Dear Uncle Bill,
Kim and I recently flew from Washington DC to Milwaukee to purchase a
'72 Mark IV, 24,000 original miles, all white with tobacco accents,
We drove it home, or almost home to Mt. Lake Park, MD. The car ran
flawlessly until 60 miles or so the other side of Wheeling, WV (130
miles from home). I had run the car until the tank was almost empty
(recall the car had been running perfectly the first 700 or 800 miles)
and stopped and filled up with gas (high test, Amoco). After about 10
miles the car developed a "chugging and surging" feel. I immediately
thought, "clogged fuel filter".... had another one in the glove
compartment, found a shady spot (I had the necessary tools with me....
old cars and all) and changed the fuel filter... while under the hood, I
noticed that the vacuum advance was unhooked, which explained the
higher than normal idle, and a cracked vacuum cap on a manifold port.
Feeling delighted I had made such discoveries and was able to correct
them; we set off, again, for home. The car ran okay for a few miles,
and then it started chugging and surging again. I thought it must be the
fuel filter again and that I had stirred up so much junk in the tank.
So it went... I stopped 3 times for fuel filters, and each time the car
seemed to run fine for a short period and I was totally convinced it
was all fuel delivery issues. By the time we made it to Wheeling, we
had become familiar with several small towns' NAPA auto parts stores.
In Wheeling, I had decided to put an in line filter on the gas feed
line, and THEN hook it up to the regular fuel filter. Now the car would
hardly run and I began the search, on foot, to find someone to flatbed
it to Mt. Lake Park. It was a Thursday afternoon, 102 degrees and I
could only find someone who would do it for about $500. This, of
course, bothered me and I walked back to the car where Kim had been
reading and being the finest sport about the whole thing.... she told
me she had started the car, and it had been idling fine for about 10
minutes.... I said; "let's go!" and on the interstate we went (we enjoy
and had been traveling secondary roads the entire trip with the
exception of Milwaukee to Chicago).
We traveled about 5 miles, and then the car began coughing, backfiring and
soon there-after, quit all together. The highway patrol came (WV
highway patrol are the best!) and recommended a towing company. They
came, towed us to a Lincoln-Mercury dealer that happened to be at the
next exit and we thought; "our troubles are over"..... Nope, they had a
mechanic out with heat stroke, another out sick, and a stack of work
orders and could possibly look at our car middle of next week.
The towing company, a delightful, family owned (back to the 1930's)
came to the rescue. The driver, who was a grandson of the founder,
said he couldn't tow us all the way to Mt. Lake Park with the truck the
car was currently hooked to. So back to their shop, put the car on a
Flatbed and off we went. Kim on the back seat, reading (it was a brand
new International that was very nice), me up front with the driver, and
being glad we were finally going to be home.
We made it to Shaffer Ford in Oakland, MD in about 3 hours and life was
good again ($450. poorer, but good). Shaffer Ford looked and looked
(based on my fuel delivery diagnosis) then went on their own and
discovered the points were burned, the coil shot and the vacuum advance
totally non-functional. And, there was absolutely no problem with the
Finally to my question: Could my hooking up the vacuum advance (which
was, and is not functioning properly) have caused the points to burn
and ruin the coil? The car ran perfectly (without the vacuum advance
being hooked up at all) before I "fixed" the vacuum leaks. It is my
opinion that the prior owner (now deceased) was aware the vacuum
advance was bad because it was unhooked. The car runs horribly with it
hooked up, so unhooked it is.
Next problem. A vacuum advance is made for every year on record, but
not 1972. Is my only option to replace the entire distributor (the
rebuilt comes with a new advance)??
Also, where can I find out where all the vacuum hoses go? There are
(3) ports on the thermostat housing, and two others on another valve or
sensor to the left (facing the engine) of the thermostat. Can you tell
me? Is there a diagram available?
This car is so nice and original, I would very much like for it to be
the way it was built, and would like to have all that ugly, but
correct, plumbing back in place.
Also, the receipts that came with the car indicate that the blower was
replaced about 2,000 miles and 20 years ago, as was the heater core.
Now, the heater core is leaking (again) and the blower does not work.
Seems strangely coincidental that they are both not working again.
What are your thoughts? How hard is it to change a heater core on a 72
Mark? What's the best way to check the blower?
Bill, thank you so much for being available to ask all these questions!
All the best and hope to see you soon,
Your favorite nephew,
I sure would enjoy seeing some pics of your cars, the 70 Sedan in
That was quite a ride home for you both. It does sound like it will soon be a real nice car for you. It's a good thing though that Kim was such a sport. I hope that the book she was reading was entitled "How I learned To Understand A Car Buff And The Ways To Convert Him Over To Basket Weaving".
A 1972 Mark with 24000 miles is a real nice find but it also has 38 years of aging as you are already aware of. For all we know these 38 years could be 38 years of short drives and low or no real regular maintenance. The problems that you describe appear to stem from not one but several items that may need your immediate attention. I can tell you that the ignition points did not burn from an inoperative or disconnected vacuum advance in fact they may just be the original factory points. This has happened before to very low mileage vehicles so therefore I believe that a complete tune up is in order at this time and that tune up will include an inspection of the interior of the fuel tank and possibly a carburetor overhaul.
The Blower Motor along with the rest of the Automatic Climate Control system is a fine but complicated system. The blower is located under the dash forward of the glove box and you can check there to see if the blower is receiving power. If there is no power there for the blower with the system switched on you then must trace the electrical circuit. I have repaired many of these systems and to this day I always have the correct manuals at my side. To attempt otherwise is not a good idea.
So Carter the above is based on the present possibilities as they appear to me and the fact that you may not know the cars maintenance history. Get a proper set of manuals and if you need further specific vacuum diagrams etc, we can print these off for you. A set of manuals will pay off in dollars and time saved and if you have a mechanic, he or she will love you for having them available for use. I hope that the above will get you started on a smoother running Mark IV.