Conventional oil or synthetic oil?
 

I've got a 2007 Grand Marquis LS with 93,000 miles on it. Should I use conventional 5w20 oil or synthetic oil. 5w20 is like water. Any recommendations? I've been using conventional 5w20 Quaker State oil right along without any issues.

Thanks, Tom.

I have 2005 Grand Marque Ultimate Edition with 26,000 miles and I only run Synthetic oils.
All the cars I've owned only Synthetic Oils.... even my motorcycle.

I run a little thicker 5w30 or 40 since I'm in Hawaii and the tempts rarely drop below 60 degrees outside.
My two corvettes I used to tear down after racing and the insides were super clean every time we tore down after a race.
Kept all the rubber seals in top shape too......

Run Synthetic 3,000 miles change the oil and filter out to flush out the residual natural oil the fill her up and watch how clean the inside will remain if you ever tear down.

Aloha,

Realistically, any 5w-20 is atleast a synthetic blend anyway. I would continue using what you are presently using, nothing wrong with it. I stick with the weight (5w-20) recommended by the manufacturer. Most of the time, I use Pennzoil yellow bottle, which is made by the same company as the QS you are using. If I come across a deal on any name brand 5w-20, I go with it.No brand loyalty for me. Some say their engine "likes this brand" which is pure non-sense.

First response
 

I just acquired a 2009 Mercury Grand Marquis LS with 233,002 miles on it. Never had anything but Valvoline Synpower 5w20 and the oil at 3k miles is all but new looking. I have run Valvoline, Mobil 1, Pennzoil and Kendall (Phillips Petroleum) synthetics since 1989 and never had a problem. My main driver is a 2018 Nissan Titan and it called for 0w20 but I was left with several cases of Kendall Liquid Titanium 5w20 from a previous set of Fords I had. Works fine and at 40k miles uses no oil. There is a reason 5w20 is virtually impossible to find in conventional motor oil. The automakers have designed engines since he late 80's/early 90's to run on very thin lubricants for cooling/cleaning/carbon dispersion and anti sludging. Stick with the thin stuff, it works better.

Conventional or Synthetic !??
 

Your Grand Marquis owner's manual specifies 5-W-20 CONVENTIONAL engine oil -- which is what you've used so far, with "no issues".
However, much has changed in engine oils since 2007, and the conventional oils have been superceded by the synthetic oil's technological advancements.
For example, Pennzoil has come out with an oil made from Natural Gas -- and the new API designation is "SP".
As a desert dweller, I pay close attention to engine temps and oil pressure -- and enjoy long-distance, high-speed cruising through the deserts and moun tains of the American West.
The famous 95 MERC presently has 171,500 miles on the clock, and runs Pennzoil Ultra Platinum, 5-W-20; Bosch Premium Oil Filter #3410; and a FILTERMAG #SS365PR Magnet Kit, with oil and filter changes at 5,000 miles.
I use the Pennzoil Ultra Platinum because it tests well, it's available almost everywhere, and the cost is reasonable.
I use the Bosch #3410 because it's a 20-micron filter, it's available almost everywhere, and the cost is reasonable.
I use the FILTERMAG # SS365PR Magnet Kit, because it's the largest (11.4 sq.ins) kit, has heat-stabilized magnets, and lasts a lifetime, which makes the initial cost reasonable.
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'95 MERC at Flaming Gorge, UTAH
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Smooth Power, Excellent handling.
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"Italian Lace" Wheels.
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Bosch Ignition Wires - With Loom Clips

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Custom Dual Exhaust Exits
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95 MERC Engine Bay