I want to major in engineering. If I minored in writing would it be too much?

It would be a great idea to have yourself exposed to both Engineering and Writing. Grow your logical thinking ability by taking the Engineering courses, you'll also get the benefits from the Engineering degree in a practical way. In the meanwhile, in your journey to make yourself a more interesting person with eyes for beauty of life, which in return helps your engineering skills in high-level, taking Writing as minor do helps a lot.

Take software engineers as example(I am one of them), people always hear from us saying that we want to change the world by coding. Taking the software engineering courses in college would be the practical way of learning how to implement the great ideas in your mind, but you also want to give more critical thinking to the ideas you have in your mind. Ideas do not exist in your mind in a perfect form at the very beginning, they keep changing during your thinking upon them. To polish the immature ideas until you make them the ideas that can really change the world, to accurately present the mature ideas in a better way to the world, taking the Writing courses would be my recommendation.

As for the workload for your college life in case you do take both, I do not think it would be a big problem as long as you are willing to commit reasonable time to both of them. In my opinion, you do not have to be a top-tire expert in both major and minor, the words "major" and "minor" themselves explains how you should deal with them. What concerns you probably be the fact that Engineering and Writing are two subjects that could not help each other during your study. Specifically, compared with something like Engineering + Science, Engineering + Writing looks less connected and one can not help you deepen your understanding for another. From my perspective, again, it should not be an issue. It could be a little bit tricky at the beginning but once you started diving deep into both of them, you ability of logical and critical thinking can be applied to both of them as well as your study skills. So don't worry and take both of them if you are hesitating right now, you will thank yourself in a long term.

Do it as long as you can manage the course load...and as long as you enjoy it!

As a tech writer myself, I absolutely think these two skills are a perfect fit and will get you far in life. I didn't take engineering courses in college (I stumbled into Salesforce Administration later on in life), but my love of writing and "figuring tech out" led me to where I am today. So go for it! And have fun. :)