Troubleshooting for the BMW 318i


1. Inspect the exterior of the 318 for any visible aftermarket modifications. Have the 318 badges been removed from the rear trunk lid? That is usually the first step, since most BMW owners do not want to admit they bought the cheapest one. If a rear wing has been installed on the trunk, then inspect the bolt holes for any signs of rust. Open the trunk to see if water has leaked through. Make sure washers have been used to help keep the grommets in place on the bolt holes. If water pools in the trunk, it can rust the body, frame and even get down to the fuel tank beneath.
2. Look at how the car sits on its suspension. If it rides low, then a lowering kit may have been installed. Inspect the struts for any cracks or signs of warping. Look at the rims of the wheels for signs of curbage. Curbage is when the sides of the rims hit curbstones and scrape off bits of metal. Look at the tires to see if any of them are running flat. BMW started equipping its cars with run flat tires in the 90s, but these were replaced by many owners with regular tires.
3. Open the hood and inspect the engine for any damage. Any cracks in the exhaust manifold could leak exhaust gases before they can get to the catalytic converter. However, many customers replaced their engines with bigger engines like the six-cylinder in the 330, or a Chevy small block. If so, inspect the engine mounts for any signs of stress and the bolts for shearing. If the engine is starting to work itself free of the mounts, then the mounts need to be replaced immediately.
4. Start the 318 and listen to the engine idle. If the firing seems erratic, then the direct injection ports could be clogged or the camshaft could have become unbalanced. In either case the engine needs to be repaired, but it would be cheaper to put in a newer, better engine than buy a new four-cylinder, since it is no longer made.