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

[DerekTheGreat]

If my threads didn't go off topic, they wouldn't be my threads.

Valve stem seals.. I suppose a fella with more mechanical aptitude than me (And I don't have much) could do it in their driveway. Something about pulling the spark plug out of each cylinder, feeding said cylinder compressed air (while both valves are closed) to keep the valves from dropping while you use a spring compressor tool to then change the stem seals. Meh, that's a job I'd farm out.

The rough idle was the start of it. But I am surprised it ran ok otherwise. The car I knew would misfire under load, but would cruise and idle ok. Plugs didn't look close to yours in terms of nastiness. Funny how that stuff goes. If I was in your shoes, I'd just be tempted to throw new plugs at it a heat range higher and drive until the problem cropped back up, if it even did.

[Tynnerstroem]

DerekTheGreat these plugs are in now anyways but I'll keep hotter ones in mind if the car starts running roughly again.

I finally got the heater core from RockAuto and will tear into it tomorrow after work. I have the factory shop manual and have found two good videos on YouTube detailing the job so I am not too worried about it. Any things you guys feel I should keep in mind while doing this job?

[kishy]

DerekTheGreat these plugs are in now anyways but I'll keep hotter ones in mind if the car starts running roughly again.

I finally got the heater core from RockAuto and will tear into it tomorrow after work. I have the factory shop manual and have found two good videos on YouTube detailing the job so I am not too worried about it. Any things you guys feel I should keep in mind while doing this job?

The aforementioned hinge issue in the HVAC system. If you're there anyway, it would be wise to assume the hinges will be broken and allow time/other resources to take care of that problem (e.g. a means to get to a hardware store during business hours while the car is apart).

Even if not broken yet it's sort of an inevitability, and with how hard it is to repair, my vote is to take care of it.

[mcb82gt]

As noted, the buildup on the plugs at the rearmost two cylinders results from oil consumption. On an engine with good valve seals but which is still generally worn, those cylinders will consume oil more than the others via the PCV system, and on an engine with bad valve seals (which is probably all of them that have never been done before), it will be amplified. With the engine being tilted rearwards as it is, gravity makes more oil pool towards the rear of the head so the valve seals more likely to leak a larger amount of oil are those ones.
.

Anyone run a catch can on these, wondering if it would help with the oil on #4 and 8?

[DerekTheGreat]

Anyone run a catch can on these, wondering if it would help with the oil on #4 and 8?

Like kishy mentioned, the angle of the engine and the leaking seal are the issues. Oil ends up pooled there and pulled into the cylinder through the valve guide. A catch can would only help with oil vapor.

[kishy]

Anyone run a catch can on these, wondering if it would help with the oil on #4 and 8?

Like kishy mentioned, the angle of the engine and the leaking seal are the issues. Oil ends up pooled there and pulled into the cylinder through the valve guide. A catch can would only help with oil vapor.

So...there's a lot going on here when you think about it.

1. On an engine with not-ideal-condition valve guides and seals, the natural pooling of oil towards the rear of the heads causes the rearmost cylinders to burn oil as it enters the cylinders around the valves. We address this by doing a valve job, basically.
2. On engines which do or do not have the above problem, the rearmost cylinders can still burn oil via the PCV system, because the way the PCV system is plumbed to the intake means the vacuum basically sucks it into the back of the intake manifold. So if a lot of oil vapour gets sucked through the PCV system, it ends up in the intake, and more of it ends up at the back than anywhere else.

To address #2 we can do a few things. Some sort of additional baffle underneath the lower intake manifold would reduce the amount that the PCV system can suck in. It also certainly doesn't help that the PCV is drawing from the rear of the lower intake, where once again, a greater quantity of oil is hanging out in the engine valley. I am not aware if any such baffle is manufactured or sold...most people don't mod their PCV system and instead just neuter it so it's useless.

A catch can would probably work, but I have a feeling that just using a much larger diameter hose for the PCV, and routing it longer/further away/higher up before it comes back down to the vacuum source would do wonders for how much oil it can suck up, whether or not a catch can was installed on that hose. If the hose is longer, there's more distance for the oil to fall out of suspension in the air, and then run back by gravity to the PCV valve rather than making it all the way to the vacuum source.

It's an awkward spot to work on.

