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BMW N43 Engine Oil Pressure Control

BMW N43 Engine Oil Pressure Control Brand: BMW Engine: N43

Symptoms

The customer’s complaint is that there is a loud rattling noise when the engine is first started. The noise heard is louder than normal for a cold engine. Shortly after the engine starts the malfunction indicator light (MIL) illuminates. (This is the same as the “Check Engine” or “Service Engine Soon” light.)

If you use a scan tool, the BMW fault code is 30C1.

Causes

There are three possible causes for this condition:

  • The oil filter housing may be collapsed.
  • Oil pressure control valve may have failed.
  • The oil pump may have failed.

Repairs

  • Check that the oil level is okay as an initial check.
  • If all is fine, then connect the AssistPlus and run a Quick Test. You should see a fault code in the engine management system: 30C1 oil pressure control, static.
  • The next step is to check the oil pressure using the Diagnostic Request button on the AssistPlus. The oil pressure should be 1.5 bar at idle when the engine is at operating temperature.
  • This can also be confirmed by fitting a special tool to the oil filter housing and checking the oil pressure with a gauge.
  • If the oil pressure is low, remove the oil filter housing and check that the oil filter is not twisted or collapsed.
  • After confirming the oil filter is OK, remove the oil pressure control valve from the side of the block underneath the alternator and inspect it for signs of blockage or pieces of broken plastic.
  • If there are no signs of a blockage, replace the faulty oil pressure control valve.
  • If you find blockage or signs of plastic, remove the oil sump to inspect the oil pump. Below is an image of what you may find after the sump is removed.
  • If you find damage like this, carry out a full strip-down and replacement of the timing chain, chain guides and oil pressure control valve.
  • Inspect the oil pump and VANOS solenoids to assess the severity of the damage found. Replace components as necessary.