BMW E30 cylinder head fault and inspection
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How can I tell if the E30 cylinder head or head gasket is damaged?
Signs include coolant loss, a sweet exhaust smell, bubbles in the radiator when you rev the engine, and mayonnaise-like oil. The symptoms alone do not prove the head has failed. A workshop can measure exhaust gas in the coolant, which confirms head faults.
How do I check the cylinder head for cracks?
Hairline cracks cannot be seen by eye. If there are no visible cracks, the head is taken to a machine shop for pressure testing and surface grinding, i.e. resurfacing. On the M10, straightness can be checked with a steel straightedge and feeler gauges.
What should I watch for when fitting the cylinder head?
Clean the head bolt holes with compressed air and make sure there is at least 2 mm of free space in the hole once the bolt has bottomed out. Set the engine to TDC and line up the camshaft timing marks before fastening the head.
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