When we go out and leave our 12 year old basenji in his crate he has started making this oder that is disgusting, it smells up him the crate and the house! Hellp

Anal glands? Impacted anal glands are "smelly" and also painful for the dog. What does your Vet say?

I was thinking the same thing as Judy, sounds like anal glands.
They smell FOUL, and some dogs need them to be emptied manually.

Anal glands are located just inside the dogs anus and every time the dog goes to the bathroom a little it of fluid is released.
If there is no fluid being released then it can build up and become infected.

Spending time in the crate concentrates the odor so that you really notice it.

I had a dog who cried in the crate if there was a storm. He drooled when he cried and it stunk terribly by the time I got home. He would be dry by the time I got home but I always knew if he had cried by the odor. He was an older dog with bad teeth so it got worse as he aged.

Dogs will release their glands if they are scared, under stress or the glands are too full.

You should get him checked just to make sure his glands are not plugged.. if everything is A-OK in that department, then he is releaseing them because something is scaring him.

Any other type of noticeable behavior? Does he not want to go to his crate? Does he pant?

Also.. what you're feeding him can impact his smelly moments. Bad food will create smelly dogs. He might not be able to help it.

He's getting older, things aren't working the way they use to. He might not have control. I know every time I take my 12 year old pointer on a car ride, she will release them. I've had her checked out, and she's OK.. Its just her. Its just something you have to deal with... another glorious thing that comes with owning an older dog :)