The air valves leak air and appear to need new air valve gaskets. Does anyone know where to get the gaskets?

Check the:
- Fuel pump pressure and regulating valve.
- Check the ignition system.
- Air leaks. (Throttle body gasket, idle air control valve shucked open, PCV valve open, vacuum hoses, gasket intake manifold, A/C VSV).
- Muffler.

Hi Kendal

Here are a few things to check, you may have already checked some of these.

*Electricity...Compressors will run best with full 115Vot 15AMP/Or 220V electrical supply from a circuit, over the shortest electrical cord as possible.

*Air Leaks..Place your ear close to the compressor and listen for air leaking, if you hear air that is not normal and means you have to locate and repair whatever it is that is leaking.
*Check the air unloader valve... The air unloader valve will blown out air when you turned off the compressor, that is normal.
But it should not have air leaking out of it all of the time. If so then it is faulty and in need of repair/replacement.
*Valves...If either the intake or exaust valves fail, breaks, or fails to seat, then your compressor will run 24 hours a day and never build up to the correct pressure for shut-off.
*Gaskets...Check to see if your gaskets have failed.
You could have a gasket failure between the pistons and you will never know it because it shows no external air leak.
If this situation happens then the air will only cycle between cylinders and never build up the correct air pressure.
One way to check the gasket is remove the air filter, then put your hand over the intake.
If correct then it will **** you hand against the intake.
If the valve or valves have failed then you will feel the air sucking in and blowing out.
*Piston Rings and Cylinder...The piston rings could be stuck,broken, or worn and not allowing the correct pressure to build up in your tank.
A worn cylinder will also contribute to the problem of pressure build-up.
*Pressure Switch...Check for air leaks at the pressure switch, it has a rubber diaphram that can fail and leak air out of the system.
Please take time to rate me
Bud

To solve the problem, first check the basic requirements for good function. The deflection of the belt should be 1/64 per inch of span between the centerpoint of the two pulleys. An example, if pulleys are 12" apart, the deflection is aprox 3/16". Next check for air leaks. With air in the tank at about cut out pressure, shut down unit and listen carefully for leaks (spray with soapy water) and repair as needed. Most likely leak is at the in-tank check valve. Remove the airline from the check valve and apply soapy water. If the check valve is leaking the pump with work extra hard to fill the tank. Clean the valve or replace if leaking. If no leaks, then suspect reed valves or head gasket. If reed valves or head gasket are leaking internally, the unit will take longer to fill and the discharge tube will be very hot. To keep track of the overall condition of your unit, you should know how much time it takes to reach cutout pressure. Ideal would be to time the unit when new then retest every month. If unit begins to take longer to fill, you know that a component is failing. Finally check that mounting bolts are tight and brace is not broken or cracked (some compressors have a very thin mounting plate causing the motor or pump to vibrate and the belt to wobble, a brace is added from the top of the pump to motor or motor mount). Good luck and let me know what you find.

Hi

Here are a few things to check.
You may have already checked some of these.

Electricity...Compressors will run best with full 115Vot 15AMP/Or 220V electrical supply from a circuit, over the shortest electrical cord as possible.

Air Leaks..Place your ear close to the compressor and listen for air leaking, if you hear air that is not normal and means you have to locate and repair whatever it is that is leaking.
Check the air unloader valve... The air unloader valve will blown out air when you turned off the compressor, that is normal.
But it should not have air leaking out of it all of the time. If so then it is faulty and in need of repair/replacement.

Valves...If either the intake or exaust valves fail, breaks, or fails to seat, then your compressor will run 24 hours a day and never build up to the correct pressure for shut-off.

Gaskets...Check to see if your gaskets have failed.
You could have a gasket failure between the pistons and you will never know it because it shows no external air leak.
If this situation happens then the air will only cycle between cylinders and never build up the correct air pressure.
One way to check the gasket is remove the air filter, then put your hand over the intake.
If correct then it will **** you hand against the intake.
If the valve or valves have failed then you will feel the air sucking in and blowing out.

Piston Rings and Cylinder...The piston rings could be stuck,broken, or worn and not allowing the correct pressure to build up in your tank.
A worn cylinder will also contribute to the problem of pressure build-up.
Please take time to rate me

The compressor will fill slowly if there is a leak at a fitting or pressure leaking back from the checkvalve. It will also fill slowly if there is a worn / broken reed valve/s and or leaking gasket in the head. Try easy test first. With compressor running and air filter off, spray soapy water on all joints looking for leak (also spray on head of pump to check leaking bolts /gaskets). If leaking, repair as needed. If no leaks are found with soapy water, stop compressor and listen for leak at the pressure switch unloader valve. If no air appears to be leaking from the compressor then most likely problem is with reed valves or gasket in the head. Remove head very carefully trying not to tear gaskets. Examine reed valves for broken parts and or burned /broken gaskets. If gaskets or reed valves are bad, the discharge air tube will be very hot. Repair as needed. Good luck

First things first, remove the fill valve, and the flush handle mechanism. This will give you plenty of room to work with the flush valve. Before installing flush valve lubricate tabs with plumbers grease. Now put on a pair of work gloves, pushed down very hard and turn the tabs should slide easy because of the grease. Remember do not alter the gasket, the gasket needs to be compressed to do its job. I know removing the fill valve and the flush handle seems like a pain, but there is no way to get your hands in the proper position to install the flush valve assembly.

The first step is to remove all the parts that are in the way of you being able to remove the valve covers. (Ex.: air intake, loose wires etc.) Then you will need to remove your valve covers (using basic tools) and be very careful to not let anything get on your lifters, which your valve covers protect. Once you have the valve covers off compare the new gaskets to make sure they are the right size. Then remove the old gasket and replace with the new one using a high temp gasket sealant (available at any auto parts store) to attach the gasket to the valve covers. Then tighten down snug and check for leaks after replaced. 

you will have to put another valve cover gasket on between each cylinder there is a round gasket between valve cover and cylinder head if you buy the valve cover gasket kit they will be in the kit .please rate this answer thanks.

To replace the valve cover gaskets on a Sienna: The front one is easy. The difficult one is the other side, closest to the firewall. You will need to purchase a new intake plenum gasket, when you buy the new valve cover gaskets, because you MUST remove the intake plenum to remove the rear valve cover. You can NOT get the back side valve cover off of the engine without removing the plenum. Trust me.
Hope this helps, and thanks for choosing FixYa.