A Grand Marquis far from home - Life with my 1988 Mercury Grand Marquis GS

[Arquemann]

Shipping for the brake rotors is gonna get ya! Also a brake rotor is about the only cheap chinese part I'd dare to buy, being a single chunk of iron. Still I went with reputable Raybestos when I did the front brakes on mine. Atleast get reputable brand brake pads.

Did someone fiddle with the headlight switch? Both auto lamp and courtesy light problems could be from the switch. Atleast make sure no one accidentally left the auto lamp off...

The fuel gauges / senders can be a bit wonky. Don't read it like in a modern car, it's more suggestive than accurate information. When the fuel light comes on sometimes I fill 55 liters, sometimes 65 liters... Also my gauge shows about 5/4 full when actually full.

And your sig still has a Vic in it

[kishy]

• The auto lamp function suddenly does not work, but worked when I left the car. It has gotten a new battery since but that shouldn't be affecting it. I remember seeing the light sensor on RockAuto in the past, but now I can't find it. After some googling, I find a part called "Sentinel sensor" - is that the part on the dash that senses how bright or dark it is outside?

"Twilight Sentinel" is the name GM used for the same functionality as "AutoLamp" - this is akin to calling all tires Pirellis instead of the word "tires"; it's like a brand name or trademark.

I am not aware of anyone manufacturing or selling new autolamp sensors, nor that any have been available for a long time. The sensors do fail, in both "on" and "off" modes, so it may be at fault. Someone on this continent could find you a used one and sell it to you, hopefully tested as well. But, this may have some relation to the next item, potentially.

• The interior courtesy lights work, but also kind of don't. Opening the drivers door sometimes turns them on, sometimes does not. Turning the dimmer switch now in the garage did not turn them on, but I did notice that the courtesy lights turned on when I lifted the door handle to check that I had locked the door. Any theories as to what might be afoot here?

The "illuminated entry" feature (lift handle to turn lights on) uses a module containing a relay and a timer circuit in the dashboard. This is separate circuitry bypassing the physical switches to get voltage into the bulbs. It does not surprise me that it, and your various switches, are at odds with each other.

The buttons in the door jambs which turn on / hold on the lights when a door is open can become sticky/gummy and not fully extend when the door is open, thus causing them to not turn on the lights.

The part of the headlamp switch which turns on the lights is quite fragile and prone to breaking. Visual inspection of the headlight switch would be wise but this is a little challenging on the 79-89 Ford or Mercury dashboards...my initial suspicion is that the ceramic disc which is part of the instrument dimming function (and also for turning on the courtesy lights manually) is broken and contact isn't being made anymore.

Also be warned that the wiring into the headlight switch is a known point of failure due to overheating and then melting the connectors. I don't think your symptoms necessarily indicate this is happening but it's worth inspecting to get ahead of it, in case it is.

• I'm wondering if the fuel gauge is funky. When I picked it up the fuel lamp was on, which turns on when there's like 10% of fuel left right? It's my understanding that these have 18,5 gallon tanks, which should mean that it would've had like 1,85 gallons left. But as much as I tried at the gas station I could only get 14 gallons into it - a discrepancy of 2,35 gallons. What might this be? The sender unit in the tank packing it up?

I would consider that to be likely be working "about right".
The light turns on when the value of the sender reflects the same value that the gauge is supposed to report as 1/8.
It is not particularly precise and shouldn't be thought of as such.

I generally fuel up my vehicles before they get under 1/4 for a number of reasons, none necessarily concrete enough on its own, but as a collection they make sense to me.

• what if I wake up tomorrow and want to drive a great distance without having time to stop for gas?
• what if the price of fuel at the nearest convenient station is undesirable but I don't believe I have enough range to get somewhere cheaper?
• what if the fuel gauge sender has become less accurate since the last time I ran the tank very low and the amount it indicates is no longer trustworthy?
• prevailing opinions that the cooling effect of a pump being submerged within fuel extends its lifespan/buys extra time out of an old tired pump that will fail if stressed by excess heat

and another one worth considering if the car doesn't see a lot of mileage and/or the air where you live is naturally very humid:

• the inside of a fuel tank can rust quite aggressively if full of moist air rather than fuel and while tanks are available, life's just easier if the original can remain in use longer.

