Today I was under my car under a lift and I was planning on changing my sender. And I was doing it on a naval base using their tools. Well the tool that they had looked like a sparp plug socket like they are supposed to. But it would not fit, I had no room between the top of the sender and my fender well to put it on. So I heard that people use vice scrips, so I clamped on to the medal tube not the bolt on the bottom and it was turning but it would not budge the bolt. So is there a better tool to use,or another way? I have headers also so that made it difficult. And also since I was twisting that medal tubing is there a seal that I could of broken to make it leak oil. I just did it before work and have not had a chance to look. I am just worried that oil will shoot out that, but I dont know. I need some help with what tool to use and if it will leak oil?

Did that just last weekend. Get a BIG set of vice grips and clamp on just the tips to the side of the hex nut on the sender. It's gonna be at an angle and you'll get very little movement before the handle hits something, but it will move it. I know there's not much room to get tools in there with the oil filter housing in the way. Fortunately, it's not in with much force and doesn't often "seize" in place, being constantly submerged in oil. Having the oil filter off won't buy the tool any more room but it will help you get your hands in there.

The replacement unit, if it's like mine, will have the hex nut out about 1/2" further which will make it much easier to get an open-end or adjustable wrench around it for installation. Again, spark-plug tight, not gorilla-tight.

Well it looked like the new is also a smaller hex nut. Was that the same case as yours? Guess it does not matter. But since I did twist the tubular part will it leak oil out of the seal that I might of broken?

It may leak but it's not gonna spray everywhere unless you actually broke the sender off. At most you'll get a steady drip when running.

Is it anything to worry about? Because I do not know how long it will be untill I can get to it again.

Probably not

if - you don't mind maybe smelling burning oil through your vents.
You don't mind maybe adding oil here n there/checking the dip stick daily, or take a risk of the hole expanding cause it is under pressure of the oil.

Personally, I would get it fixxed no matter what it took, just knowing there is NOTHING wrong goes for a better n a more rested mind

Why are you replacing the sender?.. OIl gauge or idiot light not working?
What Model/year is your car?

The replacement sender I installed did have a slightly smaller hex nut than the original, yes. You've obviously got an eye for details, just like me, if you noticed that!

is this the one by the distributor or right above the oil filter? if its above the filter u can just use a good wrench on it, i replaced one on a 85 monty carlo and it came out no problem and same went with the one on top by the distributor u just need a big socket but u might be hittin the distributor so ull have to find a way to get around it.

Sorry it took so long, I had to leave work. But its the one by the oil filter. I have 91 so I do not have one by the distributer. I tried ever damn tool there was. I think I am going to go up and try to see if Dyno Don can pull it off. And thanks for replying about the smaller hex. I know now that I have the right part. I do smell and little oil and it leaks on new driveways and the get upset. But I would like to get this fixed asap.