Blue smoke from exhaust pipe
Symptom: Blue smoke from exhaust pipe.
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Blue smoke from exhaust pipe
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Fault symptoms
Blue smoke from exhaust pipe.
Conditions
The following conditions apply for the fault symptom concerned:
Some cars produce unwanted blue smoke. There are two possible reasons:
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The check valve for the crankcase ventilation may be sticking, which means that engine oil can be forced out into the exhaust pipe, resulting in blue smoke.
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The flow of coolant through the turbo unit may be reduced, which results in the temperature becoming so high that the engine oil crystallizes (builds carbon deposits) around the turbine-side bearing. Over time these deposits reduce the oil flow through the bearing, which means that engine oil is forced past the turbine shaft seal and out into the exhaust pipe, resulting in blue smoke.
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Procedure
Carry out steps 1-15 only on engine variants B205R/235R.
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1.
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Remove the engine cover.
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2.
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Cut off the cable tie securing the check valve to the camshaft cover.
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3.
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Pull the check valve vacuum hose off the camshaft cover and the throttle body.
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4.
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Transfer the insulation hose from the old hose to the new one.
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5.
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Connect the new hose to the throttle body. Secure the check valve to the camshaft cover with a cable tie.
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Important
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The check valve must be turned so that the flow is directed away from the camshaft cover towards the throttle body, see the arrow on the check valve.
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6.
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Remove the crankcase ventilation hose from the nipple on the camshaft cover and remove the nipple from the cover.
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7.
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Clean the nipple for the check valve vacuum hose with a 2 mm drill bit. Blow with compressed air to clean.
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8.
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Fit the nipple to the camshaft cover and connect the hoses to the nipple.
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9.
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Check that the ignition key is in the OFF position.
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10.
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Remove the bolt securing the turbocharger delivery pipe mounting to the engine and the hose clip from the pipe attachment on the throttle body.
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11.
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Remove the turbocharger delivery pipe and move it to one side. Keep the O-ring.
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12.
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Turn the throttle disc to open position and wipe clean inside the throttle body, especially around the throttle disc sealing surface. Use a lint-free cloth moistened with
30 04 223 Electronic cleaner
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13.
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Grease the O-ring with acid-free vaseline and fit the turbocharger delivery pipe to the throttle body.
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14.
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Fit the bolt securing the turbocharger delivery pipe mounting to the engine and the hose clip to the pipe attachment on the throttle body.
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15.
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Fit the engine cover.
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16.
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Open the coolant expansion tank cap to release the pressure in the cooling system. Shut the cap.
Warning
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Take care if the car is warm. The coolant is hot and there is also a risk of burning yourself on the manifold.
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17.
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Place a receptacle under the car.
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18.
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Using a fixed spanner to hold the coolant pipe nipple in place on the cylinder head, detach the coolant pipe from the cylinder head, see illustration, and the pressure sensor mounting.
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19.
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Check that the coolant pipe nipple on the cylinder head is tightened and fit the coolant pipe with a new banjo screw and new gaskets in the cylinder head, see illustration. Fasten the pipe to the pressure sensor mounting.
Tightening torque, nipple in cylinder head 35 Nm (26 lbf ft)
Tightening torque, banjo screw, cylinder head 25 Nm (18 lbf ft)
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Important
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Banjo screw 51 25 406 must not be fitted anywhere else on the cooling system other than on the cylinder head connection.
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20.
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Top up with coolant as necessary.
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