1978 Mercury Grand Marquis Restoration Journal

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Nov. 2004: The Grand Marquis is currently being restored. When I first got it, it was very hard to start. I replaced the spark plugs and one plug wire, and corrected a loose vacuum line to the PCV valve. The oil and filter was changed, and I installed new transmission oil cooler hoses. (It has an aftermarket transmission cooler).The oil pressure also appears to be low after it heats up...unfortunately this car only has a "Check Engine" light which lights up either for low oil pressure or high temperature! There are no gauges or seperate warning lights.

The vinyl top was totally cracked and disintegrated from the strong West Texas heat and sun. I was able to scrape off the vinyl and re-paint the top in a similar color.

Dec. 2004: The old tires were really worn out...so, I supported the car up on jackstands and removed all 4 wheels, took the wheels in my other Grand Marquis to Discount Tire and had 4 new tires mounted. I did not want to risk a blowout driving again on the old tires.

On Jan. 11 2005 I drove it to Midland, about 25 miles away, to get its state inspection and a brake and alignment check at Midland Frame and Wheel. It made the trip O.K., but the Engine light would slightly flicker when I would stop at lights after I got into town. When I got to the shop, I had trouble getting it re-started.

Jan.12, 2005: the shop called and said the Marquis had a large water leak...the heat of the trip may have caused it. (This was only its second fairly long trip since I got it...the first was when I drove it home. Its last registration was for 1999 before I bought it, so it really had not been driven much in the past 5 years). Hopefully it is just in a hose. I did check the antifreeze before leaving for Midland and the level was O.K.

Jan. 13, 2005: Midland Frame and Wheel finished the work on the Marquis. Front end was aligned, all wheel bearings replaced, rear brake pads replaced, drums turned, wheel cylinders repaired, new air intake hose added to air cleaner. It started up fine so I topped off the antifreeze and drove it down the street to Wall St. Automotive to have them check the other problems including the coolant leak, low oil pressure, hard starting, and check the air conditioning (compressor runs and pipes leading from compressor get cold but there is no cooling in the car.)

Jan. 14, 2005: Wall Street Automotive did a cooling system pressure test and found that the problem was just a bad heater hose. I intend to replace all the rest of the hoses as they look pretty old. I wanted to make sure the problem was not serious, such as a cracked intake manifold or head. Oil pressure was found to be 10 psi hot, 65 psi cold. It appears to be getting higher when hot as the light does not come on as often at idle. More sludge may be getting cleaned from the system.

The car still needed its inspection renewed...the only item left to be repaired to bring it up to code was the left rear taillight which was broken when it was at the car lot. I had attached a taillight lens salvaged from a Ford pickup but that was not up to standards...so, I bought a truck/trailer taillight/turn signal lamp. OEM taillight lenses for this car appear to be nearly impossible to find. I cut masonite to cover the broken taillight and painted the masonite gold to match the car. Then I attached the new lamp unit to the masonite and connected the wires. The modification passed the inspection. It's always so satisfying to get that inspection sticker on vehicles that had been unused for years or were headed for the junkyard...it means they are on the road again.

Jan. 24, 2005: I replaced all of the radiator and heater hoses on the car. This was not too difficult compared to the 80's and 90's Grand Marquis as the 70's models have a lot of space in the engine compartment and a minimum of obstructing engine accesories (such as the upper intake manifold on the late 80's fuel injected 302 engines). Also, I replaced the rubber fuel lines to the carb and fuel pump. The PCV valve was replaced and I found the PCV hose had been connected to a plugged port on the old valve, disabling the PCV system. It is important that the PCV system be functional, because if it is not, crankcase pressure will build up due to blow-by and cause oil to leak out of engine seals. There is a good strong vacuum at the new valve.

I drove the car to the grocery store and the engine performed great...good power, no indication of low oil pressure, no antifreeze leakage. Only problem was that the dashboard lights went out on the way home! I had to click on the interior lights to check the speedometer. The radio and air conditioning control lights worked, though. Will need to open up the dashboard to check those lamps...pretty much every time I have to drive somewhere, night driving is involved, so these lamps are important.

