New Oil thread........Oh no!

While this subject "OIL" has been posted to death here, one more isn't gonna kill ya!

I have just one question, and hopefully only one answer!

Question: Why do I see oil sold at retailers selling almost exclusively 5-20, 5-30, 5-40, (the emphasis is on the 5) what happened to 10 and 15 weights?

I read a thread in another MB forum a while ago from an older mechanic saying that you should not put a 5 weight oil in older engines, that from his life's experience as a mechanic, an older engine will age faster using light oils.

After reading his reasons why, chiefly that bearings have more space between and light oils just don't lube as well in these cases, I hesitate to use any oils lower than 10, and even at that, I feel safer with 15 wt.

Any thoughts?

[Brian Carlton]

Where are you buying oil?

I recently bought some Shell 10W-30 for the Dodge van. Wanted to see if it would get some better mileage than 10W-40. It didn't.

[leathermang]

For years air cooled lawn mower manufacturers haver recommended straight 30wt oil... specifically warning against using 10-30 or whatever.... This is a severe situation and thus I took that to mean that the additives given oils to get those readings decreased the lubrication abilities...

Automobile manufacturers have been under pressure to get better ' fleet overall ' gas mileage.. " readings... there may have even been money penalties for not reaching certain ' goals' set by the government....

Usually a lighter oil will be less resistance and thus give a small increase in mileage overall...

However, that may leave you with your engine lasting a bit less time ... but no one is really collecting those comparison numbers... so the government is not upset to have the ' tradeoff ' hit the car owner in that fashion. Short sighted... but some officials are that way... now that " image is everything"...

It does make a difference in the winter some places with regards to getting your oil to bearings quickly.... and I have always been in favor of pre-oilers like the big truck rigs use... they are in it for the ' long haul' if you will pardon the pun...

I am down here in the Texas heat... I buy Delo400 in Straght 40 wt ( by the 5 gallon bucket ) and use it in my 240 and my 5600 ford diesel tractor. I could not do that in the winter if I were in a colder area...

[Habanero]

I agree with Leathermang's assessment. On newer vehicles, the car itself will rot into the ground long before added wear on the bearings has a chance to do any harm. Thus, lighter oils for better fuel economy make a little more sense.

I also sometimes think those numbers are a bit contrived anyway, as there is more to the lubricating properties of a fluid than just its viscosity.

I also concur with the above posters, and has been my assessment of such since as far back as 1986.

Lite oil can achieve greater fuel economy. I want my car to live longer!

[Habanero]

If you're referring to your diesel, 15-40 is pretty much the standard diesel viscosity. Some synthetics are available in 5-40, but the wear data for Mobil 1 shows it to be superior to 15-40 dino anyway. I would worry more about it being a C rated oil than what the viscosity is.

[DieselAddict]

You guys are not looking at all the issues. The first number (before the W) is the cold viscosity. You want that to be fairly low. The second number is the hot viscosity, you want that to be fairly high. A 5W-40 oil will have almost the same viscosity at operating temperature as a 15W-40 oil, but it will flow better at startup which is what you want. Cold starts are probably the #1 source of wear in most engines. That's why I also like to add some Lucas oil stabilizer to my synthetic 5W-40 which I believe further helps reduce wear on cold startups by making the oil a little more sticky. Now if you're talking about 0W-20 or 5W-20 oils, yeah those are bad for the engine though they increase the fuel economy a tiny bit. A 20W oil will flow like water at operating temperatures.

[Dervman]

Dieseladdict has hit the nail on the head. Most modern vehicle lubricants are 'Multigrade' exactly for the reasons he gave. Having a 5W-40 Oil may seem too "thin" because it is easier to pour, but it gives the same lubricating performance as a Straight 40W oil at operating temperatures. That is the whole point. You definitely don't want to use a Straight 5W oil in your Diesel but 5W-40 or 15W-50 are just fine, although of course you should look for those that are Diesel Rated because their additive package will better handle the soot contamination.

Too many people think a 'Thicker' oil will give better lubrication but that is certainly not the case at cold start-up which as Dieseladdict correctly pointed out is where most engine wear occurs.

[leathermang]

" Having a 5W-40 Oil ...... but it gives the same lubricating performance as a Straight 40W oil at operating temperatures. "

Now that is getting a liberal with the numbers....

[92497pmu]

Originally Posted by DieselAddict

You guys are not looking at all the issues. The first number (before the W) is the cold viscosity. You want that to be fairly low. The second number is the hot viscosity, you want that to be fairly high. A 5W-40 oil will have almost the same viscosity at operating temperature as a 15W-40 oil, but it will flow better at startup which is what you want. Cold starts are probably the #1 source of wear in most engines. That's why I also like to add some Lucas oil stabilizer to my synthetic 5W-40 which I believe further helps reduce wear on cold startups by making the oil a little more sticky. Now if you're talking about 0W-20 or 5W-20 oils, yeah those are bad for the engine though they increase the fuel economy a tiny bit. A 20W oil will flow like water at operating temperatures.

