Keyword Question

Hi there,

First off, I'm new to this forum. I'm not sure if I'm posting this in the right section. If I'm not please let me know.

Anyways, I'm planning on building a niche site. This will be my first attempt at this, but after doing some research I feel confident I can make it work. I have a background in copy writing and technical writing, so I know I can create some really good content. I just need to make sure my SEO is done correctly so I can get some traffic.

I've found a keyword that gets some pretty good traffic and competition seems really weak from what I can see (average page rank is just 1.3, average moz rank is 2.5, average page authority is under 40 and all the sites have very few links). Ad competition and CPC are also high, so it looks promising.

I don't want to reveal the keyword, for obvious reasons, but the nature of the keyword will make it hard to use repeatedly in text. The keyword describes a problem that may occur with a certain appliance. For the sake of this post lets say the keyword is "car overheating".

The problem with the above keyword is that generally, when you talk about a car overheating, you use the word "is" between the two words (what to do if your car is overheating, when your car is overheating etc.) I have the same problem with the keyword if have in mind.

So, my question is, do I have to use the exact keyword (car overheating) or can I insert other words in between the two words and still rank highly for this word?

Sorry is this is a stupid question. I'm kind of new to SEO and keywords.

Thanks in advance for your help.