Jan. 26, 2005: I worked on the dashboard lamps today...I removed the dashboard trim piece, it was not too difficult, and removed the screws holding in the instrument cluster. However, the instrument cluster would not pull out. The plastic on the mounting bracket was very brittle. I then removed the trim piece under the steering wheel, and found that the dashboard lamps are actually accessed from behind, and removing the instrument cluster is not necessary. I replaced the instrument cluster screws and trim piece, and checked the dashboard bulbs: bulbs were good. Later, when dark, I checked the cable plugging into the dashboard circuit board...no change in lamps. However slightly moving the bulb sockets themselves (there are two) resulted in success! There was just a poor connection from the lamp sockets to the flexible circuit board.

When starting the Marquis from a cold start today, I got no action. However, pouring a little gas or starter fluid spray in the carb resulted in it starting right up. I decided to check the accelerator pump (which sprays extra gas in the carb throat to keep the air-fuel mixture from leaning out too much when the throttle is opened quickly, and helps prime the engine with fuel for starting) and found that although it worked when its own activating lever was pushed, it was not responding when the throttle lever was pushed forward. This accelerator pump operates differently from the Holley carbs I am used to: on this Motorcraft carb, when the throttle is opened up, spring tension is released on the accelerator pump actuator arm, causing the pump piston to push in. The spring mechanism was gummed up, resulting in no accelerator pump operation when the accelerator pedal was pushed. Will use some penetrating oil on this mechanism to help free it up. Also saw that the kickdown lever was disconnected from the transmission to the carb...the car seems to drive normally, so I may take this to a transmission expert to see if there was a reason why the kickdown lever was diconnected.

Jan. 27, 2005: I sprayed the carburetor accelerator pump linkage and spring with Gumout to help free them up, and saw that the kick-down lever was only disconnected at the transmission end. I reconnected it and it seemed to work properly....pressing the accelerator all the way made the car shift to a lower gear. It appears that there is an E-clip or some such device that had just come off to secure the kick-down linkage to the transmission.

Jan. 28, 2005: I felt that the car was now ready for the real test...starting up in the cold wet fog at 5:30 AM to go to work at the radio station. After a few cranks and pumping the accelerator pedal, it started up and idled smoothly. Acceleration was good through the trip, no indication of low oil pressure when stopping at a light. The dashboard lights worked...however one of them was flickering. Will try some Deoxit DN5 on the bulb socket and circuit board to help clean off any oxidation. The heater performance was excellent, much better and stronger than my '90 Marquis. Windshield wipers worked good, too. After driving the '78, my '90 Marquis feels somewhat like an economy car! The 400 engine seems to have a lot more power than the 302, and the ride on the '78 is much smoother. The '90 and '78 share some features including a similar dashboard style and an illuminated entry system where you can pull up on the door handle and have the interior lights come on for a short time so you can see in the car when getting in in the dark. The '78 does not have the Autolamp or Twilight Sentinel feature that the '90 does.

Feb. 3, 2005: I found some E-clips at ACE hardware and attached the E-clip to the kick-down linkage...operation appears to be good. I had to support the car on jack stands and get under it to attatch the E-clip.Have driven the car to the Retro Lab several times and lubricated the accelerator pump linkage with LPS-2 penetrating oil and this has improved the operation. The oil pressure light has not come on at all so there is more sludge being cleaned from the engine. I do not recommend using any cleaning agent in the oil as this can break the sludge loose too quickly and cause more problems. Just changing the oil frequently when the vehicle is first restored to service has cured the problem in vehicles I own which had low oil pressure.There is a problem with the starter being difficult to operate if you try to start the car when the engine is still hot...a new starter is in order for the near future.

Feb. 15, 2005: Last Monday I changed the oil in the Grand Marquis and used a store brand motor oil...used this same brand in the Dodge van. The oil pressure lights were coming on in both vehicles at hot idle with this new oil, and in the Dodge, which has an oil pressure gauge, the cold pressure was lower too. Today I changed the oil and filters in both vehicles and used Castrol 20w-50 oil to refill...the cold pressure in the Dodge is back up to its usual level and the oil light is not coming on in the Grand Marquis now...will need to do a more extensive test but it seems like the Castrol has made an improvement. I recommend you always use the best quality oil in old vehicles like this that have lower oil pressure...cheap oil has more of a tendency to thin out when the engine gets hot, and there is not the reserve of extra oil pressure at idle that a lower mileage engine would have to compensate for cheap oil viscosity breakdown.

