Worst case scenario - There are a couple things that come to mind, one being IBS (irritable bowel syndrome) and the other would be a pancreatic deficancy.

Their tummy will also growl if they have an intestinal parasite problem that has not been diagnosed.

If this continues, you should see the vet for a fecal exam and a general look-see to see what's going on.

Many people complain about this after their dogs have eaten grass. And you will often see this noise if a dog has consumed garbage or eaten something that has not agreed with them. If you suspect this, you can try to ease some of the gas pain and stomach upset by offering her only a bland diet of only boiled chicken and white rice until she is past this spell. This is often soothing to the stomach.

Some dogs can get some relief with some Zantac as well. You should talk with your vet about this kind of therapy.

For the diarrhea, I would suggest that you switch him over to a bland diet of ONLY boiled chicken and white rice for the next few days. And see your vet if this does not resolve.

Let me know if you still have questions.