick up). ATS Oil Pour-In Treatment increases engine performance while reducing engine oil consumption all within a 5-15 minute cleaning.

Using our 505CRO pour-in oil treatment can quickly and effectively repair common VVT issues caused by engine oil sludge. Listed below are common fault codes and the vehicles you may find them in. Before disassembling an engine to remove engine sludge from timing components, save time and money using ATS Carbon Cleans 505CRO pour-in oil treatment.

Generic Fault Codes:

  • P0011 Intake Camshaft Position Timing – Over-Advanced (Bank 1)
  • P0012 Intake Camshaft Position Timing – Over-Retarded (Bank 1)
  • P0014 Exhaust Camshaft Position Timing – Over-Advanced (Bank 1)
  • P0015 Exhaust Camshaft Position Timing – Over-Retarded (Bank 1)

BMW Fault Codes:

  • 2A9A Cam sensor, inlet signal invalid for synchronization
  • 2A98 (P0016) Crankshaft intake correlation value outside ref range
  • 2A82 intake VANOS jammed mechanically
  • 2A9B exhaust camshaft sensor signal invalid for synchronization
  • 2A99 (P0017) Crankshaft position sensor and exhaust camshaft, correlation value outside reference range
  • 2A87 exhaust VANOS jammed mechanically


  • P0011 Camshaft variable timing solenoid failure, Engine oil level is too low, The engine is not timed correctly, The engine oil does not meet the manufacturer’s requirements, Variable valve timing actuator failure, Worn timing chain
  • P0012 Camshaft variable timing solenoid failure, Engine oil level is too low, The engine is not timed correctly, The engine oil does not meet the manufacturer’s requirements, Variable valve timing actuator failure, Worn timing chain
  • P0014 Camshaft variable timing solenoid failure, Engine oil level is too low, The engine is not timed correctly, The engine oil does not meet the manufacturer’s requirements, Variable valve timing actuator failure, Worn timing chain

VW / Audi:

  • 16396/P0012/000018 – Bank 1: Camshaft A (Intake): Advance Setpoint not Reached (Over-Retarded)
  • P000A/000010 – Camshaft A (Bank 1 Intake): Positioner Slow Response Possible Causes
  • 000017 – Bank 1: Camshaft A (Intake)
  • P0011 – 004 – Retard Setpoint not Reached (Over-Advanced) – Intermittent
  • P000B – 008 – Slow Response – Intermittent

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