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Does 5W20 oil cause more engine wear

My 2010 Jeep Wrangler Owners Manual recommends 5W20 oil, no options for up or down a grade based on temperature or driving conditions.

What is the truth? Does this cause extra wear on engine components, just to get slightly better mileage? Is it better for the engine to run 10W30 in western Washington where the temp never drops below 0F or rarely climbs above 100F? Did Jeep actually redesign the engines to work with the lighter oil? What are the facts?

My 2002 F350 has had 5W20 in it since it was new. No noticeable signs of engine wear or additional oil consumption. I trust the Ford engineering and suspect that the Damiler/Chrysler/Jeep engineers went through similar testing to make sure it was OK.

I did not like 5-20 when vehicle manufacturers first started using it. In truth, it’s turned out to be a pretty reliable lubricant over the years. Jeep would not put an oil in a vehicle engine and jeopardize their standing among their loyal customers. I have owned Jeep Cherokees since the early 80’s and never had a lemon yet. Use the oil recommended in your owners manual and drive on in confidence.

This move was purely CAFE (fuel economy) driven. Yes, if you use a cheap non-synthetic oil in your Jeep and tow a heavy load or drive in extemely high temperatures (Death Valley) you will experience more engine wear, but the engine will last till the warranty is up!

For NORMAL driving in Western Washington, which has a near ideal climate for a car, 5W20 should be OK, but I would use a synthetic version.

My son lives in an extremely cold climate and his Ford-dictated oil viscosity is 5W20 in his Mazda. Instead, he uses 0W30 full synthetic, which covers him for all driving conditions.

I do not believe Chrysler has done anything to your Jeep engine to adapt it to 5W20. They likely tested it to make sure it did not fail within the warranty period.

Since most engine wear happens at start up, the sooner the oil gets circulating the better. The lighter weight oil helps that especially in cold weather.

The guys that designed the engine know better than any of us what’s the best oil to use in that engine. You ignore their recommendations at your own peril.

I agree…why do we keep trying to reinvent the wheel err, oil.

Yeah, just to clarify, almost every car on the road these days uses 5w-30. The 10w-30 should only be reserved for old (like 1970’s and earlier) cars. So in terms of cold-starts, where most engine wear occurs, the 5w-20 should perform exactly the same as what’s in most cars. The debate is whether it will protect as well at high temperatures.

I suspect there’s more than CAFE involved. Tolerances in today’s engines are kept much tighter than in engines of old. They vary far less.

One point too with modern engines is that many manufacturers now are using the oil almost as a hydraulic fluid to operate the variable valve timing systems. I know Honda does this. I’d be wary of making a general statement recommending a weight other than what the manufacturer recommends.

The engine in the Wrangler is hardly state of the art. My 2007 Toyota has variable valve timing and the original oil specified in the MANUAL was 5W30. Since then I received a bulletin that 5W20 is OK as well, and the dealer is pushing it since the NEW Toyotas are specified to use 5W20. So, draw your own conclusions.

I would not recommend 10W30 for OP’s engine, but if OP uses 5W20, I would go synthetic.

My son now has 70,000 miles on his Mazda 3 with 0W30 synthetic and the engine runs flawlessly and uses no oil!

I just purchased a 2011 Toyota Sienna that calls for 0W-20 oil. I think this engine was designed to use the lighter oil. I noticed that the sticker the dealer put on the windshield reminds me to change oil at 5000 miles and it specifies 5W-30. Since I own another Toyota (2003 4Runner), the dealer is providing 2 years of oil changes free since I am a “loyal” customer. I wonder what oil they will try to put in the crankcase when the van is ready for an oil change?

I think they put the same Valvoline sticker in the upper left corner of all cars, but I will certainly monitor the situation when it is time for an oil change.

The heaviest oil I ever saw put in a crankcase was in a 1950 Pontiac. One of my classmates in college had driven to a meeting at another campus with several of us in the car. A connecting rod started knocking in the old Pontiac straight 8 when we were about 20 miles from campus. We stopped at a filling station that was open and had the oil drained out and replaced with 90W gear lube. We did the remaining 20 miles at 15 miles per hour. A wrecker hauled the old Pontiac away the next day and it was never seen again.

They sell 3 weights of oil in Mexico…30, 40 and 50…“Multi-grade oil” means 20w-50 down here…5w-20 oil is simply not a salable product in Mexico…

Somehow all the “close tolerance” Ford F150, Focus, VW Passat, survive using these grades of oil…In the States, I would prefer 10/30 in my crankcase for temperatures above 90 degrees…YES these engines might run fine without damage using 5w-20, but I bet they will run fine on 10W-30 too and have a little safety cushion when the thermometer nears 100 degrees…

You can cause damage by using too heavy an oil in an engine DESIGNED for it. Rod and main bearings, variable cam timing sprocket mechanisms, and such , designed for 5w20 will suffer damage.
Other applications, such as those mpg boosters, will not.

Thanks Caddyman; Mexico does not have CAFE standards with penalties for not achieving them. I lived in the tropics for 5 years and all those 5W20 and 5W30 Toyotas and Nissans used 10W30, 10W40 or 20W50 over there. The lowest temperature at night was 25C or 77F.

Since cold starts in North America mean engine wear, a 0W30 or 0W40 oil would be ideal; it would have to be synthetic of course. Many VW oils are European spec 0W40.

Since most engine wear happens at start up, the sooner the oil gets circulating the better. The lighter weight oil helps that especially in cold weather.

