Engine Oil Summary.

[nitroman]

Well, I will include one other thing the article said. Oil Additives, which account for roughly 10% (I can't remember if the article said by mass -'weight' to most people- or volume) of the oil, cost far more than the oil itself. Additives are the sole true reason you pay more for premium oil. Anything else is marketing.

[kmckmc]

Hi,

Kmckmc: Shell 5W/40 - Castrol FORMULA RS 10W/50 - Mobile One 5W/50 - Selenia 10W/60 - Shell Ultra Helix 5W/40 - Fuchs Titan Super Syn 5W/50
================



I am in Taiwan. I have decided that I will only use MOBIL 1 5W-50 Rally Formula from now on. It is not expensive and approved by Lotus for Elan M100. It works for Taiwan's climate, even in hot and humid summer.

Cheers,

[L.G.]

Kmckmc,

Does Mobil have any particular advantages over Shell 5w-40?

L.G.

[kmckmc]

In Taiwan's hot climate, the Mobil 1 5w-50 provides a higher OIL PRESSURE GAUGE needle level. When I was using Shell's , the OIL GAUGE meter level was low, and I did not feel comfortable seeing the needle lying almost flat.

[tigerdog]

Despite reading this entire thread and the wiki, a few of us are still faced with a problem: many of the oils loved and recommended here are simply not available on the left side of the Atlantic. Specifically, Castrol Edge is only available in 5W-30 and 10W-30. The magic 10W-60 and even the more common 5W-40s aren't commonly available here. One exception is a German full-synthetic called "Lubro-Moly". The BMW boys drool all over the stuff and it's readily available in a 5W-40. Mobil 1 0W-40 can be had in a few places but I have the same experience as others here; the engine is noisier and the idle oil pressure is somewhat low for my comfort. So - anyone here have experience with the lubro-moly full synth or am I about to embark on an experiment?

[Elanlover]

Despite reading this entire thread and the wiki, a few of us are still faced with a problem: many of the oils loved and recommended here are simply not available on the left side of the Atlantic. Specifically, Castrol Edge is only available in 5W-30 and 10W-30. The magic 10W-60 and even the more common 5W-40s aren't commonly available here. One exception is a German full-synthetic called "Lubro-Moly". The BMW boys drool all over the stuff and it's readily available in a 5W-40. Mobil 1 0W-40 can be had in a few places but I have the same experience as others here; the engine is noisier and the idle oil pressure is somewhat low for my comfort. So - anyone here have experience with the lubro-moly full synth or am I about to embark on an experiment?

Doug, you can get Amsoil synthetic in the "right" weight. Have a look over their site. The Euro Synth 5W-40 works well for me although you probably don't need to go as low as 5 winter weight.

[nitroman]

I've just read a long article on oil. The recommendation is to pick a better oil, but don't change from the recommended viscosity.

A 5W30 oil has the viscosity of a 5 weight oil at 0 degrees Fahrenheit and that of a 30 weight oil at 212F. If you start using a different weight oil that oil's temperature may not rise above, say, 200F. As 212F is the magic number for any oil, oil at 200F is too cold to do its intended job. An oil temp gauge is needed to determine if you are overtaxing your oil. Synthetic oils are generally effective up to even 300F, a pretty scary temperature!

However, it is OK to mix oil weights so long as that oil is from the same manufacturer.

Remember though, an oil temp gauge is all-important if you want to zero in on the perfect viscosity to use.

One thing I've pointed out from first-hand observation which the article backed-up is that synthetic oils have a better contaminant cleaning package, and will remove sludge-buildup in old engines.

[tigerdog]

Changed out the Mobil 1 0W-40 for Lubro-Moly Synthoil High Tech 5W-40 this afternoon. Immediately, noticeably quieter valve and engine noise. If I recall, the original spec was 10W-30. Next recommendation was Mobil 1 5W-50, then finally Mobil 1 0W-40 (see service bulletins in the manual download section.) Lotus have upped the top-end recommendation while dropping the base viscosity from 10 to 5 to 0. To Nitroman's point, then, selecting 5W base viscosity is a compromise between the original and current recommendations; oil temp should fall in range. In my car, Mobil 1 0W-40 made the valve gear too darned noisy and the hot idle oil pressure was <25 PSI. 5W-40 seems the best compromise between startup pumpability and hot engine protection. Lubro-Moly is readily available at NAPA stores, too, since it seems in favor by many German manufacturers. BTW, they also sell 10W-60 full synth here in the US for track days. I'll update the thread when I do next year's oil change (<1300 miles in the last 12 months.)

