Vacuum leak
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Vacuum leak
I am a newbie here and it has been since the 80's that I have attempted to do any work on a vehicle.
Can some one tell me to how do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents.
Please excuse my lack of knowledge.
I have an 2000 F150 with the large engine with about 112,000 miles.
Any advise or help is most appreciated.
Thank you,
HerbW
Can some one tell me to how do I find a vacuum leak and where is my vacuum canister. I am assuming that it is a vacuum leak for anytime my engine has a load on it the air stops coming out of the dash vents and goes to the defrost vents.
Please excuse my lack of knowledge.
I have an 2000 F150 with the large engine with about 112,000 miles.
Any advise or help is most appreciated.
Thank you,
HerbW
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Joined: Sep 2013
Posts: 665
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nota problem.. But i can tell u this, u dont have a vacuum leak as far as your motor gos. Vacuum is most noticeable at idle, because thats when vacuum is at its highest due to the throttle body being closed. And when u lay in the gas that throttle body opens to let air in and then when vacuum gos down. And if this was the case youd have much bigger problems. But i think i understand ur problem with the vacuum control vet system. What you gota do is find out which vacuum pot is used to open and close the vent to your defrost and dash. Then test them to see if they can expand and retract when u put suction to it or trais down those vacuum lines for a leak. Theres all the input i got good luck,
Hotshot
Joined: Jan 2004
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From: St Louis
The vacuum reservoir is inside the right front fender.
You do have a mild vacuum leak in the vacuum system that services the climate control. Most common is a cracked or split line near the battery. If you have the electronic climate control, the o-rings in its solenoids often cause the problem.
The individual vacuum motors very rarely are the problem, so spend your time on the common stuff first.
You do have a mild vacuum leak in the vacuum system that services the climate control. Most common is a cracked or split line near the battery. If you have the electronic climate control, the o-rings in its solenoids often cause the problem.
The individual vacuum motors very rarely are the problem, so spend your time on the common stuff first.
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Joined: Aug 2003
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From: New Jersey
Same problems
I thought I just posted a similar question about 15 minutes ago but I don't see it here. Just as well because I was going to say ignore it because I was wrong.
I'm trying to trace the vacuum line back to the blend door motor to make it operate properly. Starting at the battery box and the small canisters attached to it, I have 19 lbs of vacuum. There are 2 small valves on the firewall near the battery box. They have two (2 each) vacuum lines going into them and each valve has an electric plug on it. I tested the voltage and 3 of the 4 wires have 13.8 volts while on had only 1.3 volts. Is this right or do I have a problem with on of these valves or is this voltage correct, meaning I still have a vacuum leak somewhere.
Once I get an answer to this I can move on to the next phase.
My problem is a lack of vacuum going to the blend door motor. I put a hose on it and drew air out of the motor and the door closed so I'm sure the motor is good.
I'm trying to trace the vacuum line back to the blend door motor to make it operate properly. Starting at the battery box and the small canisters attached to it, I have 19 lbs of vacuum. There are 2 small valves on the firewall near the battery box. They have two (2 each) vacuum lines going into them and each valve has an electric plug on it. I tested the voltage and 3 of the 4 wires have 13.8 volts while on had only 1.3 volts. Is this right or do I have a problem with on of these valves or is this voltage correct, meaning I still have a vacuum leak somewhere.
Once I get an answer to this I can move on to the next phase.
My problem is a lack of vacuum going to the blend door motor. I put a hose on it and drew air out of the motor and the door closed so I'm sure the motor is good.
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
The temperature blend door motor is electric, not vacuum operated. Please accurately identify which vaccum motor your concern is with.
Those are your 4X4 front axle solenoids on the firewall. Your voltage readings are normal. One of them is always energized so that one side of the actuator on the front differential always has vacuum.
Those are your 4X4 front axle solenoids on the firewall. Your voltage readings are normal. One of them is always energized so that one side of the actuator on the front differential always has vacuum.
Freshman User
Joined: Aug 2003
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From: New Jersey
Thanks. My issue is air blows thru the defroster and not the floor. I've been told the problem is a vacuum leak that operates the blend door. On the drivers side, up between the dash and floor is what looks like a diaphragm with a vacuum hose on the bottom. That hose goes to a harness of 6 hoses. If I disconnect the hose from the diaphragm and draw air out of the diaphragm, the door closes and air come out the floor. I must have a leak somewhere but it's hard to find. Got advise from several members but I don't quite understand.
1997 F150 4.6L 154K miles
1997 F150 4.6L 154K miles
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as SHO89 said there are two systems. There is a motor operated blend door above the transmission hump and under the radio. The variable position damper door adjusts the air temp in the truck........ The other system is "where does the air go".. There are 3-4 different vacuum cylinders that move doors inside the duct to direct the air to the defrost, dash vents, floor, and fresh outside air inlet. There are two controls on the dash. One is TEMPO, the other is LOCATION. WHen you loose vacuum, the doors all spring open and the air goes to the defrost. You can loose vacuum by having a pin hole or crack in the hoses or TEE fittings on the firewall infront of the glove box, or you can have a leak inside the selector **** "valve" on the dash. There are 4 O-rings that seal the ports between the selected locations and vacuum can be lost inside this valve.
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Hotshot
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