Also bear in mind the fuel tanks in these vehicles lack any type of baffling or reservoir feature like some other vehicles have. As a result, a lower effective remaining level of usable fuel equals a larger amount of actual fuel in the tank than you may be expecting, as some of the fuel is inherently not accessible because it's spread across the whole bottom surface of the tank rather than being funnelled into a low spot where the pump can get it. I could certainly imagine that around a gallon of fuel remaining might be well into the "danger zone" for the pump no longer being able to get a consistent supply of fuel when accounting for cornering, inclines, etc.

...
measured the discs and they're warped from the calipers being tired. Discs for $14 from RockAuto! Not to mention the calipers that were practically free as well. I know I sound like a broken record but I can't get over how cheap the parts are. Still it feels great finally having the car back, to finally actually get to drive it! Celebrating with a commute to work tomorrow.

Do keep in mind that many of us have identified that the stock brake design on these cars, for reasons that I don't think anyone has fully explored, seem very prone to warping. I would guess the ineffective-as-it-ages slide pin design has something to do with it.

Despite the low cost of replacement brake parts I am an advocate for getting them machined ("turned") anyway. The original parts (if indeed it still has them) will have been made of a better grade of cast iron (or whatever it is) than what new stuff is, and will likely have been cast, drilled, and machined more accurately. I would not discard the old rotors unless they are too thin to be worth saving for future reuse, or if you can't find markings to suggest they may be Ford original parts.

[Arquemann]

Despite the low cost of replacement brake parts I am an advocate for getting them machined ("turned") anyway. The original parts (if indeed it still has them) will have been made of a better grade of cast iron (or whatever it is) than what new stuff is, and will likely have been cast, drilled, and machined more accurately. I would not discard the old rotors unless they are too thin to be worth saving for future reuse, or if you can't find markings to suggest they may be Ford original parts.

I'd guess mr. Tynnerström is in the same boat as me; brake rotor machining being pretty much non-existent. Atleast in Finland, a machine shop is basically the only place to get rotors machined. And that also costs machine shop prices.

[DerekTheGreat]

DerekTheGreat that makes two of us! That was the car I drove during my university years, but since then my dad has sort of inherited the car. It only has 99k miles and runs super great still.

It is to my great relief that I announce the car is back in my hands! You'll recall that I sold the Roadmaster almost a month ago to the day, and what a long month it was being without a car....

...I'm wondering if the fuel gauge is funky. When I picked it up the fuel lamp was on, which turns on when there's like 10% of fuel left right? It's my understanding that these have 18,5 gallon tanks, which should mean that it would've had like 1,85 gallons left. But as much as I tried at the gas station I could only get 14 gallons into it - a discrepancy of 2,35 gallons. What might this be? The sender unit in the tank packing it up?

As soon as we get temperatures above freezing again I'm doing the front brakes and wheel bearings. There's a vibration when braking but since I didn't feel it in the steering wheel I thought the drums were bad, but my guy measured the discs and they're warped from the calipers being tired. Discs for $14 from RockAuto! Not to mention the calipers that were practically free as well. I know I sound like a broken record but I can't get over how cheap the parts are. Still it feels great finally having the car back, to finally actually get to drive it! Celebrating with a commute to work tomorrow.

That T-Bird, is it a 5.0, 3.8 or 4.6? I just now noticed the Clinton/Gore sticker. I remember that election. My eldest brother is an astounding artist, even back then. He drew a caricature of Gore in which his facial features sort of resembled an oven fresh pizza held sideways, with all of it's toppings sagging along with a caption that read, "Don't vote for Gore, he's falling apart!" He'd press that drawing against the window of the family hauler as we drove past people. Surprised I still remember that, I was only six in '92.

If the low fuel light comes on within the 1/4 tank area, I'd say it's working correctly. As others have stated, it's not accurate and serves to grab your attention on long drives so you don't wind up out of gas.

I also appreciate how cheap parts are for these, wonder how long it will last. The quality sucks, but so does the quality of the more expensive parts we have to buy for my wife's 2002 Tahoe. If those rotors are original, I'd look at getting them turned as well. If the bearings & races are in good shape, I'd clean & repack 'em.

[Tynnerstroem]

Gentlemen thanks very much for your input! Great writeup kishy! It also makes sense now what you say about them failing both on and off, since they were always on before.
I have noticed that sometimes (but not always) if I have the lights on, but no key in the ignition and the doors closed the chime will go off, which seems odd as well. So something's up with the interior lights for sure.

