So I just checked with my Land Rover shop, and they've been putting nonsynthetic Valvoline 5W30 in my Disco. Never occurred to me to check with them before, assuming that they were using whatever was best for the the Disco since they're a Land Rover/Jag shop.

Thoughts on this? Should I switch to synthetic?

 

Yes, I would switch.

Geotrash-15w- is not much thicker when cold than a 10w-, only take less than a second longer to pump through the engine. My engine is hot longer than it is cold, therefore I prefer a heavier motor oil, for me it is the better choice.

Everybody has to decide which motor oil is best for them. My trk gets no less than 6 hours of idle time per week, day after day of stop and go driving, off roading all day in 95 degree heat with the A/C cranking away, long trips on the expressway, pulling stumps out of the ground, hauling fire wood, pulling a hay wagon while bailing hay, and never needing to add a single quart between oil changes. So for me Mobil 1 15w50 is the oil that I will use.
That's my 2 cents.

 

It's your truck, so by all means do as you wish. I didn't mean to tell you how you should do it. Just so long as others know that there is no rational reason to do the same (and in fact the science is against it) then it's all good.

Dave

 

Too bad Royal Purple does not make a 15w 50. That is why I just use their 15w 40.

 

Some good reading from an industry expert I found elsewhere regarding the aforementioned SM grade and additive issue.

Engine Oil Mythology

Myths are ill-founded beliefs held uncritically by interested groups. Over the years there has been an overabundance of engine oil myths. One was that the only good oils were oils made from “Pure Pennsylvania Crude Oil.� This one got started before the Second World War when engine oil was crude oil with very minimal refining, and crude oil from Pennsylvania made better engine oil than Texas or California crude. With modern refining, almost any crude can be made into good engine oil.

The next myth was that “modern� detergent engine oils were bad for older engines. This one got started after the Second World War, when the government no longer needed all the detergent oil for the war effort, and it hit the market as Heavy-Duty oil. These new detergent oils gave the pre-war cars, which had been driven way past their normal life and were full of sludge and deposits, a massive enema. In some cases bad things happened such as increased oil consumption – the piston rings were completely worn out and the massive piston deposits were the only thing standing between merely high and horrendous oil consumption. If detergent oils had been available to the public during the war, this myth never would have started.

Amazingly, there are still a few people today, 60 years later, who believe that they need to use non-detergent oil in their older cars. Apparently it takes about 75 years for an oil myth to die.

Then there is the myth that new engines will not break-in on synthetic oils. Apparently there was an aircraft engine manufacturer who once put out a bulletin to this effect. Clearly the thousands and thousands of cars filled with Mobil 1 as factory-fill, which have broken-in quite well, should have put this one to rest. However, this myth is only 40 years old, so it has another 35 years to live.

All of these myths have a common theme; newer oils are bad. And this brings us to the latest myth – new “Starburst�/ API SM engine oils are bad for older cars because the amount of anti-wear additive in them has been reduced. This one has gotten big play in the antique and collector car press lately. The anti-wear additive being discussed is zinc dithiophosphate (ZDP).

Before debunking this myth we need to look at the history of ZDP usage in engine oil.

ZDP has been used for over 60 years as an additive in engine oils to provide wear protection and oxidation stability. Unfortunately, ZDP contains phosphorus, and phosphorus is a poison for automotive catalysts. For this reason ZDP levels have been reduced by about 35% over the last 10-15 years down to a maximum of 0.08% for “Starburst�/API SM oils.

Zinc dithiophosphate was first added to engine oil to control copper/lead bearing corrosion. Starting in 1942, a Chevrolet Stovebolt engine with aftermarket copper/lead insert-bearing connecting rods was used for the standard engine oil qualification test. The insert-bearings were weighed before and after test to evaluate weight loss due to corrosion. The phosphorus levels of oils that passed the test were in the 0.03% range.

In the mid-1950’s, Oldsmobile got into a horsepower war between its Rocket engine and the Chrysler Hemi. Both companies went to high-lift camshafts and both got into camshaft scuffing and wear problems very fast. There were three solutions: 1) better camshaft and lifter metallurgy, 2) phosphating the camshaft, and 3) increasing the phosphorus level from ZDP up to the 0.08% range. In addition, the industry developed a battery of oil tests (“Sequences�), two of which were valve-train scuffing/wear tests.

