Who here runs heavier motor oil?

[n16ht5]

hmm ill go 10-40 next oil change the same as my truck

i do a lot of hard driving. i dont get the advantage of light oil anyway.. ???

[friendly_jacek]

just my opinion,5-30 makes sense in cold climates,oil flows easier less engine damage at start-up.but hot weather oil--bullcrap--your engine runs the same temperature[or should] whether its 100 degrees outside or 30 degrees outside,so if anybody can explain why the same motor at the same temp needs heavier oil please explain.i understand "loose" engines can benefit from a thicker cushion of oil. but heavy oil will decrease milage whether you know it or not. ed

 

I don't know why it is so hard to understand that the oil tem is not the same as coolant temp. Oil is heated by the pistons/cylinders (150C) and cooled by air at the bottom of sump (well, ambient temp). The net oil temp is somewhere in between, compounded that it takes at least 20-30 mins or 10-15 miles to reach the equilibrium temp. So, short trip, or city driving (90% of US cars) benefits from 5W30. Long distance, high speed (think autoban), high load or towing require 10W40 or heavier oil. That explains why heavier oils are recommended outside US.

 

Look at you service and decide what you need. Unfortunately, customers in US get the dumbed-down, blanket advice: use only 5W30 (wonder why?).

 

I use synth 5W40 in summers for a third year, since I do some towing with my 00 legacy. Can't say that I saw a significant difference in MPG compared with 5W30 (MPG sucks all the time). Thing is, that heavier oils give you more friction at the piston level but less at the valvetrain. These effects can almost even out for some engines.

 

Boxers can indeed benefit from heavier oils because there is no need to have thinner oil to be able to pump it to the valve areas at the top of engine like you have in inline or V engines. Also, with solid lifters, you want to minimize the cam/lifter wear by using heavier lubricants and with healthy dose of Zn/P antiwear additives, like in API:SL/CI-4 rated HDEOs. ACEA:A3 rated oils are also good.

 

Please feel free to disagree.

[tunered]

transmission fluid is more of a coolant than a lubricant,thin oil carries away more heat[because of faster runoff]than heavy-thick oils.nascar qualify on 0-10 weight,drag racers race with 0 weight oil [consistancy of water] only 25 dollars a quart.so im not really convinced that heavier oil is any better.opinions is like a 0-0-0-0-0-0sbut there has to be something to this thin oils. ed

[1 Lucky Texan]

I suspect that when my cars sit in the summer sun here in Texas it would be quite easy for under-cowl temperatures to reach 140-160 F . At those temps for a coupla hours, what amount of 30W versus 40W oil is not squished out from the cam lobes? What about the oil squirters spraying oil directly on the underside of the pistons in the turbo engines? What about shutting the engine off after a hard run and the water stops circulating? What temp spikes can the valvetrain see? How much oil will be on the cam lobes the NEXT time the engine is started? If I could get Mobil 1 10W-40 at the same great price I always find the 10W-30 I'd run it. I may switch from 10-30 to the 10-40 after I get few thousand more miles.

 

I dunno

[friendly_jacek]

transmission fluid is more of a coolant than a lubricant,thin oil carries away more heat[because of faster runoff]than heavy-thick oils.nascar qualify on 0-10 weight,drag racers race with 0 weight oil [consistancy of water] only 25 dollars a quart.so im not really convinced that heavier oil is any better.opinions is like a 0-0-0-0-0-0sbut there has to be something to this thin oils. ed

 

Dude, don't you know that they tear down the engines after every race?

Racing is all about max output and not about max life!

[tunered]

dude, if they could buy better oil they would. ed

[tunered]

by the way dude,99 percent of car makers recomend 5w30or 10w30 do you think they have tested this or are smarter than them? heavier oil creates more pressure ,know why? because the oil pump has a hard time pushing this thick oil,there fore more pressure.too thick of a oil will actually starve the main and rod bearings.modern oils aint your old 3&1 oil anymore. ed

[tunered]

want to try a little test? take some of your motor oil and put it in a old kettle and put it on the stove,time it till its all burnt up,put 5w30 mobil one in a kettleand heat it -watch the time.you will have enough time to run to wallmart and get some. ed

[Snowman]

Some folks prefer light oil, others prefer heavier oil. It's just a preference ...use what you feel comfortable with.