[tweetdriver63]

So I'm trying to understand. I have Mobil 1 10W-30 in mine, and I'm bothered by some noise. I have to think about it more, cause sitting here late at night, I can't recall if it's when cold or hot. I think it's bugging me until the car warms up, and there's not really any noise at idle, but it comes on when revved. I'll take a look tomorrow and come back.

[Elanlover]

I've just read a long article on oil. The recommendation is to pick a better oil, but don't change from the recommended viscosity.

I have to say that I don't entirely agree with that. While I spent some time in the industry with Shell, I'm far from an expert. But, what I do know is that a LOT has to do with where you live. Here in Toronto, a 10w30 weight oil would work all year round but not be "ideal" for the winter. You'd want a lighter oil in the range of a 5w or even a 0w winter weight to reduce cold start friction damage. Its quite common for people in colder climates to change out their 10w30 summer oil for a 5w30 (or lighter) winter oil when the temperatures start to drop. I wouldn't trust a 10w30 oil in a car in Winnipeg, Manitoba in February when its -40C outside.

Down south, you'd never need to go to a 0w or even 5w weight oil. It just doesn't get cold enough to need it and you'd sarcifice the protection at the higher end since there aren't too many oils that give a spread of 40 or 50 (like a 0w40 oil). For example, if I was in Texas I'd be running 10W40 or thicker, especially in the summer and with a hotter running engine like ours.

Car manufacturers can't predict who will buy thier cars and where they will be driven. So, they recommend the weights that are best for their vehicles based on "average" conditions knowing that they will cover the majority of cars wherever they are. But, I've never met anyone who lives in Averagetown, USA yet. People should be adjusting their viscosity requirements based on where they live to obtain optimal protection. I can't imagine a 10w30 oil in a car driven in Cairo in July providing the best protection no matter what the manufacturer says. The recommended viscosity will provide good protection for about 75 -80% of environmental conditions. Engines running in conditions where temperatures are colder or hotter than "average" (don't ask me how you figure that out with anything other than intuition or the SAE references) should have their oil viscosity adjusted for optimal wear protection.

There's other things that need to be considered if you're trying to obtain perfection but outside temperature is one of the most important as it affects engine temps significantly AND we can't control it like we can coolant condition, fans, engine design, etc.

[tigerdog]

I've never met anyone who lives in Averagetown, USA yet.

*cough* ahem, yes you have... remember, I live in San Diego???
Seriously, thanks for the well-thought response. I wondered about the issue of viscosity deviation myself - intuitively, it didn't make much sense.

[Elanlover]

I think San Diego might be warmer than average in the summer even with the ocean breezes. I think San Fran would be about as consistently average as one can get (does it ever deviate from 75F there????? ). Where you are Doug, a nice 10w40 would be just fine. There's no need to go to a 60 weight oil even on the track. Its too thick for our engines even when running hot. I put 10w40 in my car because Toronto tends to get quite hot in the summer with temps reaching 90F and high humidity.

As for engine noise, that's a completely different issue. Engine oil is meant for one thing - to lubricate the moving parts and protect against friction wear. You don't solve noisey tappet issues by changing the engine oil viscosity. You solve it by having better tappets or a better oil distribution system. Sure, it "may" have an effect but that's not because the engine oil was designed to quiet engine noise. You may have put a lighter oil in so it sprays further and reaches further to lubricate noisey components, especially at start up when the engine is cold. But, the downside is that the lighter oil won't protect when the engine gets warmer. And you want maximum protection at two times. Cold starts and when running hot and full out.

[stevieg8571]

After reading the above posts I'm now having second thoughts about my next oil change (which will be done same time as the R/H driveshaft's changed)

I was going to use Mobil 1 15W 50 that I already have and a K&N filter but now think it may be too thick for British temps, especially as what little warm weather we had is about to finish. I could easily get some Mobil 1 10W 40 instead as I think this would be more suitable.

Any thoughts?

[nitroman]

On page 58 of the owner's manual Lotus specs 10W/30 for above -20C with alternative 15W/40, and 5W/30 for below -20C with alternative 5W/50.

I have a habit of keeping the owner manuals of all my old cars, and they each spec different weight oils depending on ambient temp.

After reading the above posts I'm now having second thoughts about my next oil change (which will be done same time as the R/H driveshaft's changed)

I was going to use Mobil 1 15W 50 that I already have and a K&N filter but now think it may be too thick for British temps, especially as what little warm weather we had is about to finish. I could easily get some Mobil 1 10W 40 instead as I think this would be more suitable.

Any thoughts?