[Tynnerstroem]

Heater core job is done! Wasn't exactly fun but at the same time didn't feel like the end of the world like I would see it described elsewhere on the internet. I worked remotely from my dads place and got to work at 5PM on Friday.


You'll note that on page one of this thread, I briefly mentioned that my dad drove a Seville in the 1990s - the withdrawals were seemingly too much so he bought another one, which is a bit of a project. For now though it works great as a desk to keep the shop manual and tools on.




By EOD Friday all that remained was the hoses and the two bolts on the stud next to them on the firewall before the heater core would come out. I decided to remove that awful cloth they had put on the dash to cover up the cracks to see how bad it really was. While the dash doesn't look good, it wasn't as bad as I'd imagined it to be under there. Plenty of glue residue where they had glued that cloth piece on, and they seemingly put foam over the speaker holes for some reason.


After reading the newspaper and having two cups of coffee Saturday morning I got to work on the rest. When pulling on the dash I felt that it wasn't really flexing that much, and being risk-averse by nature I decided to remove even more stuff, including the three screws on top of the dash (that are hidden by the dash pad) to make the dash flex even more. In the videos I'd looked at online it didn't seem like they did that, but I was afraid I'd crack the fragile plastic the dash is made of if I didn't.


And out the heater core came! Nasty it was, both the core itself and the plenum in which it had leaked. Managed to spew some coolant on the carpet as well despite my best efforts, but since the car will get a professional interior detailing soon I figured it was no big deal.

[Tynnerstroem]

Getting the new core into the plenum was a bit of a struggle, with that foam thing that goes around it putting up a fight. I did clean out the plenum before putting the core in there, like I said above it was nasty in there.


Putting it back into the car was honestly pretty uneventful once I managed to rotate it in underneath the dash. I had plans to get it in and test drive it before Saturday was over, but I stumbled on the finish line. I at least got it back into the car, idled it up to operating temperature, aired out the system and made sure there were no visible leaks and that heat actually came through the vents. So far, no issues.




One newspaper and three cups of coffee later on Sunday morning we took it for a test drive - the final exam! Drove it pretty carefully to a parts store (to get some contact cleaner spray for the cruise control servo - didn't fix the cruise not working) but then I floored it on the highway entry ramp to see whether it held or not, just like I floored it when the heater core handed in its resignation two weeks ago. It held tight! No smells or smoke. Checked the fluids and topped up one last time back home.


With the car working properly, I put it all together again. One thing I struggled a bit with is getting the fit of the glove box 100%, which you can kind of tell from this photo. I did put it back the way it was, but maybe there's some adjustment that I missed or something.


Here's what the top of the dash looks like now installed in the car. Call me crazy but still way better than it was before, but a new top will be ordered and installed next spring/summer. I notice that the dash pad is significantly darker than the rest of the dash, but maybe it is supposed to be that way? The dash pad had a Ford OE-number stamped on it so I don't think it's some aftermarket thing.




A parting note - driving these two back to back is really interesting. The Mercury feels so much older. Now granted my Buick has a factory handling package, 115hp more and a 2.93 rear end so it will definitely feel peppier, but also sitting in it feels like sitting in a much more modern car, which I attribute to the huge dash and overall soap bar-shape of the car, compared to the 1970s-square style of the Mercury.


So now I've put the car on daily driver duty with my father for the week, to see if any other faults pop up. If it survives that I'll take it to a Cars & Coffee on Saturday morning, and if all of this is successful I'm putting the Buick on the market. Next steps on the Mercury are:

1. Troubleshooting the cruise control - the only thing I've done is to put contact cleaning spray on the connector of the cruise control servo and checked that there are no LED's in either the brake lights or the third brake lights. I do have the factory shop manual with a step-by-step guide but welcome any input from you guys here.
2. Fixing the window motors in the rear to ensure that there's no leak from them not closing properly. I have the motors so just need to get to it.
3. Troubleshooting the power locks, which everyone says seems to be the actuators. I'll be looking at the one door in the back where it doesn't work when I do the window motor just to confirm, and if so I'll just order four of them from RockAuto. Are they a pain to change out? Any tips and recommendations from you all here?

[DerekTheGreat]

Wow, with a heater core behind you, your patience and abilities surpass mine. Although, I have done and will do them on 1987-1996 Ford F-Series trucks and General Motors GMT400 stuffs. Takes about an hour for those, super easy even for me.