Diesel addict & others-

I became seriously concerned with oil additives after coming across this website...
http://www.bobistheoilguy.com/images/lucas/lucas.htm
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic&f=5&t=000207

As an engineer in a previous life, I have a lot of faith in the motor oil engineers and manufacturers with their recommendations and formulations for viscosity, antifoam, blah, blah, etc...
Maybe their product is not perfect, but check it regularly, analyze occassionally & change it often.

PMU, out

[DieselAddict]

I knew it would be just a matter of time the second I mentioned Lucas before someone would dig up this experiment. Yes I've read it and that was before I started using Lucas products. I've never seen any foaming in my oil. The only time I saw foaming was when I poured their PS fluid too quickly while doing a fluid change and it trapped some air underneath, causing it to foam initially after starting the engine. All was well after I let the fluid sit for a few minutes to let the air come out. You are supposed to pour PS fluid slowly while doing a fluid change with any fluid. I don't know if this experiment is legit, maybe it is, but maybe it's a scenario that doesn't exist in the automotive world and is not applicable. We don't know how fast those gears were spinning for example. Having said, I haven't tried Lucas in my differential so I don't know if it will foam there. What sold me over to Lucas was my observation of how smooth my diesels were starting cold with the Oil Stabilizer even with the old style glow plug relays. Before that they would stumble for some time after a cold start. This tells me Lucas does indeed improve lubrication, at least after a cold start, by making more of the oil stay in the engine instead of all of it draining into the oil pan. I can also see the Oil Stabilizer is so much more "greasy" than regular oil. It takes a lot of effort to wash it off your hands. But this should be good for the engine.

[Tiredofagasser]

What about Slick-50, Prolong etc..? Any one here use anything like that?

[buyabsellonebay]

Originally Posted by Tiredofagasser

What about Slick-50, Prolong etc..? Any one here use anything like that?

Yea, it gets cold here in the northeast. I have tried a few different oils in my 300d. Synthetics seem to give better cold weather starting then regular oil. My car wouldn't start below 18 degrees F. on regular oil. Without the bolck heater being plugged in. I tried Mobil-1 that got it starting at 12 degrees F. My company is a mobil distributor. So I know one thing, it's crap! Mobil one is ok but it won't last like they say it will. I tried a few others with similar results.

I have run Amsoil in all my 2-strokes for years. I scare the my fellow racers when I tell them I pre mix at 100-1. Turning 9000+ rpms, I have had my spark plugs so white, a 4-stroker would be concerned. Amsoil has never let me down.

So I thought that I would give Amsoil's synthetic 15/40 a try. So far it's great. I have gotten it started in the single digits with no block heater. My oil consumption is also down. For reliability reasons. I plug it in at 15 degrees, on a timer, overnight.

My list of oil priorities beginning with the most important oil issue down to the details.

1. Make sure that there is oil in the engine.
2. Change oil and filter frequently enough.
3. Choose a weight that is compatible with your climate. Charts can be found in most owners manuals and in many other places.
4. Choose the correct TYPE, such as a universal grade CI4 for diesels etc.
5. Brand. It needs to be a premium brand, but contrary to popular belief, there is not a DRASTIC difference in oil brands as long as they are the correct type and weight and a premium brand, not the store brand. I, like many people, have my favorite brands, but if I chose the same type and weight oil, there would not be much difference.

Point number 5 is the one for which I expect the most criticism and disagreement.

Have a great day,

[Brian Carlton]

Originally Posted by LarryBible

5. Brand. It needs to be a premium brand, but contrary to popular belief, there is not a DRASTIC difference in oil brands as long as they are the correct type and weight and a premium brand, not the store brand. I, like many people, have my favorite brands, but if I chose the same type and weight oil, there would not be much difference.

Point number 5 is the one for which I expect the most criticism and disagreement.

Yeah, well, Larry, what do you know?? (sound like anyone we know??)

I've often thought about the store brands. If an individual was religious about oil changes every 3K and used a store brand for all oil changes, I'd be curious if he would suffer any measurable engine wear as compared to Castrol or Valvoline or any other name brand that you might choose.

My gut feeling is that oil is basically oil and that the name brands have different, and greater, additive packages to allow the oil to perform it's job for a longer period. However, 3K is not a long period (for most typical driving conditions) and the store brands might do the same job.

...........not that I intend to test the theory, however.