Aluminum Engine Blocks

Aluminum blocks are more likely to suffer damage from overheating. Aluminum also looses about 20% of its strength at temperatures over 200 degrees. Aluminum costs about four times what iron does. There's also problems with contamination of coolant. It turns acidic over time and is rough on aluminum. I think that we've made a lot of advances in alloys over the last few years and I won't be surprised to see more aluminum used in engines as the big three struggle to meet fuel economy standards.

In our vehicles, we've had cast iron blocks with cast iron heads, cast iron blocks with aluminum heads, aluminum blocks with aluminum heads.

We haven't had a problem with any of them. I would say modern manufacturing and design has overcome any problems with aluminum blocks or heads many years ago.

Years ago I recall the GM Vega aluminum block had a number of problems. But that was back in the 1970's and we've come along way in design and manufacture since then.

As you mentioned the GM gas engine, remember that the heavier duty GM Duramax diesel engine has aluminum heads and block. I can't recall any issues arising from this engine, due to the use of this material.

I think those that maybe concerned about the use of aluminum engine blocks....might be basing their opinion, on older ideas about the unsuitability of aluminum as engine block material, that was prevalent during the days of the problem prone Vega aluminum block.

Nowadays, not an issue, IMO.