Year: 1997 Make: Mercury Model: Mountaineer Mileage: 179,000 Transmission: Automatic
Engine: V8 5.0L
Hello everyone
When my father used this SUV he always put 10W-30 because it "helps to create a seal between the piston rings and cylinder walls when the engine is old". I'm a "by the book" kind of guy and after going through the maintenance section on the owner's manual it states "Engine oil with an SAE 5W-30 viscosity and displaying the API certification mark are preferred for your vehicle. They provide the best engine performance, fuel economy, and engine protection for all climates down to -25°C (-15°F)". I live in NC; during the winter season the coldest it's ever gotten was 16°F (-8°C).
The owner manual does not contain an oil chart but the Haynes repair manual does and provides an oil chart that shows 10W-30 can be used, but this is mainly for Ford Explorer. It just happened to cover Mercury Mountaineer.
Personally, I would service the recommended oil viscosity, but we have a lot of 10W-30 laying around and oil is a bit expensive. If necessary I won't hesitate to buy it. What do you guys think?
Also, can 10W-30 cause more harm than good for the engine where the manufacturer specifically states 5W-30?
Thanks
Ah I see!
That sticker was probably put there at the factory. So if you look at the sticker on the door jamb, it should tell you the date when the vehicle was manufactured.
If you look on the first few pages of your manual, there should be a date when it was published.
Go with the most recent recommendation. But as I said before ... I don't think it will make a huge difference.
helps to create a seal between the piston rings and cylinder walls when the engine is old
that's a bit dubious, since both oils are 30 weight at operating temperature. The 10w30 is thicker when cold. Not what you want for the winter. You want the thinner 5w30 so it fills the upper engine as quickly as possible on engine startup.
Those older cars were less picky about oil weight than modern ones. My old Grand Prix would also take 5 or 10 depending on ambient temps. But if it doesn't leak or burn oil, there's really no reason to exclusively use 10. But if you want to use up old inventory when it warms up, I see no issue with that either.
The owner manual does not contain an oil chart but the Haynes repair manual does and provides an oil chart that shows 10W-30 can be used, but this is mainly for Ford Explorer.
The car's new enough to not have those temperature graphs. The metallurgy is much improved from the old days and oil is also much better refined than before.
Also, can 10W-30 cause more harm than good for the engine where the manufacturer specifically states 5W-30?
It won't destroy the engine right away, but it will increase wear and tear while the engine is warming up. Once it's hot, it'd be fine. 10W is slightly thicker than 5W. The oil pump needs to work harder to pump cold 10W oil, taking more time for it to get to parts. The wear will eventually add up over thousands of miles, especially if you do a lot of short trip driving where the engine doesnt get up to operating temperature.
They specified a lighter oil, knowing there's a tiny difference in the two oils. The fact they took it to exact specifications from the way they used to make engines should be a good indicator of how well designed and selected oil weights are these days.
You could throw a quart in with every 4 or 5 quarts 5W-30 to use it up. That'll keep the additional wear to a minimum while using up your inventory.
Thank you for this. Winter is coming so I will service the engine with 5W-30.
Year: 97 Make: Mercury Model: Mountaineer Mileage: 179K Transmission: Auto Engine: 5.0L V8
Hello everyone
Recently I serviced my SUV with 5W-30 in accordance with the owner's manual. I overlook the "important vehicle information" sticker which says to use 10W-30. Now I'm scratching my head on which oil is best for my engine. I don't understand why the manufacturer says to use 5W-30 but on the sticker say to use 10W-30. I'm guessing the information has been revised over the years by the manufacturer and now recommends 10W-30.
Any advice?
Thanks
where is this sticker and where did it come from?
1. Located on a frame in front of the radiator.
2. Came from Ford motor company.
Note: I can't find the option to upload the image. I'll figure something out.
https://photos.app.goo.gl/v5PLRD48LrcjwZRT8
The link above should show the "important vehicle information" sticker. Hope it helps.
it's a private link. Nobody can use it but you.
Read the topic called "Read this first" on the main page for posting images.
I don't see many vehicles with this sticker. Does this mean when it comes to oil viscosity, I should only use 10W-30 since the manufacturer revised it?
Thank you in advance.