The E30 is a 3-series. The E28 is a 5-series. These are BMW internal production codes for a particular body style.
This article explains why, even though we’re focused on selling 3-series parts, we have this weekend added 5-series support to our parts database.
To quote Wikipedia: “The ‘baby six’ engine found in the 520i, 525e and 528e models is known as the M20, a 12-valve SOHC inline six-cylinder design … 2.7 L in the 325e and 528e models.” and “This engine is known as the ‘ETA’ engine. “
So, with the exception of the 1988 model, which is internally different, the 528e has essentially the same engine as the 325 and the 325e.
The 528e is more pricey to repair and maintain, so its desirability is slowly but surely decreasing. Whereas the E30 has a large group of people who are determined to keep their cars on the road and are encouraged by the car’s relative simplicity, the E28 doesn’t have as strong a following in that respect. We are seeing symptoms of this first-hand. The junkyards seem to have a proportionately large volume of E28 cars relative to E30 cars, even though there are more of the latter around.
So, as of yesterday, our business model includes buying E28 cars with the M20 engine, because these engines (and actually, the transmissions too) as well as related parts can be sold to E30 owners.