For the E30 A/C system, the main line-fitting O-rings are standard SAE sized. BMW confusingly identifies them by the O-ring’s approximate ID rather than the hose size and does so in mm. Because of the standard SAE sizing, you can can order oring kits much more widely and readily from suppliers like four seasons...
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I’ve found the E30 blower-motor retaining clip to be one of the most counterintuitive—and least documented—parts of the job. Here’s what you need to know. The clip behind the blower motor often falls out when the motor is removed, leaving it unclear where the rear end should attach. Despite appearances, it does not hook...
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Binary comparison of Bosch Motronic 1.3 173 and 525 ECUs, including coolant enrichment, cranking fuel and ignition, and every identified closed-loop idle-control table.
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A practical guide to the full E30 OBC: its displays, sensor inputs, trip calculations, speed warning, temperature alert, CODE immobilizer, coding plug, and built-in checks.
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How the E30 heater and air-conditioning systems route air, control refrigerant pressure, operate the auxiliary fan, and respond to the dashboard controls.
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A system-level explanation of the Bosch Motronic inputs, fuel calculations, ignition mapping, idle control, and emissions hardware used across several BMW E30 applications.
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The BMW ETK for the E30 is generally excellent, but it falls short when it comes to A/C part number references. This is especially true for M20-powered E30s, which were equipped with three different compressors – Bosch, Seiko, and Denso. While the Bosch and Seiko setups share the same A/C lines, the Denso configuration...
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It’s become increasingly common for owners to convert early E30 M20 cars to the later-style radiator setup. However, that conversion requires a long list of additional parts—new hoses, mounting brackets, water pump, coolant crossover, expansion tank, and more. In reality, this conversion is completely unnecessary. The trend has largely been driven by the assumption...
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Lloyd mats offers a trunk mat pattern for the E30 that fits well overall. It appears to include a bit of extra material near the battery tray area—likely to accommodate E30s with batteries mounted in the engine bay. It’s not a major issue; just a slight trim is needed, and everything fits perfectly. Details:...
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With the widespread use of NGK V-Power spark plugs (NGK 5077 – ZGR5A) in E30 M20 applications, it’s important to stay vigilant about their replacement intervals. These plugs feature a smaller electrode surface area, which, while great for ignitability, tends to wear faster. As the electrode wears down, the spark plug gap increases, which...
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