Gas engine life today vs yesterday?

[Presentation]

For years Mercury told us to use 25w-40 Mercury traditional motor oil for our gas stern drives. The general rule of thumb was with normal use and following the recommended service guide a gas stern drive would make it 1,500 hours. Some more, some less, but average 1,500 hours before needing rebuilding or replacement.


A few years ago they changed their recommendation to Mercury Synthetic Blend Oil 25w-40. Well it did not take long, now Mercury is recommending we use Mercury Full Synthetic 20w-40 oil. If you did not know it, mercury has a service bulletin to make this recommendation retroactive to existing gas stern drives.

My question is, with the advancement in this modern Full Synthetic 20w-40 oil what is a new reasonable life expectancy of a gas stern drive?

 

[Presentation]

So far, this is all I could find.

This article is about a test done comparing various engine oils in New York taxicabs. Basically, all major oils worked fine. Oil additives were of no measurable benefit and the additional cost of synthetic oils was of no measurable benefit.


Consumer Reports ArticleThe surprising truth about motor oils July 1996, pp 10-13 - yes ,14 years ago.

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Our 4-1/2-million-mile test with a fleet of New York City taxicabs turned some conventional wisdom on its head.

Mobil commercial claims its oil "has been in more Indy 500 winners than any other oil." Quaker State shows an engine with a terminally corroded inside what they imply could happen when you use another oil. Exxon's commercial for its Superflo oil urges motorists to "rely on the tiger."

Oil companies spend millions of advertising dollars each year to convince you that their oil can make your car's engine perform better and last longer. And purveyors of motor-oil and engine "treatments" assert that their products offer engine protection that oil alone can't provide. In our most ambitious test project ever, we set out to discover whether such claims are fact or fancy.

One way to gauge the performance of motor oils is to test them on the road. We did just that, using a fleet of 75 New York City taxicabs. Indeed, the oil industry itself tests its oils in New York City taxis.

For 22 months, we tested the performance of 20 popular motor oils. Each of those oils met the industry's latest standards, as certified by a starburst symbol on the container. (See "It's not just oil," article 3 of 4.) We also tested Slick 50 Engine Treatment and STP Engine and Oil Treatments.

In addition to the taxicab tests, we had the oils' chemical and physical properties analyzed by an independent lab. We also surveyed our subscribers about their oil-changing experiences and preferences, and we sent shoppers to quick-lube centers across the country to assess the service. Finally, because changing the oil is just one part of car care, we've reviewed some other ways you can help keep your car running longer. That report begins on page 18 (not included in this e-mail).
Testing the oils

We put identical rebuilt engines with precisely measured parts into the cabs at the beginning of the test, and we changed their oil every 6,000 miles. That's about twice as long as the automakers recommend for the severe service that taxicabs see, but we chose that interval to accelerate the test results and provide worst-case conditions. After 60,000 miles, we disassembled each engine and checked for wear and harmful deposits.

Our test conditions were grueling, to say the least. The typical Big Apple cab is driven day and night, in traffic that is legendary for its perversity, by cabbies who are just as legendary for their driving abandon.

When the cabs aren't on the go, they're typically standing at curbside with the engine idling - far tougher on motor oil than highway driving. What's more, the cabs accumulate lots of miles very quickly, making them ideal for our purposes. Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service - stop-and-go city driving.

Each of the 20 oils we studied was tested in three cabs to provide meaningful test results even if a few cabs fell out with mechanical problems or because of accidents. (Six of the 75 engines did, in fact, have problems, none apparently related to the oil's performance.) For a detailed description of our test procedures, see "Testing in the Big Apple," article 2 of 4.

Our shoppers all across the country bought hundreds of quart containers of oil. Some brands had slightly different formulations in different areas, but all the oils included a full package of additives.

The independent lab helped us identify the most representative formulations of each brand. Our engineers transferred containers of that oil to coded 55-gallon drums and hauled them to the fleet garage for testing.

Ideally, oil should be thin enough to flow easily when the engine is cold and remain thick enough to protect the engine when it's hot. The lab analyses of each oil's viscosity characteristics - its ability to flow-indicate that motor oils have improved since 1987, when we last tested them. This time, far fewer test samples failed to meet the viscosity standards for their grade - and those were typically outside the limits by only a slight amount. No brand stood out as having a significant problem.

