New 2004 Grand Marquis
 

Hey everyone, I just recently bought a 2004 marquis LS. It currently has 83,000 miles on it. After about a week of owning it, I had to send it in for a transmission rebuild, but since then, it runs excellent. What can I do to keep it properly maintained? Should I run synthetic oil in it? Anything that should be changed at this period in its life?
thanks everyone

Surprised to hear about the tranny at such low mileage. What was it doing?

No, you do not have to run synthetic no matter what others tell you, just make sure your oil meets Ford spec WSS-M2C945-A. But I have seen many synthetics on sale at dino prices which would steer me towards synthetic at that time and I would go further on that oil change.. If you accrue a lot of miles in a short time, synthetic will help you, so you are not changing oil every month. Best advice is to follow your manual and use the weight of oil specified or what is shown on the fill cap. I believe it is 5W-20. Stick with any name brand product and you will be fine, you will get advice on brands from former sales reps on this forum which are based on opinions not facts telling you this is what is best for a G.M. If in doubt, go OEM..

When I get a used car, I will change tranny fluid/filter, fuel filter and air filter if needed. I will attend to these about every 40k miles. If your plugs are original, you are nearing the time for replacement.Remember, that is just my opinion based on my driving style.

Hello, Cbray1, and welcome to the Mercury Forums --
Congrats on your "new" 2004 Marquis LS.
You inquired about servicing your vehicle, and it helps to know what sort of climate and type of driving that we're dealing with, as Factory-Recommended Service Intervals vary.according to driving conditions and vehicle use.
Generally, when buying a new vehicle, it's best to check and do the important stuff -- Air Filter, Fuel Filter, Oil Change and Filter, Brake Fluid, Trans Fluid Level (MUST NOT over-fill!), and Differential Fluid Level.
FOMOCO calls for 5-W-20 engine oil that meets Ford Spec # WSSM2C945-A -- BUT that spec is now obsolete. It has been superseded by #WSSM2C946-A.
It really doesn't matter much, because nearly ALL oils currently on the market exceed the specs from 2004, Including house-brand oils from Wal-Mart and/or Amazon. The proper VISCOSITY is what's most important. Novices often use "heavier" oil, thinking that it "lubricates better" -- but it doesn't.
I'm long retired and have a plenty of time to research -- I live in the desert, and The 95 MERC is built for and used as a long-distance, high-speed touring sedan -- throughout the mountains and deserts of the American West. Due to my driving style and conditions, I often substitute aftermarket parts and/or police/severe-service parts, such as brakes and shocks.
Since the entire fuel management system on The 96 MERC is a result of a FORD/BOSCH design partnership. I use Bosch parts in place of OEM in some instances -- Fuel Pump, Fuel Injectors, Iridium Plugs, Mag-Core Ignition Wires (you don't have ignition wires), and I stick with OEM for things like the Air Conditioning Compressor -- but I take out the "factory" compressor oil, and use BEHR PAO Oil that's made in Australia -- in 24/7 mining operations, under blistering conditions.
I use and recommend the BOSCH #3410 Oil Filter for price, availability, and it's 20-micron filtering ability.
HOWEVER, a true 20-micron filter needs to be changed at 5,000-mile intervals -- which I do, and change the oil every 10,000 miles.
If you live in a colder climate, like Chicago or Cleveland, you may wanna change your oil more often.

Yes, OEM is always the "safe bet" -- BUT​​​​​​ -- over time, OEM parts build up a reliability factor, and sometimes need an up-grade to an aftermarket part that was not even made at the time our cars were assembled. Those Bosch Mag-Core ignition wires are a perfect example, as the OEM carbon-core wires were PRONE to failure, and the Bosch wires have functioned perfectly for several years..
Of course, those ignition wires do not concern you, as your Marquis has the Coil-On-Plug type of ignition.
If you're lucky, you MAY be able to find a set of Factory Service Manuals -- 2 books, 1 General Service, the other Emissions and Electrics.
I found a set on e-bay for 40 dollars -- worth every penny !
Anyways, I'll help ya any way I can -- but it helps a lot to have your location (nearest big city).
I do almost all of my own work -- at home -- in the carport. It's fun !!
Next up -- Change the intake manifold gaskets, using Fel-Pro #MS98007T-1 gasket set.
Change fuel injectors from OEM Ford/Bosch to Bosch Series 3 - 19-lb/hr.

https://cimg6.ibsrv.net/gimg/www.mer...eefc8accce.jpg
Sleeping Beauty; Rolling Thunder.

Ford spec WSSM2C946-A replaces WSS-M2C929-A which only applies to 5W-30 weight oil. Spec WSS-M2C945-A applies to 5W-20 weight oil and is a current spec used today for engines using 5W-20.

Do your own research and don't take things too seriously from a BOSCH sales rep, past or present.

Thanks, Raski -- I stand corrected on that oil spec -- I was reading the 5-W-30 specs, not noticing that the 5-W-20 specs are different.
I see you're still obsessing over BOSCH products and/or ME, and it's hilarious !! You should be in the Olympics -- as a Conclusion-Jumper !!
Your stubbornly ignorant notion that I am (or was) involved with the advertising, manufacture, or sale of BOSCH products is comical in it's ridiculousness.
I have never worked for BOSCH, or for any company that makes or sells their products. Period.
You can STOP with your grossly inaccurate assumptions at any time.
Thank you.
https://cimg1.ibsrv.net/gimg/www.mer...ef1a61aa0c.jpg
95 MERC at Flaming Gorge, Utah.