Other mistake: During the paint factory fire, when Engine 2 rolls up, we can see the red, large, rectangular vinyl material that is adhered to the front of the engine, with the company number printed on it. There's also vinyl material adhered to the top of the cab as well as the back of the engine with nothing on it, presumably covering the engine company's real number.
Other mistake: When Squad 51 is dispatched to the possible heart attack, while Chet’s at the base station responding to the dispatcher, the lightbar atop Squad 51 has nothing covering the chrome, but en route in the close up there's black tape covering much of the chrome trim.
The Promise - S3-E11
Other mistake: At the very end, when Roy is cleaning the windshield while John's fiddling with the squad’s radio mic, the spray can on the hood of the squad has tape covering the brand name.
Other mistake: When Dixie's on the phone with the suicide attempt, Dixie tells her the date of her own birthday, hoping to get the caller's birthday in return. Then when the caller tells Dixie that the month of her birth is February, while Brackett's listening, they don't contact Early who's with the senior data analyst with that crucial information to help narrow down her identity faster, which was the whole point of Dixie trying to get that information from her.
Other mistake: During the fire at the horse ranch, when Engine 40 rolls up we can see that the engine company's number is covered atop the cab, and the large, red rectangular vinyl material that's adhered to the back of the engine with nothing on it. Presumably covering the real engine company's number.
How Green Was My Thumb? - S3-E17
Other mistake: When Station 51 is dispatched to the fire at the winery, just as Squad 51 rolls up, in this semi-closeup we can see that it's Roy driving and exiting the squad, and also that it's actually Randolph Mantooth's double exiting the squad and getting the drug box from the side compartment. Also fun to note the difficulty the double had just opening the squad's door.
Heavyweight - S3-E5
Other mistake: When Chet is preparing the lasagna, then tells Johnny that he's preparing 'rutabaga delight' especially for him, the green container of parmesan cheese has tape covering the brand name, though it looks like it's the Kraft brand.
Cook's Tour - S1-E4
Other mistake: When Johnny and Roy visit the woman they assisted in delivery, they go through the ER's double doors opposite receiving, as if heading upstairs to her room, and soon she even comments that the baby was brought up to her from the ER. Then, when the guys leave her room, Roy pushes open the door on the right, and we can see the ER's treatment 5 and the silver cabinets right up the hallway, so we know that Roy and John were actually in the room just off to the side of the nurses' station in the ER.
Other mistake: When all the guys are sitting around the table discussing the paramedic problem, while Chet is looking in the fridge for the ketchup, we can see the milk containers on the door have their brand names covered.
Other mistake: While Roy's in the ambulance with the woman who fainted, when she holds out the bag of potato chips, we can see the large brand name on the front of the bag is covered with red tape in two places. Though they neglected to cover the small 'Lays' brand name on the side of the bag.
Other mistake: At the start, while Johnny is cleaning the oven, we can see that the oven cleaner spray can has tape covering its brand name, and anything else on the can that gives away the name of the brand.
Other mistake: The USC game that Roy and Johnny are assigned to is supposed to be a sold-out game, but in closeup shots of the crowd around the guys, we can see that around the small crowd of extras used during the shoot, the seats are empty.
Other mistake: During the surgery on Brackett's father, after the closeup of the anesthesiologist there is a closeup of the Bird's Mark 4 unit, then a closeup of the bellows housing showing inflation and deflation, but on the bellows unit it reads "Animal Anesthesia Ventilator" made by Bird.
Other mistake: When Station 51 is dispatched to 'man trapped in vehicle', we can see the real Station 127's vehicle is still parked inside the apparatus bay, near the rear bay door.
Daisy's Pick Blind Date - S4-E7
Other mistake: When dispatched to the fire in the theater, the companies called are Station 51, Engine 85, and Station 36, but at the scene of the fire we see Engine 9 roll up and also see firemen with 19 on their helmets. These are shots from previous episodes including 3x7, "Promotion", when Roy and John rescue the security guard at the structure fire.
Other mistake: After Station 51 is dispatched to the 'vehicle accident with injuries', in the exterior shot as the squad and engine roll out, we can see the real Station 127's vehicle is still parked inside the apparatus bay, near the rear bay door.
Other mistake: When Station 51 is at the scene with the electrocuted man, he's dangling from a rope below the second stem of the letter H, in the large sign which reads "HOTEL", above the striped awning. In the shots from above the sign, looking directly down as they set up the ladder, we can see the letter H and the awning, but the dangling man is simply not there in the shots from this perspective, even though we should be able to see him.
Family Ties - S6-E16
Other mistake: Before the fire in the patient's room, which is caused by liquid shorting out the clock radio, we can see the tape covering the brand names of the baby powder and the clock radio.
Inventions - S3-E22
Other mistake: When Station 51 responds to the incident of the man who fell through the ceiling at his mother's house, the footage of the squad and engine pulling up to the curb of the house is from episode 3x15, "Messin Around", when they rescue Old Bill after he's collapsed in his house.
Other mistake: After Johnny gets hit by the phantom in the apparatus bay, Station 51 is dispatched to an unknown type rescue at 617-1/2 Kimball Rd, and before the dispatcher even gives the address, Mike has already located the area on the map with his finger.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.