Feb. 21, 2005. We have figured out that the Grand Marquis probably has about 241,000 miles on it! The Castrol 20w-50 is working GREAT in the Marquis and the Dodge Van: oil pressure is better at start-up and when cold and still holds up when the engines get hot. Have noticed a gasoline-like odor when starting up the vehicle but cannot see any really obvious leaks. Before I drive the Marquis again I am going to go ahead and install a new rebuilt carburetor, fuel pump, and starter. Have been having trouble getting it started and stalled out at a stop sign when the engine is cold...performance good when engine is warm, though. Calculated miles per gallon at 13 for mostly highway driving...not bad for the 400 engine (the Dodge 360 in the van gets about 10 MPG)...with a new carb, mileage should be even better.

Mar. 24, 2005: I installed a new fuel pump yesterday on the Marquis. I discovered that the gasoline odor was caused by gasoline leaking out the top of the fuel pump, and had not driven the car till I fixed the problem yesterday. The new pump led to much better engine performance.

Mar. 25, 2005: This morning when I drove the Marquis to work, the ALTernator warning light stayed on when I shut off the key. I pulled the negative battery lead off the battery to keep the battery from discharging while I was on the air. When I reconnected the battery, I heard the voltage regulator click, leading me to believe the points inside were stuck. Drove directly to Autozone and picked up a solid state replacement regulator for 9.99. This solved the problem. Also picked up a new starter to help solve the problem of the starter drive sometimes not engaging. Oil pressure continues to be good even after driving for a long period.

June 8, 2005: Have been having mostly trouble-free operation of the Marquis...noticed a few troubles ocurring this week though. This weekend I turned on the air conditioner and let it run for a while to see if by luck it might just start working...however I noticed a burning smell like burning rubber so I shut it off. When I got home I found the magnetic clutch was smoking when engaged and there were ball bearings rolling around loose. Not sure if the trouble is just in the clutch or if the compressor seized up...I disconnected the belt from the compressor and the power to the clutch to prevent trouble (the belt for the air conditioner compressor luckily does not power anything else).

Then, I noticed noise while turning the steering wheel...opened the hood and heard a whining sound that got worse as the steering wheel was turned...looks like a new power steering pump will be needed. The car will be out of commission till I can replace it.

I saw a 1976 Marquis that appeared to have last been driven in 1985 at a garage sale...they wanted $400 for it. I will likely pass on it as someone threw a rock through the windshield and totally shattered it, there is leaves, dirt and tree branches blown inside through the non-existent windshield. The hood was also messed up and I couldn't get it open. It's a shame to see it vandalized like that as the body is in good shape.

July 26, 2005: I checked out the power steering system and found that the power steering reservoir was low...filled it up and good performance was restored. It appeared though that fluid was slowly leaking from the steering shaft on the gearbox...I will try some power steering stop leak but if that doesn't do it, a new steering gearbox may be needed.

August 15, 2005: I added Prestone power steering stop leak and this has improved the steering fluid leakage but not eliminated it, so I'm planning on installing a new gearbox. Had a breakdown of the Marquis at the local grocery store...the only time it has ever left me stranded. Battery had died and couldn't get it re-started. Gregory's car was in the shop and none of the keys to the other vehicles were at home, so he could not come and get me, so I had to walk about a mile home and get the battery off the tractor to get the Marquis re-started. We drove it out to the Marquis in the Dodge van and I was now able to get it to crank but it wouldn't fire. Finally after holding in the gas pedal all the way I was able to cure the flooding and it started but now I was getting tappet noise! What a string of bad luck.

Drove it home and took off the valve cover where the noise was coming from (driver's side). I tied the spark plug wires out of the way and started it up with the valve cover off, and sprayed PB blaster penetrating oil into the valve train components. This quieted down the noise, so it appears something in the rocker arms or pushrods had been starved for oil or was stuck, though there appeared to be a good flow of oil onto the rocker arms. I cleaned off the valve cover and will re-install with new gasket.

I measured the battery voltage on the good battery while the engine was running and it was 12.8...appeared the alternator was not working. I took it off and took it to Autozone where they confirmed it was bad. Will install new alternator and belt.

August 19, 2005: I installed the new alternator. Voltage at idle is ablout 13.7 volts so it appears to be working O.K. I got a neoprene Fel-Pro valve cover gasket set and replaced the driver's side valve cover gasket. Drove the car to work and it is running very well...the tappet noise appears to have gone away.