Being on daily driver duty this time of the year sure bathes it in salt. I managed to time coming back from my folks yesterday with the salt trucks being out and about, which you can kind of tell. So off to the automatic car wash! I realize those are blasphemous among car people, but this car isn't mint so I feel no shame about using one.


It went kind of well? I noticed some water coming through by the A-pillar, which doesn't worry me all that much. The windshield has an inspection sticker from Georgia issued in 1999, so who knows how long ago it was glued into place. This feels like it will resolve itself when I get a new windshield, which the insurance company will pay for when I get a crack in it (which you always get in the winter anyways).


I did hear a noise like trim coming off as well. Took a lap around the car in the dark when it was finished and didn't see anything, so I figured it was just the trim around the vinyl top that creaked from the brushes. I have noticed it not being super firm in place. Took another look in my better-lit garage, and this piece had fallen off.


Now luckily it was right there in the car wash so I picked it up. These clips or whatever one might call them look really tired, so I'm surprised the other side stayed on.


The good part is that there's no visible rust under where the trim piece goes, and the car cleans up pretty well. But the clips here (and honestly probably on the other side and around the rear window as well) will need fixing. Can these still be bought and switched out? Or at least some clips that are similar enough? Or will one have to do some kind of glue-type patch up to get the trim back in place?

[Mainemantom]

You should be able to get the stainless piece and the clips together when buying used. Try to get this replaced right away. You don't want the wind to get under the vinyl top and start pulling it up or to get water/salt under there. I have found with my 90 CV that those clips are a pain to access from inside the trunk and the C pillar area. Mine has little nuts in back of the clips holding it tight.

[Tynnerstroem]

Thanks Mainemantom! Do these appear to be the correct ones? If so I’ll order them right away.

https://www.ebay.com/itm/122108819853?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=x-y2-q2QQ8-&sssrc=4429486&ssuid=AMDpsDc8QNC&var=&widget_ver=artemis&media=COPY

Do the same types of clips hold the trim around the rear window as well? I am also a little worried about the trim around the front window, are you aware if those clips are similar or different? Ideally a glass place would switch those out when they do the front window.

[Arquemann]

Those clips are wrong for the pillar trim. Not right for the window mouldings either.
The pillar trim clips twist into the trim piece and the spring holds them in, then they're fastened with nuts from the backside.
Probably could be reused unless the springs are broken.

These look more correct, don't ya think?



https://www.ebay.com/itm/204942636357?fits=Make%3AFord&_skw=ford+moulding+c lips&itmmeta=01JFA1V3TBFPKQRTNEEZBV1WEH&hash=item2 fb7887545:g:06QAAOSw8wJmvgwU&itmprp=enc%3AAQAJAAAA 0HoV3kP08IDx%2BKZ9MfhVJKlRVH9lRxI19shegNUa7IpgBRGv PfeZJ%2BlHnC3%2FQ8byj%2FPt2thv2OGNiJq9Cc1s4LSq1SC7 K2e43qbN7dYINDFKY0HdjFMfFranWw1uH2k7rsgdlS6hHkVrpu fxoJhNXX7zOrvbbsaGcB5rSASnuCG6OIn5rD8hNWDMdd9v3hM6 J7guK7RZs8d5zb0kRxSKH%2FAEGNz107ELa5B6rJqm450ZUGnT LZsTK5sfQTA3AllO26vp%2FVMckyyY1yVpAh5bXEA%3D%7Ctkp %3ABk9SR6a97MH6ZA

I wouldn't take her through an automatic wash again, unless it's brushless. Otherwise the next time it'll be the hood ornament that'll fly into oblivion and break in a way that can't be properly fixed.

Front and rear window trim has rectangular springy clips, I don't know what fits. Also dunno if they're different front to back.



Except for the bottom of the rear window trim, which uses these:

https://lmr.com/item/HDW-42006C/mustang-rear-lower-windshield-molding-clips-79-93-coupe

[Tiggie]

In addition to the above: https://www.amkproducts.com/bulk-fas...oduct_ID=13154
These are the clips for the window trim, but you stand a good chance of being able to reuse your existing clips like this. They are usually buried in sealer and nearly impossible to get out. There are cheaper versions of this clip out there, but they suck. These are perfect. I used them on my 90.

[Mainemantom]

There is a special tool to detach the window trim clips. You have to be very careful using the tool or you will break the glass. My recommendation is to take it to a glass shop.The cost for them to do will be minimal. If they break the glass, they replace it.

