Blue exhaust smoke
Symptom: Blue exhaust smoke
Fault symptoms
Blue exhaust smoke
Conditions
The following conditions apply for this fault symptom:
There are two causes.
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The check valve for the crankcase ventilation can get jammed and cause oil to be forced into the exhaust pipe, resulting in blue smoke.
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Under certain conditions, the coolant flow passing through the turbocharger can be hindered. This results in the temperature becoming so high that the oil will crystallize (carbonize) around the bearing on the turbine side. The carbonization gradually blocks the oil drain from the bearing, which results in oil being forced past the turbine shaft seal and into the exhaust pipe resulting in blue smoke. If the carbonization is allowed to continue for a longer period, the turbine shaft will jam, thus resulting in permanent damage to the turbocharger.
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Diagnostic procedure
If the car has a VIN in the interval Y3015850-Y3041906, only steps 1-6 and 11 should be carried out.
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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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Detach the vacuum hose from 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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Attach the new hose to the camshaft cover nipple and to the throttle body.
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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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Fasten the check valve to the camshaft cover using a cable tie.
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7.
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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 exhaust manifold.
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8.
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Position a receptacle under the car and remove the coolant pipe from the cylinder head and pressure sensor bracket.
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9.
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Make sure the coolant pipe connection nipple on the cylinder head is tightened and fit the coolant pipe with a new banjo screw and new gaskets in the cylinder head. Attach it to the pressure sensor bracket.
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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10.
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Top up with coolant if necessary.
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11.
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Warm up the car and check for any blue smoke under load.
Was there blue smoke?
YES. Continue with Step 2.
NO. The car has been rectified.
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Diagnostic procedure step 2
Change the turbo. See
Turbocharger, 4-cyl.