Knowing that this higher level of ZDP was good for flat-tappet valve-train scuffing and wear, some oil companies, thinking that they were offering the customer additional protection dumped even more into the oil. It was soon learned, however, that, while going above about 0.14% phosphorus might decrease break-in scuffing, longer-term wear increased. Further, at about 0.20% phosphorus, the ZDP started attacking the grain boundaries in the iron, resulting in camshaft spalling.

In the 1970’s, the ZDP level was pushed up to the 0.10% phosphorus range because it was a cheap and effective antioxidant. The increased antioxidancy was needed to protect the oil in Cadillacs pulling Airstream trailers from thickening to a point where the engine could no longer pump it. Recently, the need for this higher level of ZDP to protect the oil from thickening has been greatly reduced with the introduction of modern ashless antioxidants that contain no phosphorus.

Enough history. Getting back to the myth that “Starburst/API SM oils are no good for older cars, the argument put forth by the myth believers is that while these oils work perfectly well in modern, gasoline engines equipped with roller camshafts, they will cause catastrophic wear in older engines equipped with flat-tappet camshafts.

The “Starburst�/API SM oil standards were developed by a group of OEM, oil additive company, and oil company experts. When developing any new engine oil standard, the issue of “backward compatibility� is always of great importance. Indeed, the group of experts spent a lot of time researching this issue. In addition, multiple oil and additive companies ran “no harm� tests on older cars with the new oils; no problems were uncovered.

Beyond the “no-harm� testing, the new “Starburst�/API SM specification contains two valve-train wear tests. One is the Sequence IVA, which tests for camshaft scuffing and wear using a 2.4L Nissan single overhead camshaft engine with slider finger followers. The wear limits for this test were tightened from those of the previous oil specification, even though the old spec had a higher, 0.10%, phosphorous limit. The second test is the Sequence IIIG, which evaluates cam and lifter wear. For this test, a current-production, GM Powertrain 3.8L engine with the valve train replaced with a flat-tappet system, similar to those used in the 1980’s, is used. The only reason for using this older valve-train design is to ensure that older engines are protected. All “Starburst�/API SM oil formulations must pass these two tests.

In addition to the protection offered by these two valve-train wear tests and the “no-harm� testing, a review of the knowledge gained over the years in developing previous categories also indicates that no problem should be expected. For example, the new “Starburst�/API SM oils contain about the same percentage of ZDP as the oils that solved the camshaft scuffing and wear issues back in the 1950’s. They do contain less ZDP than the oils that solved the oil thickening issues in the 1960’s, but that is because they now contain high levels of ashless antioxidants, which were not commercially available in the 1960’s.

The oil’s ZDP level is only one factor in determining the life of an older camshaft or a new aftermarket camshaft. Most of the anecdotal reports of camshaft failures attributed to the newer oils appear to be with aftermarket camshafts. Breaking in extremely aggressive aftermarket camshafts has always been a problem. The legendary Smokey Yunick wrote that his solution to the problem was to buy multiple camshafts and simply try them in a slave engine until he found one that survived break-in without scuffing.

Despite the pains taken in developing special flat-tappet camshaft wear tests that these new oils must pass and the fact that the ZDP level of these new oils is comparable to the level found necessary to protect flat-tappet camshafts in the past, there will still be those who want to believe the myth that “new oils will wear out older engines.� Like other myths before it, history teaches us that it will take about 75 years for

 

Cool, I'm flabergasted. Does this mean I'm not an alien anymore......Or are you one tooIf you re-read, you'll see that I wasn't grossier at all, and rather polite. 'Auriez-vous l'obligeance means' would you be so kind and 's.v.p' means s'il vous plait or please. This wording isn't the one I'd choose should I want to be rude. You might be a bit rusted, but I'm impressed none the less!!!


For those wondering what the heck we're talking about......I wrote in french that most of the 'normal' people here didn't understand anything about the mumbo jumbo he submitted and was asking him to be a bit clearer for us to actually benefit from his submitted info, saying that we couldn't understand a word of what he said, no more than he could read a word of what I wrote.....But the sun of a gun actually did get what I said, with the exception of the tone I said it with. And actually responded in french.....shooooosh..... I'm still impressed

 

I got the wording, but it was the fact that it was in francais that I perhaps misinterpreted. I felt a simple "could you please explain" in English would have been all that was necessary. Maybe I read too much into it. Anyway, I hope it is a little clearer and sorry if there was a misunderstanding.. I'm really not an a@@hole.

 

Hooly shoot, never even started thinking you were. Its all good!! Should you want to read more into things, try Discoweb.com There is the place to be royally told off.