Just to clarify,
I agree oil is the cars blood.
but 20/50 is a thicker oil, not a thin (like water ) oil. It has its place in certain vehicles but is too old spec and thick for most modern engines.
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I think . . . 20W is a grade you would associate with very warm ambient temperatures (think Mediterranean and warmer); the 50 bit is something normally associated with very high-performance engines (think motorbikes). So, altogether it is suitable for hot stuff.
For good information and advice:
www.carbibles.com/engineoil_bible.html
where this is said:
"For ages, good old 20W/50 was the oil to have. But as engines progressed and tolerances decreased, a lighter, thinner oil was required, especially when cold."
And it's lubrication when cold that matters a great deal, because 80% and more of engine wear occurs on cold start-up. That's one reason why I've fitted Kenlowe pre-heaters to two of my cars, both of which I intend to run for a further decade at least. A 10W, 5W or 0W oil will be more effective lubricating a cold engine than a 20W or 15W will be. And, of course, engines are cold on start-up at least once every single day.
At the Oil Bible site, there is also this:
" 'High mileage' oils.
More and more oil companies are coming out with 'high mileage' oils now, some recommended for engines with as few as 75,000 miles on them. So what is a 'high mileage' oil you ask? Well very generally speaking, these oils have two additives in them which are more suited to older engines. The first is normally a burnoff-inhibitor which helps prevent the oil from burning off if it gets past an engine seal into the combustion chamber. The second is a 'seal conditioner', the exact makeup of which I'm not sure of, but it's designed to soak into seals such as head- and rocker-cover gaskets and force them to expand. Thus if one of the seals is a bit leaky, the seal conditioner will attempt to minimise the leak.
I've not had experience of high mileage oils myself, but a few people who've e-mailed me have passed on various tales from it being the miracle cure to it making no difference at all. I think the general rule-of-thumb though should be 'if it 'aint broke, don't fix it.' Just because your engine has over 75,000 miles on it, doesn't automatically mean you need high mileage oil. Is the exhaust sooty or smokey? Are you noticing oil leaks? Is the engine consuming oil? If your engine is working fine, the exhaust is clean and you're not noticing any problems, my guess is that it doesn't need high-mileage oil."
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Good post roger jones but it does depend on what vehicle we are talking about before specifying too thin an oil !
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Couldn't agree more. Check the handbook. I'll be interested to find out which cars should have 20W/50 in our climate. If we believe in global warming, perhaps there will be more in future. After a bit of snow and frost this coming week, perhaps there will be fewer believers . . .
Although I'm a Mobil 1 user (except for Magnatec in a 2.8 Capri), I sometimes wonder whether fresh oil at regular intervals is far more important than the brand or the grade. And then someone will pop up and claim that used oil is more effective than fresh oil. Hence, we remain in the land of belief rather than scientific certainty (oops, probability).
As ever, I claim no technical expertise, but I hope the sources referred to will help others to whom they may be new.
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Roger
As a classic car owner cheap 20W50 every 3k is fairly standard.
I guess you are referring to this bit of scientific testing
www.swri.org/3pubs/IRD1999/03912699.htm
There is of course the oil for life (unscientific)
www.synlube.com/since1992.htm
If you assume that 80% of wear is in the start up period (SAE paper) and maybe unavoidable, the OCI is more dependant upon oil and additive life and keeping engine clean and free from deposits. Another SAE paper looks at wear and HTHS. To address these issues on wear a 0W40 or more shear stable 5W40 synthetic oil appeas to be an optimum choice and these types of oil are capable of long drain intervals, unlike a cheap perhaps group 1 mineral 20W50 used by classic car owners.
Oils have improved
www.imakenews.com/lng/e_article000346479.cfm?x=b11...w
If cost and hassle are not a factor 5-6k OCis with a good synthetic 5W40 probably would be ideal, but maybe a waste of resources.
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As a classic car owner cheap 20W50 every 3k is fairly standard.
I've always used cheap 20/50, changed at the first convenient opportunity after 3,000 miles, with a new filter at every other oil change.
It's worked in my Volvo (361,000 miles) and Triumph (208,000 miles), both still going strong and in everyday use.
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There is of course the oil for life (unscientific) www.synlube.com/since1992.htm
Hmmmmm!!
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in the end i put castrol high mileage in with filter change new plugs and air filter,running like a dream considering shes done 120,000
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Thanks for the good links, mgbV8. Yes, of course, classics, but how old, I wonder -- 1970s at least? I wonder which is the youngest vehicle to have 20W/50 recommended.
It's good to see Cliff Pope's high mileages, and not at all surprising that 3k changes have played their crucial part in making them possible. Just like the MB W126 300 SE that I drove with 370k on it -- sweet as a nut, no rebuild, high annual mileage and 6k oil changes on the dot.
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One word of advice: you might find the effect wears off towards the first 4,000 miles. At least it did on son's Fiesta. So we changed oil and filter again at 5k miles (GTX again) and the second fill seems to give slightly better results than the first. (oil consumption appears to have virtually ceased - or is that the winter cold?)
madf
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Re High Mileage oils
www.valvoline.com/pages/valvoline_news_display.asp...5
A Chrysler Group spokesperson was critical of high mileage engine oils. Vehicle manufacturers conduct their testing on new vehicles under controlled conditions. At Valvoline, we took apart high mileage engines, determined which problems were typical, and went to work addressing those problems with special additives. Our research was verified at both independent test facilities and at Valvoline's state-of-the-art engine and field-testing facility. The result was the first motor oil for cars with more than 75,000 miles and a motor oil that helps battle increased oil consumption and performance loss. We want to see consumers get the most out of their vehicle, regardless of its age.
Roger
I assume HTHS was the demise of 20W50 road oil spec when it was found that HTHS correlates better with wear values found in actual oil analysis and actual tear-down measurements . This relationship is not linear and flattens as one nears a 40 weight oil. Three Exxon Researchers found that a minimum HTHS of about 2.8 mPA.s was the minimum HTHS viscosity needed for normal wear, with the higher the HTHS being better for minimum wear. Probably survived 1970s well at least for MGs.
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cheers il keep that in mind
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