We tested oils of the two most commonly recommended viscosity grades - 10W-30 and 5W-30. Automakers specify grades according to the temperature range expected over the oil-change period. The lower the number, the thinner the oil and the more easily it flows.

In 5W-30 oil, for example, the two numbers mean it's a "multiviscosity" or "multigrade" oil that's effective over a range of temperatures. The first number, 5, is an index that refers to how the oil flows at low temperatures. The second number, 30, refers to how it flows at high temperatures. The W designation means the oil can be used in winter.

A popular belief is that 5W-30 oils, despite their designation, are too thin to protect vital engine parts when they get hot. However, one of our laboratory tests measured the viscosity of oils under high-temperature, high-stress conditions and found essentially no difference between 5W-30 oils and their 10W-30 brand mates. But at low temperatures, the 5W-30 oil flowed more easily.

Viscosity grade is important, so be careful. Recommendations vary with the make, engine, and model year of the car, so check your owner's manual and ask the mechanic for the proper grade of oil.

Of the 20 oils we tested, nine were conventional 10W-30 oils, and eight were 5W-30. We also tested two synthetic oils, Mobil 1 and Pennzoil Performax, and one synthetic-and conventional blend, Valvoline DuraBlend; all three were 10W-30 oils.
No brand performed best

If you've been loyal to one brand, you may be surprised to learn that every oil we tested was good at doing what motor oil is supposed to do. More extensive tests, under other driving conditions, might have revealed minor differences. But thorough statistical analysis of our data showed no brand-not even the expensive synthetics-to be meaningfully better or worse in our tests.

After each engine ran about 60,000 miles (and through 10 months of seasonal changes), we disassembled it and measured the wear on the camshaft, valve lifters, and connecting-rod bearings. We used a tool precise to within 0.00001 inch to measure wear on the key surfaces of the camshaft, and a tool precise to within 0.0001 inch on the valve lifters. The combined wear for both parts averaged only 0.0026 inch, about the thickness of this magazine page. Generally, we noted as much variation between engines using the same oil as between those using different oils. Even the engines with the most wear didn't reach a level where we could detect operational problems.

We measured wear on connecting rod bearings by weighing them to the nearest 0.0001 gram. Wear on the key surface of each bearing averaged 0.240 gram - about the weight of seven staples. Again, all the tested oils provided adequate protection.

Our engineers also used industry methods to evaluate sludge and varnish deposits in the engine. Sludge is a mucky sediment that can prevent oil from circulating freely and make the engine run hotter. Varnish is a hard deposit that would remain on engine parts if you wiped off the sludge. It can make moving parts stick.

All the oils proved excellent at preventing sludge. At least part of the reason may be that sludge is more apt to form during cold startups and short trips, and the cabs were rarely out of service long enough for their engine to get cold. Even so, the accumulations in our engines were so light that we wouldn't expect sludge to be a problem with any of these oils under most conditions.

Variations in the buildup of varnish may have been due to differences in operating temperature and not to the oils. Some varnish deposits were heavy enough to lead to problems eventually, but no brand consistently produced more varnish than any other.

The bottom line. In our tests, brand didn't matter much as long as the oil carried the industry's starburst symbol (see "It's not just oil," article 3 of 4). Beware of oils without the starburst; they may lack the full complement of additives needed to keep modem engines running reliably.

One distinction: According to the laboratory tests, Mobil 1 and Pennzoil Performax synthetics flow exceptionally easily at low temperatures - a condition our taxi tests didn't simulate effectively. They also had the highest viscosity under high-temperature, high-stress conditions, when a thick oil protects the engine. Thus, these oils may be a good choice for hard driving in extreme temperatures.

Note, too, that a few automakers recommend specific brands of motor oil in the owner's manual. You may need to follow those recommendations to keep a new car in warranty.
Oil changes: How often?

The long-time mantra of auto mechanics has been to change your oil every 3000 miles. Most automakers recommend an oil change every 7,500 miles (and a specific time interval) for "normal" driving, and every 3,000 miles for "severe" driving - frequent trips of less than four or five miles, stop-and-go traffic, extended idling, towing a trailer, or dusty or extremely cold conditions. Many motorists' driving falls into one or more of those "severe" categories.

