I have a vacuum leak in my 2003 Powerstroke 6.0 that I've been trying to trace, the vacuum pump runs constantly. So far I have replaced hub seals, o-rings, locking hubs, vacuum lines to hubs, 4x4 solenoid, and vacuum pump. Both hubs, and the reservoir hold vacuum with a handheld vacuum pump and all the lines have been replaced and test ok. While tracing all vacuum hoses from the reservoir I noticed hissing and felt air coming from around the line going into the air conditioning evaporator (see pictures); would that be part of the vacuum system? I've noticed in pictures on the internet that there is some type of putty or seal around that line, but I wouldn't think that missing couldn't be causing the leak. I have tested everything else and running out of things to look for. Any advice is greatly appreciated...
badman2860
That's an a/c line, not vacuum.
A leak in the 4x4 system would only operate the pump if 4wd is selected. Since the solenoid keeps it segregated (unless the solenoid is faulty).
With the key on, disconnect the vac line heading to the firewall. It's seen in the first pic, clipped to the cowl bracket. It looks like it's been messed with as those connections aren't factory.
Disconnect it as close to the reservoir as it goes by itself. Then plug the reservoir end with your finger. Wait a minute. Does the pump stop?
A leak in the 4x4 system would only operate the pump if 4wd is selected. Since the solenoid keeps it segregated (unless the solenoid is faulty).
With the key on, disconnect the vac line heading to the firewall. It's seen in the first pic, clipped to the cowl bracket. It looks like it's been messed with as those connections aren't factory.
Disconnect it as close to the reservoir as it goes by itself. Then plug the reservoir end with your finger. Wait a minute. Does the pump stop?
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