Hi Bill –
We just bought a 1972 Lincoln Continental, all original. In great condition!! Couple little fixes and one of them is that the headlamps stay open when you turn off the car and the AC seems to blow cold, but then shuts off and then spurts cold air again.
The mechanic I took it to says we need to replace the valve fast idle cam (someone else called it a vacuum manifold?) its a 9 port and he says it controls the entire vacuum system.
I have read some of your older posts and wanted your opinion, we’re having trouble finding the part. May have located an original.
Are we in the right direction on the repair, or any other suggestions? and any recommendations on where to get this part, or its part number?
Mammoth Lakes, CA
Hello Donna –
Nice car to have! They look great and command plenty of attention. These two issues that you describe are not related and my opinions will be based of course only on the information that you have provided.
If your mechanic has diagnosed the vacuum headlamp cover issue correctly he is referring to the vacuum distributor that is located on the firewall on the engine side. It contains a vacuum valve that functions to lock vacuum in the Headlamp Cover vacuum circuit when the engine is off or at times of low engine vacuum. This valve can fail. We should have that item in stock in good used condition. Be aware however that any vacuum routing in the circuit also may be at fault and there could be more than one leak.
Your description “the AC seems to blow cold then shuts off and then spurts cold again” sounds like one of the two relays on the engine side of the firewall or its connection has failed. The High Blower Relay will operate the blower at high speed until the A T C begins to moderate to a point that the relay will hand over the High blower speed to the automatic lower blower speeds. It is at that point that these relays are well known to fail internally. We will have these in stock or we offer a service to test and rebuild your relays.
Again, the above is based only on your information as well as what we encounter here at Lincoln Land on a daily basis. Further diagnosis may be necessary. If we can help you further with any of the parts or services as described above or if you may require any Shop Manuals for your 72 Lincoln please do not hesitate to contact us again at any time. We do hope that the above helps you with your repairs.