In our survey, almost two-thirds of our readers said they had their oil changed every 3,000 miles or less. They may be following the thinking expressed by one of our staffers: "I have my oil changed every 3,000 miles because that's what my father did, and all his cars lasted for many years."

To determine whether frequent oil changes really help, we changed the oil in three cabs every 3,000 miles, using Pennzoil 10W-30. After 60,000 miles, we compared those engines with the engines from our base tests of the same oil, changed every 6,000 miles. We saw no meaningful differences. When Mobil 1 synthetic oil came out, Mobil presented it as an oil that, while expensive, could go 25,000 miles between changes. That claim is no longer being made. But Mobil 1 is still on the market, selling at a premium (along with pricey synthetic competitors from several other companies). And synthetic oil's residual reputation as a long-lasting product may still prompt some people to stretch their oil changes longer than the automaker recommends.

Determining whether synthetic oils last longer than conventional ones would require a separate test protect. To try to get some indication, we put Mobil 1 synthetic into three cabs and changed their oil every 12,000 miles.

We intended to compare the results of these tests with those from the three taxicabs whose Mobil 1 was changed at our normal interval, every 6,000 miles. Unfortunately, two of the three engines using the 12,000-mile interval developed problems. (We couldn't attribute those problems to the oil.) The third engine fared no worse than the three whose oil had been changed at 6,000-mile intervals.

The bottom line. Modern motor oils needn't be changed as often as oils did years ago. More frequent oil changes won't hurt your car, but you could be spending money unnecessarily and adding to the nation's energy and oil-disposal problems.

Even in the severe driving conditions that a New York City taxi endures, we noted no benefit from changing the oil every 3,000 miles rather than every 6,000. If your driving falls into the "normal" service category, changing the oil every 7,500 miles (or at the automaker's suggested intervals) should certainly provide adequate protection. (We recommend changing the oil filter with each oil change.)

We don't recommend leaving any oil, synthetic or regular, in an engine for 12,000 miles, because accumulating contaminants - solids, acids, fuel, and water - could eventually harm the engine. What's more, stretching the oil-change interval may void the warranty on most new cars.
Testing Slick 50 and STP

We also tested Slick 50 and STP Engine Treatments and STP Oil Treatment, each in three cabs. (Slick 50 costs $17.79 per container; STP Engine Treatment has been discontinued.) All three boast that they reduce engine friction and wear.

The engine treatments are added with the oil (we used Pennzoil 10W-30). They claim they bond to engine parts and provide protection for 25,000 miles or more. We used each according to instructions.

The STP Oil Treatment is supposed to be added with each oil change. It comes in one formulation (black bottle, $4.32) for cars with up to 36,000 miles, another (blue bottle, $3.17) for cars that have more than 36,000 miles or are more than four years old. We used the first version for the first 36,000 miles, the second for the rest of the test-again, with Pennzoil 10W-30.

When we disassembled the engines and checked for wear and deposits, we found no discernible benefits from any of these products.

The bottom line. We see little reason why anyone using one of today's high-quality motor oils would need these engine/oil treatments. One notable effect of STP Oil Treatment was an increase in oil viscosity; it made our 10W-30 oil act more like a 15W-40, a grade not often recommended. In very cold weather, that might pose a risk of engine damage.
Recommendations

None of the tested oils proved better than the others in our tests. There may be small differences that our tests didn't reveal, but unless you typically drive under more severe conditions than a New York cab does, you won't go wrong if you shop strictly by price or availability. Buy the viscosity grade recommended in your owner's manual, and look for the starburst emblem. Even the expensive synthetics (typically, $3 or $4 a quart) worked no better than conventional motor oils in our taxi tests, but they're worth considering for extreme driving conditions high ambient temperatures and high engine load or very cold temperatures.

On the basis of our test results, we think that the commonly recommended 3,000-mile oil-change interval is conservative. For "normal" service, 7,500-mile intervals (or the recommendation in your owner's manual) should be fine. Change the oil at least that often to protect your engine and maintain your warranty. Even for the severe service experienced by the taxis in our tests a 6,000- mile interval was adequate. But some severe service - frequent cold starts and short trips, dusty conditions, trailer towing - may require a shorter interval. Note, too, that special engines such as diesels and turbos, which we didn't test, may need more frequent oil changes.

