stuck water pump

I am trying to remove out the water pump. I am doing some preventive maintenance on it since it is at 150k miles and I am still on the factory pump. I bought myself a aisen pump that came with a metal coated gasket. I remove the pulley/tensioner and loosened 3 bolts and 2 nuts. The only problem is the pump is stuck on there. Must be some sealant of some sort. How can I get this thing out?

Edit: Ok, I tried getting a knife in there and it wouldn't budge out. Using a mallat hitting the edge of the knife. It does look like they are using a paper as a gasket which meant they used some kind of sealant.

 

looks like I have to wave the white flag on this one. The knife didn't work. I don't recall having some sort of maintenance on the pump, but I was a young guy who got suckered into agreeing maintenance work on certain things couple years ago. I put back all bolts and nuts and put in a new serpentine belt as well as put in new coolant. I will probably bring this in for a professional to replace the pump for me.

Before I do that, is there a way to remove really strong sealant? I watched the youtube video of the engine pump replacement and saw the removal of 3 bolts and 2 nuts. Is there maybe something I can do one more time before I really send it in?

I am also seeing a DTC code of B1462. I'm not sure if it's anywhere related or just me blasting the heat inside the car. Is it maybe got damaged when I spilled coolant?
edit: B1462 is probably a glitch since it is described as room humidity sensor circuit and my AC auto system changes just fine when I set low to high.

 

brought it into a new mechanic I'm trying out. Their shop used the water pump I bought and luckily I told them to use SLLC. I don't know whether they were going to use their own universal. I spoke to the mechanic and he said the my pump on the car I had wasn't OEM. gasket was paper and sealed with some sort of RTV sealant. Mechanic said he got a hammer to pound the pump out. Total cost was $180 for the mechanic to do the work and coolant, I covered the pump. I guess that is one disadvantage of having one tough sealant, it will be very difficult to remove.

 

I can't tell what is the brand name. Definitely not aisin. It has a Y-01, a 13 in a circle and a B1831 on the pulley holder above. You can see on one of the pictures where the leak is occurring. This being about 60-70k miles of life. You can see the sealant on the back which probably held on there like glue. The leak is small but the bearings were nowhere smooth as the OEM. I don't know whether this was me trying to crowbar the thing out or whether it's not turning well due to old age. the leaking does look small and I'm pretty sure I could have driven it some more, but it was probably a good time to change.

edit: how do you upload files? I get an error when I upload my pictures.

 

Here are some pictures of my leaking water pump, it was a very small leak considering it looks very dry.. about 70k old. Bearings making a lot of noise. I don't know what brand name, but paper gasket.