"Squeeze" type hose clamps
 

Laugh at me later, but I need to change the small 5/16(?) heater hose (bypass, possibly), approx. 7 in. long underneath the 3/4 in. diameter heater hose running to the firewall/heater core, next to the manifold. The hose clamp requires pliers to squeeze the "tabs" together to loosen the hose, but difficult to get a firm grip, and is so old it is embedded in the hose. Someone must know a trick to these clamps, or a way to break them, because I am having difficulty just getting to the tabs. I need my car! Suggestions? I am on my own here with no way to get to the auto parts store, and borrow those special pliers that probably, will not fit in the cramped space.

Thanks

I wish I knew of a "trick" but it seems there isn't one. All you can do is squeeze those tabs together and try rotating it from side to side. Maybe if you got a different shaped pliers, like a long, thin needle nose, maybe curved, you would have better luck.

Part of what and how you do it depends on whether you are trying to save and reuse the hose.

And please don't post in multiple threads. Stick to this main thread, it will be better.

If the photo above isn't clear, there are angled tip needle noses that are about 12" long which should allow you to get to the fittings.

Also, if the car is operational, run it for a little bit to warm the fittings and hoses ... they'll be easier to remove.

Use the curved pliers that CSAR mentioned, that curve can make ALL the difference when youre trying to find the right angle. I try to replace with worm hose clamps when I can, usually easier to get a 8mm on one of those than it is to wrestle the squeeze clamps in a tight spot. If space isnt an issue, I like to use vice grips for these types of clamps, as having the tool lock in place and keep the clamp squeezed on it own lets you more easily get your hands on the clamp itself and pull it free without it tighening again.

The problem is trying to rotate the clamp, because the hose swelled at the clamp, and cannot break it loose. I cannot believe this clamp is kicking my a**, and I have not begun to attempt the other side that I can only feel, but cannot see. I would need to remove the 3/4 heater hose above it to see it, and is rusted at the end due to the water spraying from the leak. It, also has the same clamp, and imagine the rust will make the hose difficult to remove.
I will NOT reuse these clamps if I ever get them off. I might, have to invest in pliers specific to these clamps.
One more question, do I have to drain the radiator for this one, tiny hose? I think, yes, but someone else said no.

Spray a lubricant, any lubricant, liberally on the clamp. When you release pressure it will weep under it and allow better rotation.

Yep. Been there just like you. It helps a lot.

Be very careful if you attempt to use regular worm gear clamps on the plastic heater core hose connections. A little too much pressure and you get to watch those old brittle plastic heater core connections crumble before your eyes.

I bought the curved nose pliers shown in your post, but they were too curved to fit. Luckily, my friend had these old rusted pliers that worked better, but still, was no easy task requiring some ingenuity (grab whatever works within reaching distance of your free hand, because letting go might not find that sweet spot, again or quickly). That short 5/16 hose better outlast the car, because I do not want to do that, again! Actually, I would not have to, exactly, because I replaced those spring/squeeze clamps with, (do not judge me), the smallest screw-type clamps. Much easier to get to, and did not overtighten. These pliers made all the difference!
https://cimg9.ibsrv.net/gimg/maxima....58e0ab87b3.jpg
Long-handled
https://cimg3.ibsrv.net/gimg/maxima....33f17ac2e2.jpg
Slight curve

Good deal. You did it!