We don't recommend stretching the change interval beyond the automaker's recommendations, no matter what oil you use. Engine combustion contaminants could eventually build up and harm engine parts.

As for STP Oil Treatment, STP Engine Treatment, and Slick 50 Engine Treatment, our advice is simple: If you use an oil with the starburst symbol, you don't need them.

 

[Four Suns]

How many gas boat engines (or car engines for that matter) have you seen "fail" due to oil/lubrication issues? Not many.... Usually the cooling system fries them.

 

[Alex F]

I don't know the answer or heard an inspiring advantage for marine engines, but for cars the switch to syntetic oil was advertised with suggested oil change withing 10,000 miles. So, besides having as "they" say better oil for the engine you're now saving on routine maintenance compare to regular 3,000 miles oil changes for traditional oil.

For the past 15 years I was pretty happy with the brand I use and 3K miles didn't bother me. So, one car I have still uses this traditional oil while my other car must be used with syntetic since it's required by the manufactory.

It'll be interesting to hear if someone knows some details on marine engines.

 

[Alex F]

How many gas boat engines (or car engines for that matter) have you seen "fail" due to oil/lubrication issues? Not many.....

100% true! As long as the engine has clean oil it'll function just fine unless other components/variables contribute to a failure.

 

[MonacoMike]

Great read. Thanks!!!

 

[rondds]

I could be wrong but I seem to remember that the Merc manual that came with my 2002 Crownline (350 Mag Horizon and Bravo 3) stated specifically that synthetics were contraindicated. I understand that, as Scott said above, the service bulletin is retroactive to all gasoline engines, but it kinda reinforces in my mind what CU stated; ie: change your oil at the interval Rx by the manufacturer and you'll be just fine.

As for the interval, there was recently something in the media that debunked the "3000 mile rule." I don't know the source of that report but it does support what CU reported in 1996.


5 minutes later:
http://www.nytimes.com/2010/09/11/your-money/11shortcuts.html

Here's one for you tree-huggers...
http://autos.yahoo.com/articles/autos_content_landing_pages/586/the-3000-mile-oil-change-myth/

 

[andyr]

I've seen several reports that say boat engines fail at 1200 hour on average. Mine quit at 1190. Water in the engine. The cast iron seems to rot. Lots of scale. Parts of the intake manifold were so thin a screw driver would push through it. Everyone around here uses 30 wt oil.

 

[terminaldegree]

How many gas boat engines (or car engines for that matter) have you seen "fail" due to oil/lubrication issues? Not many.... Usually the cooling system fries them.

Agreed. When I spent my summers pumping gas in my teenage years at the local marina, I remember waiting on a few gas inboards continuing to give good service on the original motors at > 2000 hours, and several with at least 1500. Being in a freshwater area, it was not often I'd see rotting manifolds and risers like I read about on saltwater boats.

I'm curious to see what the new "norm" will become, or whether lubrication related failures will increase with some of the stratospheric cruising rpms people need to run (mostly due to heavy boats spec'd with marginal power from the factory).

 

[Presentation]

Merc says this.....

Service Bulletin
Bulletin No. 2008-01
2008-01 FEBRUARY 2008 © 2008 Mercury Marine Page 1 / 2
Oil Requirements for Gasoline Engines and Preventing
Contamination of Engines with Emissions Control.

Models Affected
Model Serial Number Range
Gasoline Sterndrive All
Gasoline Inboard All
Gasoline Tow Sports All
Gasoline Sterndrive with Emissions Control All
Gasoline Inboard with Emissions Control All
Gasoline Tow Sports with Emissions Control All

Situation
The following crankcase oil recommendation includes newly available engine oils, and supersedes all previous crankcase oil recommendations for MerCruiser gasoline engines.

This service bulletin contains the best available recommendation from Mercury Marine as of February 2008. If the owner's manual, which is updated from time to time, is not consistent with recommendations made in this bulletin, follow the recommendation of this bulletin.

Newly introduced engine packages with Emissions Control have catalysts that will be rendered ineffective if they become contaminated with certain elements or compounds.

These packages require special lubricants as described in this bulletin.

