The tire manufacturer imprints the max psi on the side wall of their tires. You shouldn't go higher than that maximum, but it is not necessarily the best pressure to put in.
Ford E350s use heavy-duty tires, typically with a max pressure of 80 psi. Unless you are carrying a very heavy load though, 80 psi will be more pressure than you need. My mechanic set my tires to 55 psi, and I typically air the rear tires up to 70 if I plan on running it full of people back there. (And if you're not running it full, you might as well just be driving a truck or a minivan).
Most vehicles have a recommended air pressure on a decal inside the driver's door frame. It's important not to underinflate or overinflate your van's tires, as it can lead to tire failure, extra brake wear, and even increased risk of rollover in an accident if your tires are overinflated or underinflated.
I need a diagram on where is the low pressure valve on a 1999 expedition
Means the air pressure in your tires is low
I don't believe there is
The 1998 Ford E3 50 low pressure air conditioning port is located on the air conditioning compressor. The low pressure port will be on the right hand side of the compressor.
What is it you want to know you have to be specific.
that you have low tire pressure. get more air in your tires and fill it to the numbers located somewhere near the driver's door
Air leaves a tire when the tire valve is open due to the pressure. The pressure outside of the tire is lower than the pressure inside the tire.
Air leaves a tire when the valve is opened due to the pressure difference. Since the tire has more pressure than the air outside, the tire air will escape until the pressure equalizes.
In between the radiator and the tire pressure gauge.
Air up your tires~!
Air rushes out because it is under pressure. Once there is no longer any pressure in the tire the air will stop flowing out. However there is still air in the tire it is just equal to the pressure outside.
Because the air inside the tire is under pressure. Gas always flows from a region of higher pressure to a region of lower pressure. As the pressure inside the tire is greater than the pressure outside, the air always comes out of the bicycle tyre.