Replacing Heater Core

Good morning everyone. This is my first time logging on the site and already I'm impressed. I'm in the process of replacing the heater core on my '94 Trans Sport. My problem is removing the clamps from the 2 heater hoses. I assume they're the original factory clamps. I just don't know what type of tool to use to loosen the clamp so I can pull the hoses off. I've tried a 1" C clamp, I've tried a needle-nosed vise grip. But there's not a lot of room to work with trying to get a good grip on the hose clamps to remove the hoses. Does anyone have any suggestions?

..I've looked in the GM book but they do not mention the special tools required if any..then I tried to have a look at that for myself on the real car, and I really tried for several minutes and was not even able to have a glance at these clamps.... I guess you have already removed some items like power steering pump ...or do you get there from the wheel well ?
I wish I never get there...but just like that, I think I would use my Dremmel tool and cut the clamps then afterward I'd install more manageable hose clamps

Good morning everyone. This is my first time logging on the site and already I'm impressed. I'm in the process of replacing the heater core on my '94 Trans Sport. My problem is removing the clamps from the 2 heater hoses. I assume they're the original factory clamps. I just don't know what type of tool to use to loosen the clamp so I can pull the hoses off. I've tried a 1" C clamp, I've tried a needle-nosed vise grip. But there's not a lot of room to work with trying to get a good grip on the hose clamps to remove the hoses. Does anyone have any suggestions?

Even when you get the clamps off, the rubber pipe will not pull off the copper heater core pipes. They have been on so long they are stuck like glue and you have to cut them off. I removed the clamps with a small pair of mole grips then cut the rubber pipes to release them from the heater core. You may have to extend the rubber pipes when you refit the heater core.

When I refitted my heater core I cut back the copper pipes a little and made the connections inside the cab, so next time the heater goes its a lot easier to remove.

I have done this repair and it is quite a challenge. this is how I solved the clamp problem, because you really cant get a pliers into that very small area. I used a piece of steel brake line, a vise grips, some 1/8 inch wire rope and 2 small washers. this is how you make the tool; take about 6 feet of wire rope, hold it in the center so both end drop down. now, put the free ends through a washer, then feed both ends down the brake line. what you will have is the wire rope making a small 2-3 cm loop, then it goes down inside the section of brake line and the two ends come out the other end of the brake line.
Now, position the loop over both ends of the clamp then pull on the free ends on the other side of the brake line until its tight.
Now, slide the second washer up the free ends until it seats on the brake line. Next clamp the vise grips on the 2 free ends of the wire rope as close to the washer as you can get it. now this is how it works, turn the vise grips around and around to cause the wire rope to twist. it will then shorten and the loop over the clamp gets smaller, which will eventually squeeze and release the clamp!