Engine Oil Recommendations for MerCruiser Gasoline Engines
For optimum engine performance and maximum protection use the following oil: Application Recommended Oil,

All MerCruiser engines Mercury MerCruiser Full‑Synthetic Engine Oil, 20W‑40, NMMA FC‑W rated

IMPORTANT: Lubrication requirements for catalyzed engines differ from the requirements for non‑catalyzed engines.

Some marine‑grade lubricants contain high levels of
phosphorus, which can damage the catalyst system on MerCruiser engines. Although these high‑phosphorus lubricants may allow acceptable engine performance, Exposure over time will damage the catalyst. Catalysts damaged by lubricants containing high levels
of phosphorus may not be covered by the MerCruiser Limited Warranty.

Oil Requirements for Gasoline Engines and Preventing Contamination of Engines with Emissions Control Page 2 / 2 2008-01.

If Mercury MerCruiser Full‑Synthetic, 20W‑40 oil is unavailable, use the following
lubricants, listed in order of recommendation. If you are servicing a catalyst engine, use
these for short periods of time only.

1. Mercury/Quicksilver 25W‑40 Synthetic Blend, NMMA FC‑W–rated 4‑cycle MerCruiser oil.

2. Mercury/Quicksilver 25W‑40, NMMA FC‑W–rated 4‑cycle MerCruiser oil.

3. Other recognized brands of NMMA FC‑W–rated 4‑cycle oils.

4. A good‑grade, straight‑weight detergent automotive oil according to the last row of the operating chart below.

NOTE: We do not recommend non‑detergent oils, multi‑viscosity oils (other than as specified), non FC‑W–rated synthetic oils, low‑quality oils, or oils that contain solid additives.

Mercury Full-Synthetic MerCruiser Engine Oil, 20W-40, NMMA FC-W rated.

MerCruiser/Quicksilver 25W-40 Synthetic Blend, NMMA FC-W rated 4-cycle MerCruiser oil.

Mercury/Quicksilver 25W-40, NMMA FC-W rated 4-cycle MerCruiser oil

See chart for AIR TEMPERATURE ORDER OF PREFERENCE for other recognized brands of NMMA FC-W rated oils
SAE 20W (32° F) 0° C
SAE30W (50° F) 10° C
SAE40W + (50° F) 10° C

Preventing Contamination of the Emissions Control System.
Catalyst and oxygen sensors can become contaminated, leading to component failure.

Phosphorus, found in some marine‑grade oils, and other compounds will damage or destroy a catalyst's ability to clean the exhaust. Catalyst‑friendly oil, like Mercury Full
Synthetic MerCruiser Engine Oil, prevents this damage. Approved synthetic oils must be used in MerCruiser engines with emissions control.

Acetoxy silicone sealants and other compounds in the exhaust stream can damage oxygen sensors and catalysts. Do not use non‑approved compounds and sealants. Oxime silicone sealants and Loctite 587 High Performance Blue can be safely used with catalyzed engines.

Fiberglass, a silica‑based material, can contaminate the catalyst and the oxygen sensors. To reduce the possibility that the engine will ingest harmful fiberglass and thereby poison the emission control components, protect the engine from fiberglass dust and debris during
construction and clean‑up.

 

[rcknecht]

Seems to me that the recommendation for full synthetic have more to do with mercury's bottom line than engine longevity...

 

[hack4alivin]

Someone has way too much time on their hands!

You know other things to consider when comparing “today’s engines” verses “yesterdays engines” is the new technology going into the manufacture of said engines. Today’s engines are manufactured too much higher tolerance levels and are controlled and protected by computer systems. I know in my own case the engine computer has limited my power when a problem was detected long before any damage could be done…..

Just something else to consider, BTW… I have been using full synthetic oil in my engines.

 

[Still LauCo]

Good discussion.

My car requires synthetic (Mobil 1) oil, and that's what it gets. I will tell you that in Michigan, starting up in the winter months, you can actually "hear" the difference at start up. I put synthetic in my cars and boats.

