A low coolant level could cause the temp gauge not to read correctly. A faulty temp gauge sending unit could also be the cause. The coolant leak, you would have to find the source of the leak to determine the cause.
A gauge does not idle, please rephrase and re-ask the question.
The high pressure line is a high pressure hydraulic line. The can leak from the attachments to the fittings. The will leak where the line is damaged Or if it as a very old line they can crack.
The gauge line is secured when the refrigerant cylinder is on the scale while transferring refrigerant to prevent the refrigerant from leaking out. If the refrigerant were to leak out, it would cause the scale to become inaccurate, and it would also be a safety hazard.
If you run the transmission low on fluid you can cause damage. Fix the leak.
There are several things that can cause your fuel tank to leak. The most common cause is a hole in the fuel tank. A loose fuel line can cause the fuel tank to leak.
Leak on drain line above floor level
A leak somewhere in the system.
A broke fuel line can cause a 1995 Beretta to leak fuel into air filter assembly. An exhaust leak can also cause this issue.
A small hole in the fuse line would cause a gas leak on a 1994 Honda Accord LX. In addition, a hole in the actual fuel tank would cause a leak.
Low coolant due to a leak is a very likely cause.
Usually, but not always.