Clearance Sale at the Black Market - S4-E1
Character mistake: When Hogan addresses him, Major Kiegel sends the girls away from his table by saying "Raus!" The word "raus" used as an imperative literally means "out" in the sense of "leave the room" - he would be ordering the girls to leave the tavern, or at least the tap room in this case. It's not correct German to use it to send somebody away from a table.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: After Kiegel shoots out the bulb the light takes a couple of extra seconds to fade out.
Clearance Sale at the Black Market - S4-E1
Revealing mistake: The Major goes to shoot out the light that the boys have turned on so Kinch can get the pictures. The first shot is angled too low to hit the bulb, but there is no impact on the front of the door's crosspiece; the smoke and dust comes from behind it. The second shot gets the bulb, but there is no muzzle flash, just sound. Also, there is no impact mark on the brick wall behind the bulb.
Clearance Sale at the Black Market - S4-E1
Continuity mistake: When Hogan is talking to Kiegel, Hogan's eyes are level as he looks across the table at Kiegel. After Kiegel says "Not good enough!", the camera cuts to a close up of Hogan, and he's now looking up as if the Major is standing. A moment later, the Major stands and leaves.
Klink vs. the Gonculator - S4-E2
Continuity mistake: In the barracks, as Lutz stands by the gonculator, Hogan's hand toys with the power cord. A second later, both his hands are at his sides.
Klink vs. the Gonculator - S4-E2
Factual error: They would never use their real names and whereabouts when talking on the radio.
How to Catch a Papa Bear - S4-E3
Factual error: In the tunnel Hogan loads a magazine into a US issue .45 pistol and points it at Myra, but he never chambered a round and didn't cock the hammer on the pistol. The .45 pistol in WW2 was single action. For a single action pistol to fire, a round needs to be chambered and the hammer has to be cocked manually before the trigger is pulled and the pistol to fire. (00:22:00)
How to Catch a Papa Bear - S4-E3
Continuity mistake: When LeBeau comes out of Hogan's quarters after feeding Newkirk chicken soup, he is holding a bowl with a spoon in his right hand. As he talks back and forth with Hogan and Schultz, the spoon jumps from in front of his thumb to behind it.
Hogan's Trucking Service... We Deliver the Factory to You - S4-E4
Audio problem: When Crittenden is figuring out military time he asks Hogan how much four and six are. The answer doesn't match Hogan's lips.
Hogan's Trucking Service... We Deliver the Factory to You - S4-E4
Deliberate mistake: When Schultz drives off with the motorcycle leaving the sidecar behind, you can see that the sidecar has been propped up. It has to be, or it would fall over. Sidecars, bringing only one wheel to the party themselves, can't stand up on their own.
Man's Best Friend Is Not His Dog - S4-E6
Revealing mistake: As Schultz holds Newkirk's hat during the search, you can see "Dawson" written on the inside band. This was to insure that Richard Dawson (Newkirk) always had the right wardrobe pieces.
Man's Best Friend Is Not His Dog - S4-E6
Factual error: When Hogan heads into Klink's flower bed to get the dog, you can see a modern steel water tank in the distance.
Man's Best Friend Is Not His Dog - S4-E6
Continuity mistake: The dog LeBeau is holding shifts position on his arm with each camera change.
Man's Best Friend Is Not His Dog - S4-E6
Other mistake: When seeing the tanks through the viewfinder, Carter's hands and the background are frozen, and the tanks are actually a clip of a wartime newsreel.
Man's Best Friend Is Not His Dog - S4-E6
Continuity mistake: Hogan's arms change position when holding the dog. First, his left is under the dog, and after the angle change, his right is under the dog.
Man's Best Friend Is Not His Dog - S4-E6
Other mistake: When referring to the barracks, usually Klink will refer to the buildings by their numbers (Barracks 2, barracks 3, etc.). In this episode, he calls the building "Building G".
Never Play Cards with Strangers - S4-E7
Other mistake: As Carter brings the German truck to a rough stop, in the closeup, you can see that although Carter and Newkirk lurch in the seats, the truck was already motionless.
Never Play Cards with Strangers - S4-E7
Visible crew/equipment: As Hogan takes off with Von Treger's car, the camera crew and equipment are reflected in the windows.
Color the Luftwaffe Red - S4-E8
Factual error: The medal Newkirk steals from the German officer in the pub is a Knight's Cross of the Iron Cross with Oak Leaves and Swords. There were a total of 148 presentations, most of them 1943-45. By 1942 (where the series is apparently set), less than 25 had been presented. That Newkirk should actually stumble across a wearer by pure chance is highly unlikely, that the wearer should actually "never miss it" as Newkirk states, is plainly impossible. Being the fourth highest ranking military decoration of the Wehrmacht, it would have been missed almost immediately - if not by the wearer himself, then by his fellow officers. (00:22:35)
Color the Luftwaffe Red - S4-E8
Revealing mistake: When the truck with Hogan and company pulls up to the Luftwaffe HQ, the camera pans to the right to look at Klink getting out of the side car. When the camera cuts back to Hogan and company, they shake as if the truck just stopped, but it can be seen that the truck was stationary.
Answer: It's a solitary cell. Steve McQueen, star of 'The Great Escape' is known as the 'Cooler King'.