[Tynnerstroem]

Thanks as always gentlemen! It does look like them Arquemann, but the ad says those only fit cars up to 1986. Does anyone know if they should be similar for my 1988?

I ran the car through the wash again today and the other side roof trim came off, which was to be expected I guess. That trim piece bent though and might not be reusable, but we shall see. Maybe I should just realize that this car is not perhaps compatible with the use I have intended for it.

[Arquemann]

Thanks as always gentlemen! It does look like them Arquemann, but the ad says those only fit cars up to 1986. Does anyone know if they should be similar for my 1988?

It's ebay, don't be bothered by the vague compatibility lists. I linked the ad based on what I could see in the photos you took of your car...
Pretty sure the C-pillar trim is the same on 88-90 with normal tops and possibly all years with the formal top (frenched rear window).
Pre-88 the trim is a bit different shape and slightly higher, but it attaches the same.

[Tynnerstroem]

Thanks very much! They do look basically the same to my untrained eyes.

I've been driving the car a lot lately, commuting basically every day. The wind noise that I thought excessive now makes sense, since it seems to come from the same spot where water comes through on the A-pillar in the car wash. Once the windshield is swapped out with fresh sealer those two problems are hopefully gone.

My dad got me one of these EEC-IV code readers that's actually for Fords for Christmas (you'll recall some posts back I said I had one, but for GM cars), very considerate of him. I ran KOEO and KOER and it threw four codes at me, none at KOEO though but all of them during KOER. These are:

1. 12
2. 44
3. 74
4. 94

44 and 94 both seem to concern the smog pump not working - not exactly a huge surprise after all these years. Now it's my understanding that this not working isn't exactly a big deal for the functionality of the car right? If so I won't be doing anything about this. 12 and 74 are more interesting. According to a thread elsewhere on this forum, 12 means cannot control RPM during engine running self-test high RPM check, or basically that the engine idles too high according to the book that accompanied the code reader. You may recall that my IAC valve was acting up and after I cleaned it, it seems to work better. However after driving the car and putting it in Park, I have felt that it idles too fast, so I'm thinking I'll try to order an IAC valve, even though most of you said it's hit or miss with the quality of them.

74 seems to concern a brake switch failure, which gives me hope for that being the culprit causing the cruise control not to work. I will order one from RockAuto together with that IAC valve and switch it out, hoping that will sort the cruise control. Is that all that the brake switch does, act as a switch of sorts for the cruise control? I was guessing it had something to do with the brake lights but those work perfectly on the car as-is.

Finally, the car has developed an intermittent belt squeal, for basically half a second when the car starts and sometimes under load, but it always goes away when letting up the pedal. The belt that drives the smog pump and the A/C compressor is one I haven't changed, due to the pulley highlighted in the image below being tired but me not being able to find one, leading me to suspect that belt as I changed the other one.

Or rather, I found one on RockAuto but on the car there's no bolt to switch the pulley from the bracket (it seems to all be one piece), so I never got around to changing the belt. Now this squeal is lending urgency to the task, so I turn to you guys - have you any tips on how to deal with this pulley? Can the entire assembly be found somewhere? Or will I have to go at this problem from some other angle?

Finally, here are three images from life with the car lately. I'm sure this sight will be familiar to most of you Panther-owners these days. No matter what parking spot you find, they are always too short, too narrow and too close to other cars.


I also took it to Costco for some shopping, where I am sure that the car felt right at home. Thankfully the lack of trim pieces for the C-pillar isn't the first thing you notice, but those definitely need to go back on as soon as I get new clips. It's funny how the car is basically a two-face: great looking when clean, and ratty looking when dirty which it mostly is when driving it on the regular during the slushy, salty winter we are having this year.


Shopping at Costco will sure make you appreciate that huge ass trunk.

[Arquemann]

Look up an '88 Colony Park instead on RA, the full tensioner assemblies are available. For some reason they don't show up with all years or engines.
Belt squeal on startup could just be old and/or loose belts. There is no soft-start alternators or ac compressors on these. New belts and making sure they're tight usually works.

[sly]

I had to do that with the 82 Lincoln Mark VI... use 88 MGM for mechanicals. Learned this after having to bring in the old parts off the car to prove to the AZ dolt that the parts lists are WRONG for the Mark VI. It's a panther, not a fox. And yeah... Ford is to blame for that one. 88 seems to be the best list for panthers.