I'm telling you, the Roadmaster is where it's at, I'd be keepin' that. I love my Town Car, but the extra torque, space in the engine compartment, features and being able to connect a scan tool to the Roadmaster make it superior to the Mercury for daily driver status.

Your dad's Seville, is it still sporting the factory fuel injection set-up? I can't remember if that was standard or optional equipment on those. I'm fairly certain it was an option on the Fleetwoods, which is what I'd want to roll around in.

[kishy]

Good work.
I see no mention of the hinges - I take it they were in satisfactory condition that you opted not to mess with them?

I have no experience troubleshooting cruise on the years where cruise is integrated in the engine control unit (87+), but I'm sure your system works the same as my 91 so I may be able to scan some pages in the shop manual if it helps.

Window motors and lock actuators are both moderate pains to change out. Drilling the rivets on the lock actuators is by far the easiest way to get them out. What I've done in a couple cases is then JB weld a bolt into the bracket that goes on the actuator, and presto, serviceable design for the future. The window motors are possible but very challenging to do without drilling out the dimples on the door structure to make access for a socket. The first one I did, I resisted drilling, and then after that I drilled the holes on all the rest.

Pictures would certainly help explain the points I've made here but I don't have them readily handy - can follow up later if you'd benefit.

[Tynnerstroem]

DerekTheGreat I believe it helps that this car isn't yet my only one. If something goes wrong I can shrug, pour myself a glass of wine and simply think "I'll try again next weekend" since I don't depend on it. We'll see how that changes once I'm actually using it. You're not wrong on the merits of the Roadmaster, and I'd love a B-body of this generation but this particular Roadmaster isn't it. As I've explained elsewhere in this thread it's a bit too hacked into for my taste. OBD is a godsend though, but I'll take my chances - if I'm wrong, I can always just sell the Grand Marquis and get something else.

All Seville's came with the fuel-injected Olds 350 (unless it was a diesel), and this one actually still has it! There have been a number of Seville's in the country over the years although they were never officially sold here, but many were converted to carburetors. The service network that was in place here for US cars mainly dealt with Chevrolet trucks, Chevrolet G-series vans, Ford Econolines and the odd Caprice, they basically all had 350's (or 302's) and carbs, so no one was really capable of handling these fuel injected Seville's (or other fuel injected US cars of the era) here, so many were converted to whatever carburetor could be found - same with the diesel Oldsmobiles (that were actually sold here). Many were converted to gas V8's or simply junked.

kishy you're right - I did look at the operation of the hinges. My layman's opinion is that the plenum had never been out of the car (core looked original), but the hinges' operation were satisfactory and showed no obvious signs of being about to fail. My fear was that if I started digging in to them I'd struggle to get it back together in any functioning manner, so I'm taking a bit of a chance on them. Hopefully I'm not proven wrong any time soon.

I have the shop manual for my car, thank you though! I'll dig into both locks and window motors next weekend since this one has filled up with social obligations. The cold season is fast approaching, and while you technically can wrench in a driveway year around, it's preferrable to get this stuff out of the way when the temperature is at least above freezing. I did note on RockAuto that the door lock actuators they had were only listed as "front", none for the rear. Are they the same front and rear though, or is there something else I should know here?

Another report from my dad, who is currently using the car for daily-driver duty (to try and see if any other issues pop up before I start using it) and he told me the wipers weren't returning to their hidden position properly. I haven't had a chance to look in person yet but if that is actually the case, does that signal that the car needs a new wiper motor? I note that there are none in stock on RockAuto, which worries me but maybe it could be something else?

[kishy]

Same actuators front and rear, however the actuators are semi-universal in that they come with a variety of pushrods to select from. The back doors use a pushrod that the new actuators don't include, so you need to do a little part-swapping from the old to the new.

Off the top of my head I believe the wipers failing to "park" is more commonly a fault with the switch, but I may very well be mistaken as I've never troubleshot the problem. When any of mine have failed to park I just cycle the switch a couple times and they seem to figure it out and pull down where they belong.

[DerekTheGreat]

DerekTheGreat ...You're not wrong on the merits of the Roadmaster, and I'd love a B-body of this generation but this particular Roadmaster isn't it. As I've explained elsewhere in this thread it's a bit too hacked into for my taste. OBD is a godsend though, but I'll take my chances - if I'm wrong, I can always just sell the Grand Marquis and get something else.