That “start up” is the over used and misnomered marketing statement of Castrol. What they don’t tell you is that “start up” is the first (about) 20 minutes of operation. SAE defines it as anything other than “steady state”. It take 12-15 miles or 20 minutes to fully thermally saturate the engine. It’s not just the coolant temp. The oil temp is much slower to rise.

“Cold start wear” (and by that I mean EVERY cold start, even if it’s @ 100F) has unavoidable wear involved. You get wear from ill fitment of the pistons, you have anti wear additives in the oil that can’t react very quickly @ <180F …and you have corrosive formations with combustion byproducts that react with the moisture that is formed by the combustion process (you make about 1.4 gallons of water @ sea level for every gallon of gas you burn). When it condenses, it will form acids that micro etch the cylinder walls …or so I’m told.

5w-20 will cause more wear than a heavier oil in some absolute sense. What most can’t figure out is that the difference is between a potential 500k gas engine vs. a potential 450k engine. When’s the last time you heard of an engine seizing? Now I’m sure you’ve heard of a timing chain wearing in advanced mileage on some engine, but that engine was surely on a 30 weight …what’s its excuse?

Most of the higher friction/rubbing points have been eliminated with rollerized cam followers. They don’t need the added film strength of heavier oils.

From the 70’s when it was introduced, most of you who ran 5w-30 were running a 20 grade anyway. You just didn’t know it. 5w-30 would shear to the 20 weight base stock in a short amount of time. Now they’re much better, but still shear. They just don’t typically go out of grade.

The new(er) evolution to 5w-20 only differed in that the stuff was a 20 grade while in the bottle. Better base stocks …better additive packages and ever advancing refining/processing technology did the rest.

Many will cite the differences in places like Australia and Europe. Note that most of the OEM mileage recommendations for US cars are pretty short. Ford started off with 5000 miles. Now they’ve lengthened it, but they had about 5 years of “in the field/real world” experience to bolster the move. GM, with their 5w-30 recommendation, was always at 7500/6months for normal duty(without an OLM).

Think of it this way, when you buy a 3/4 ton Chevy with a small block, and you tow, does Chevy say “Use a 40 weight!! You’re going to see peaked oil temps and that will mean thinner oil!!!”. NOPE. They tell you to shorten the oil change interval. That’s what most of the domestics did when they went to 5w-20. Short intervals.

…but on to CAFE. CAFE never saved one drop of gasoline. It made auto manufacturers produce MORE UNITS. More steel, more tires, more plastic, energy, and more financial resources were consumed. It kept many pipelines filled with cash …and that’s all.

Neither me nor any of my family members run 5W20 oil in any vehicles in the OK summertime. It’s just our personal preferences but on a typical summer day here 5W comes out of the container like water.

We generally run 10W40 in the summer, 10W30 in the winter, and have never suffered any problems whatsoever by doing this; no matter what the factory recommendation is.
On higher mileage engines (250k, etc.) we run 20W50 in the summer on the vehicles that do not see many short hops.

Thanks for all the replies, unfortunately not what I was hopeing for. Any Jeep engineers out there? Do I trust Chrysler Marketing and Finance people, nope. So I’m not convinced they care about what happens to my Jeep 150K miles from now. If it makes them a buck at my expense? Will my Jeep make the 36K warranty? no doubt, but I typically take care of my cars and own them for a long time. (1980 Honda Civic, 285K, original engine, changed oil at 7500 miles with no problems, 1998 Dodge Grand Caravan, just sold it with 199K on original engine, change interval 6000 - 7500 miles. Good old 10W30 in both). These are facts to me, with first hand knowledge. I’m getting lots of opinions on both sides of the argument, what I’d really like is facts to back them up. Do I trust engineers, somewhat, I r 1. How about the Fords in the UK. I’ve heard they don’t specify 5W20. Are the engines actually different? How about any cars selling in Mexico? Are they different than their US counterparts? I’m not trying to offend anyone here, just looking for data because I love this Jeep and I want it to last a long time.

I sense the OP (Joeflaps) is asking if he doesn’t switch to a heavier weight oil, will his engine life suffer.

I’ve never seen any evidence of a shortened engine life when the oil weight recommended by the manufacturer is used. If anyone here has, I’d be interested in the details.

The only place that you can get the facts as you want is from an engine designer or the people who test engines. Everyone else has an opinion from their particular experience so here is mine:

Our two recent model GM cars specify 5W-30 per GM Standard GM6094M which is a synthetic. Apparently GM may have recognized shortcomings in garden variety synthetics and has forced an improvement for their engines. This might be stated negatively by saying that GM engines have a weakness so extra good oil is needed to offset that but I doubt it.

At first, the only oil that met GM6094M was Mobil 1. Now there are others. I am looking at the label on a recently purchased 5W-30 Mobil 1 container. It says "Approved by General Motors and Honda against their high-performance engine oil specifications: GM 4718M and Honda/Acura HTO-06. It also says: “Suitable for use in all gasoline and turbocharged engines which require the following specifications: Chrysler MS-6395, GM 6094M and Ford WSS-M2C929-A”.

With credentials like that, you should be OK with Mobil 1 5W-30 or any other 5W-30 synthetic with similar specifications as a change from 5W-20.

The oil described on the oil fill cap and in the owner’s manual is the weight that was in the engine when the mfg ran the fuel economy tests.

I found an article on one of the oil forums (can’t be more specific) a few years ago when my '04 Civic was new that said that Honda went from 100K+ life to 70K or so engine life when they changed to 5W-20 from 5W-30.

So to answer the OP, yes, it causes extra wear, and yes, it was to get better mileage.