Sunday, July 31, 2022

the design flaw of the Fiero

The driveline and rear suspension were actually the front wheel drive components ripped out of Citation ... and "flipped around backward

 The "Iron Duke" was a heavy 92-hp OHV 2.5-liter four-cylinder unsuitable for a high-revving sports car. The engine was slightly too large for the engine compartment, so the engineers reduced the size of the oil pan.

According to one authorized GM parts dealer, this caused the engine to run low on oil, which made it easy to overheat the engine, leading to fires. Yet, as reported by Hagerty, the oil issue was due to an "incorrectly marked dipstick" and the owner's manual listing the oil pan as three-quart instead of four-quart. 


  1. The "Iron Duke" was also the engine they put in the Vega, and was the original "destined to fail" engine that marked car makers designing obsolescence into their product. The fact that it continuously failed in the Fiero was not surprising, although the electrical problems the Fiero had were far more prevalent from Day One of ownership than the engine or transmission problems, which took 40K-60K miles to show up...

  2. The Vega engine was an aluminum engine block and was it's biggest failure point. The aluminum used was a high silicon alloy that was supposed to be long wearing, but it was anything but and the pistons and rings running directly in the aluminum bores quickly wore the blocks and started drinking oil at low mileages. When I was in trade school our auto shop had a cottage business boring and sleeving Vega blocks. We kept an inventory and swapped them out so the next set of students could learn while rebuilding the cores. In comparison the Iron Duke was a pretty good motor. A little trouble with oil leaks from the valve covers in the first couple of years, but very reliable after that. Just not a power house... it was rare to get highway speed and air conditioning at the same time. GM also sold a lot of them to AMC to install into Jeeps.

  3. The 4.9 Cadiliac aluminum V-8 fits right in light it was designed for it .

    and GM finally made a V-8 Fiero,
    its called the new Corvette,