The video shows officers bashing at the windows of the vehicle, before they take the dog out and give it water and taking it away.
The video follows warnings from West Midlands Police about leaving dogs at home rather than taking them in cars on hot days.
The film was taken on July 20, and shows the animal being cared for by two officers and four other people after being taken out of the silver van.
A resident who did not want to be named said: “The dog was left by its owners for hours.
“Police forced entry to rescue the dog and found a make shift kennel at the back of the boot.
“The dog was responding very faintly and was provided with water. The dog suffered from heatstroke and the attending female officer was very upset whilst attending.
“The dog was lethargic and not very responsive. Water was poured on the dog and it was also given a lot to drink. It showed better signs of life afterwards.”
West Midlands Police were contacted about the incident in Hunters Road, Lozells but declined to comment further.
The police’s general advice is to leave dogs at home when going out even for a short time on a hot day.
Anyone who sees a dog in a car on a hot day thought to be suffering or in danger of suffering is asked to contact the force immediately.
But residents are warned that breaking a window could result in them being investigated for criminal damage.
This can be done by using the website’s Live Chat facility on west-midlands.police.uk or via 101.
Birmingham City Council’s website at www.birmingham.gov.uk allows residents to report dog welfare issues online, and also suggests contacting the RSPCA for other animal welfare problems.
The site advises that those responsible for dogs must provide a suitable environment and diet, housing with, or apart from other animals, an ability to exhibit normal behaviour patterns and protection from pain, suffering, injury and disease.