 

[sbw1]

I sold a 79 SR express cruiser with a small block 260 HP engine that had over 3000 hours on the Hobbs. The new owner put a lot more hours on it before it failed and he trashed the boat. I've never encountered and engine problem and we use our boats for 7-10 years. Never changed oil in the cars at 3,000 miles either. We go with what is recommended and never had a problem with that practice either. My current Acura does not even have a recommended number of miles. A computer figures out when the oil needs to be changed. The oil service light usually comes on around 10,000 miles and I take it in. Lot's of old wives tales out there regarding oil changes. My Acura dealer routinely puts a sticker on my window which says to bring the car back in 3,000 miles. I throw that away.

 

[Pietro]

I sold a 79 SR express cruiser with a small block 260 HP engine that had over 3000 hours on the Hobbs. The new owner put a lot more hours on it before it failed and he trashed the boat. I've never encountered and engine problem and we use our boats for 7-10 years. Never changed oil in the cars at 3,000 miles either. We go with what is recommended and never had a problem with that practice either. My current Acura does not even have a recommended number of miles. A computer figures out when the oil needs to be changed. The oil service light usually comes on around 10,000 miles and I take it in. Lot's of old wives tales out there regarding oil changes. My Acura dealer routinely puts a sticker on my window which says to bring the car back in 3,000 miles. I throw that away.

OT: I just hate the new Acura/Honda system… On my TSX (called Accord in Europe) it keeps telling me to do service type A (includes oil) or B. This means I going to the dealer every 3,000-4,000 miles!!! :smt021
On the old one I just had service and oil change every 12,500 miles and everything was fine and simple!

 

[sbw1]

Hmm...wonder what's going on with that??

 

[skolbe]

BMW has their cars coming in at 16,000 miles for oil changes, the computer adjust for driving conditions.

 

[Dick Whetstone]

I think the VAST majority of marine engine failures are due to "things" other than oil issues. That being said, I am the proud second owner of an immaculate, original in every respect, 17 foot Glassmaster 1964 runabout with a 110 HP 153 CI Mercruiser stern drive.

This Mercruiser is so old that it is painted factory white, not black. The stern drive does not have hydraulic trim and tilt. When beaching or trailering you have to reach over the stern and manually lift the stern drive up (H-E-A-V-Y) and secure it with a factory supplied steel bracket.

It is anybody's guess how many hours this engine / stern dirve has run. If the boat was used an average of 50 hours a year for the past 46 years, that would be 2300 hours.

The engine and stern drive are both original. All that has ever been done are tune ups, hose and belt replacement, oil and filter changes, and annual stern drive oil and impeller changes. The engine uses NO oil and it still purrs. I don't even think the valve cover has ever been off.

The oil is, and has always been, Havoline 30W.

 

[OldSkool]

I'm old school in this, oils cheap.
Auto's 3000 miles 15-40wt , Boat in the fall when I winterize or 150 hours 15-40wt . I use a quality non syntheyic oil and never had any oil related failures.

 

[douglee25]

This discussion is fine and dandy but......

Over the last decade of changing my own oil in everything I own with a engine, all of which I use full synthetic oils, and changing oil for others, who do not, I've noticed some things.

The oil in my vehicles still feels "new" when I change them (7500 miles for my land based engines) It is super slick to the touch, a lighter color, and has a silky feel to it. By comparison, Dino-oil that my friends use, comes out like black tar, doesn't feel slick, and even on some, has a slightly gritty feel to it.

You can't tell me that Dino Oil is the same as Synthetic, because my personal experience tells me different. The proof is in the eyes and touch, (haven't tried the taste test, but I bet the synthetic oil would win there too.)

I'll stick with Synthetic oils.

How does one compare synthetic vs. dino by feel? By their very nature, synthetic oils have a lower coefficient of friction over dino oils. On the subject of dino oils, 'black' color means nothing about the useful life of the oil or how 'dirty' it is. This is a common misconception. Some oils turn blacker than others over a given period of time. Oil can turn black within the first few hours of running after an oil change. Again, the color of the oil is really meaningless. The only way to really tell an oil's contamination level or the lubricating value is by performing an oil analysis.

I personally worked closely with a petroleum engineer when designing and spec'ing out oil/grease for various pieces of equipment in the past. I brought up this very same topic to him regarding synthetic vs. dino oil. He concurred with some of the earlier posts that using a quality dino oil while performing routine oil changes will provide more than ample protection/longevity for your engine.

Doug