[rip]

different weight oils

I've seen this phrase used a lot. If you want to inrease your oil's weight, stick some more in & gravity will have more to pull against

Fluid thickness is viscosity, not weight.

[Elanlover]

different weight oils

I've seen this phrase used a lot. If you want to inrease your oil's weight, stick some more in & gravity will have more to pull against

Fluid thickness is viscosity, not weight.

That's quite true but the industry "slang" when talking about motor oils is "weight". Viscosity is measured as per the below:

Viscosity is ordinarily expressed in terms of the time required for a st­andard quantity of the fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid. Since viscosity varies inversely with temperature, its value is meaningless unless accompanied by the temperature at which it is determined. With petroleum oils, viscosity is now commonly reported in centistokes (cSt), measured at either 40°C or 100 °C (ASTM Method D445 - Kinematic Viscosity).

­The centistoke rating is then converted into the SAE weight designation using their chart. When you buy a motor oil and see 10W40 on it those numbers are the SAE weight designations not the centistoke rating. Here's another thing to think about.

Oil viscosity only comes in one weight (there's that term again ) - whatever the viscosity was when it was made. In other words, oil is only one viscosity. Its the polymer additives that allow manufacturers to create a 10W40 oil. That's an oil that "acts" like a 10W when cold and a 40 when hot. Ideally you'd want an oil that has as small a spread as possible. If you could run a straight 30 in the car you would beacause it would have no additives and behave exactly as a perfect 30 weight should. Just because the additives let an oil "act" like a thinner or thicker oil doesn't mean it IS thinner or thicker. But, the additives help with cold starts and cold outside temps that a 30 might not be as good at while adding high temp protection that a 30 can deliver.

I wish I could remember if companies start with a 40 and use additives to get to the 10 weight, start with a 10 then use additives to get to a 40 or start somewhere in the middle first Could be some do it differently which would be good to know. If you lived in a hot climate then an oil based on 40 with additives to help at lower temps and cold starts would be ideal. In cold climates the opposite would be better.

[RayD]

If you could run a straight 30 in the car you would beacause it would have no additives and behave exactly as a perfect 30 weight should.

Blair, you would be able to .... SAE30 is the one you would associate with car engines, in normal conditions.

I wish I could remember if companies start with a 40

I imagine it is a 30 for the same reason as above.

Ray

[Elanlover]

If you could run a straight 30 in the car you would beacause it would have no additives and behave exactly as a perfect 30 weight should.

Blair, you would be able to .... SAE30 is the one you would associate with car engines, in normal conditions.

I wish I could remember if companies start with a 40

I imagine it is a 30 for the same reason as above.

Ray

Well, you "could" run a single weight oil in a car but I wouldn't. Even in San Fran. And that's for all the reasons mentioned above (cold starts, cold climates, etc.). That's why we have multi weight (or multigrade) oils for cars. Most single weight oils are used in industrial settigns for equipment, etc. that's run indoors where the climate is somewhat controlled (and also in non internal combustion engine applications) and some diesel applications.

I'm not sure about the SAE 30 starting point. There's only so mush a guy can remember after 25 years. But, I've a hunch that its the lower weight (the winter weight) number that's the starting point. The polymers are bunched up at colder temps so the oil flows quickly but expand when warmer "slowing" oil flow so it acts like a heavier oil would. Here's a pic I found that gives a good guide to what oils are good for a given ambient temperature.

saerates.jpg

Note that some temp ranges are suitable for single weight oils but only where the ambient temps don't vary much at all. Most people tend to leave their oil in for a while so the multigrade oils are good when you don't change your oil often - like 90% of the drivers out there. If you madwe a plan to change your oil every 3 months you'd probably be able to get away with a single weight oil for each season. I still wouldn't redcommend it thoutgh as there's no real benefit to doing it.

[tweetdriver63]

Interesting that only the SAE 40 goes to an ambient temperature above 86 degrees F. Here in Mississippi, the high temp is above that about 5 months out of the year. Also, why would the high-end ambient temp be the same for 10W30 and 10W40? I would have thought the 40 would be higher.

[nitroman]

Correct, an oil is made from a base stock equal to the lower of the two weights. The long-chain polymers (additives) expand as the oil-temp rises such that the oil, at 212F, flows like the higher viscosity number of the oil.

If you could run a straight 30 in the car you would I'm not sure about the SAE 30 starting point. There's only so mush a guy can remember after 25 years. But, I've a hunch that its the lower weight (the winter weight) number that's the starting point. The polymers are bunched up at colder temps so the oil flows quickly but expand when warmer "slowing" oil flow so it acts like a heavier oil would.