All Seville's came with the fuel-injected Olds 350 (unless it was a diesel), and this one actually still has it! There have been a number of Seville's in the country over the years although they were never officially sold here, but many were converted to carburetors. The service network that was in place here for US cars mainly dealt with Chevrolet trucks, Chevrolet G-series vans, Ford Econolines and the odd Caprice, they basically all had 350's (or 302's) and carbs, so no one was really capable of handling these fuel injected Seville's (or other fuel injected US cars of the era) here, so many were converted to whatever carburetor could be found - same with the diesel Oldsmobiles (that were actually sold here). Many were converted to gas V8's or simply junked.

...

Well, it may be hacked, but it's yours. There can't be that many to choose from in your region, so it might be easier to "Love the One You're With," as Stephen Stills said. Our '93 F-150 is pretty hacked, but I know how much worse it could be and how good the other stuff this truck has going for it is. Doubt we'll ever find another regular cab step side with a 3.55 trak-lok and a 351 for as affordable as this one was. So while your Roadmaster may not be what you want it to be right now, you have the opportunity to make it into what you want it to be.

Could you post pictures of the set up? How does it run? I've pretty much only seen the air cleaner with the EFI decals on it. The ones I've seen up close have had carb slaps.

[VicCrownVic]

Wiper motor assembly has a wheel inside with various tabs that mechanically handle parking somehow (see picture of taken apart wiper motor). I haven't stared at it enough to grasp how it works. I would think a mechanical issue, such as broken tab(s) on that wheel, would cause consistent incorrect behavior. If it's not consistent a bad switch like Kishy mentioned could be the culprit.
Neat thing about these wiper motors, you can actually use one from a later year, but you would need to do some swapping of electrical connectors and the mounting plat to make it work.
1991 uses the same wiper motor as 1988. RockAuto does have a 1 connector motor for 1991 but since it's more expensive and requires the same amount of work, you're better off getting a wiper motor for a later model, up to 2002. The electrical connecter would need to be harvested off of a later car (not 1991 as it originally had 2 connectors), mine came from a 1997 but any 1992-2002 should be a suitable donor. I realize this may not be as easy an option over there, but here in near Detroit that are plenty of donors in the junk yards. The wire colors did not change between the 1991 car that I installed the later motor on and the 1997 that the wire connector pigtail came from. So, splicing the single connector in place of the two was just same color wire to same color wire. The mounting plate is simple to swap, 3 bolts I think holds it on to the motor assembly.

https://www.grandmarq.net/vb/forum/technical/box-tech/electrical-and-wiring-hvac-vacuum-cfi/52045-wipers-and-horns?p=1226987#post1226987

Actually, forget about the later model retrofit, look at the 1992-1994 Grand Marquis listings on RockAuto. It shows a picture of the correct 2 connectors, but since it is listed for '92-'94 you will probably have to swap the mounting plate. Here's a pic of the original motor from my '91 MGM (The Ice Car):

[Tynnerstroem]

Thank you all very much for the wiper motor help! It seems for the time being to work, they park where they should so I'm thinking the switch may be getting tired. I'll definitely be keeping my eye on it now that the car starts to see more use.

DerekTheGreat I'll try to get some shots for you next time I'm out there! It basically looks like a two-barrel carburetor under there. The car doesn't run good at all currently. It cranks real good and fires right away but wants to die, even if you keep working the accelerator. If you do get past that it runs great on all seven cylinders. I remember we managed to get it to run on its own, after which it could be turned off and then back on with no issue an hour or two later. However the next day it was back to status quo, so we are speculating that one of the injectors is leaking fuel, making it hard to start after it has not run for like a day or more, but easy to start after just an hour or so, since it might not be leaking enough for it to be hard to start after relatively little time. We shall see.

I picked the Grand Marquis up today for tomorrows Cars & Coffee event - the last of the season, to be held at His Majesty The King's official residence (I know I know, old world shit but I'll give our King a pass - he's a car guy after all and has a vintage Shelby Mustang, a 1989 Grand Wagoneer and a vintage Porsche among other cool cars), a castle just outside of the city. Perfect environment! The drive home was wonderful and the car feels really good.






Sleeping soundly next to its FoMoCo brethren in my garage.