 

At steady highway cruise in really cold winter air can result in as much as 30*F lower sump temp than the same steady cruise in a high summer temp situation. That's equivalent to jump in one SAE grade.

 

Depending on the outside temp, it can make more of a difference than that. Last year while driving 65 or so in -20 to -30 degree weather, I stopped for gas, checked the oil, and I was able to wipe the dipstick clean with my fingers...didn't feel hot at all.

[Setright]

I will avoid getting into the present debate, but would like to clarify what those numbers on the oil bottles mean:

 

"5W-30"

 

The 5W refers to the low temperature "pumpability", how cold can the oil be before turning "solid". It doesn't mean that the oil has an SAE grade 5 at a specific low temperature. The oil is much thicker at low temps. These oils ALL thin out as temperature increases.

 

The 30 is the SAE grade of viscosity at 100 degrees centigrade.

 

 

BOTH of these numbers are classifications and are based on ranges of values. This means that two oils with 5W-30 on the label can have different viscosities. They just fall under the same category.

 

So, I recommend reading the tech data sheets if you are serious about selecting oils. A slap avoiding oil will measure 100-130 Centistokes at 40 degrees C.

[99obw]

Try a 15W-40 HDEO Fleet oil like Delvac 1300.

 

Blitz nailed it. Warm climate a 15w-40 deezul earl would be best. Cheap, easy to find and robust. If you make a lot of short trips a 5w-40 will probably reduce wear and improve fuel economy.

 

I currently use 5w-40 HDEO in all vehicles in the summer, the diesel will be parked during winter, and the gassers get 0w-30 in the winter. Subject to change without notice. :-p

 

 

Some folks refer to it (erroneously) as DEEZUL AHWL. :-\

 

Oh, you mean like Mobil!?

 

"Mobil Delvac 1300 Super 10W-30 and 15W-40 are extra high performance diesel engine oils that help extend engine life in the most severe on and off highway applications."

 

http://www.mobildelvac.com/USA-English/Lubes/PDS/NAUSE2CVLMOMobil_Delvac_1300_Super.asp

[Setright]

Well folks, I have just drained my 6k mile old M1 5W-50 and refilled with M1 5W-30 for the winter.

 

I'll be back with feedback, rest assured.

[zyewdall]

by the way dude,99 percent of car makers recomend 5w30or 10w30 do you think they have tested this or are smarter than them? heavier oil creates more pressure ,know why? because the oil pump has a hard time pushing this thick oil,there fore more pressure.too thick of a oil will actually starve the main and rod bearings.modern oils aint your old 3&1 oil anymore. ed

 

I disagree that the manufacturer necessarily recommends the best oil. An engine with 200k miles on it is not the same as one straight from the assembly line. Clearances are all worn a bit more, and what may have been the best oil when new, isn't necessarily still the best oil. If the manufacturer had a graduated chart of what oil to use based on how many miles were on the engine (or better yet, what the particular bearing clearances were), then I'd go with their recommendations, but I think as engines get older, we're sort of on our own to determine what's best.

 

Zeke

[FirstSubaruGLwagon]

I run 20-W50 mainly because, It helps slow the leaks and it helps engine noise and most of the time the weather here is on the warmer side. Plus, Castoil GT 20w-50 seems to stay cleaner longer

[blitz]

Oh, you mean like Mobil!?

 

"Mobil Delvac 1300 Super 10W-30 and 15W-40 are extra high performance diesel engine oils that help extend engine life in the most severe on and off highway applications."

 

http://www.mobildelvac.com/USA-English/Lubes/PDS/NAUSE2CVLMOMobil_Delvac_1300_Super.asp

2nd paragraph:

 

"Mobil Delvac 1300 Super 10W-30 and 15W-40 also meet the API SL specification for gasoline engines and mixed fleets."

 

For obvious reasons, the marketing dept feels it's important to have the "Tough Truck" rhetoric separate & up-front.

[A DOG]

My XT6 slaps when its cold and sometimes whenever it wants. I use 10W-30. Should I be using something different?

[99obw]

2nd paragraph:

 

"Mobil Delvac 1300 Super 10W-30 and 15W-40 also meet the API SL specification for gasoline engines and mixed fleets."

 

For obvious reasons, the marketing dept feels it's important to have the "Tough Truck" rhetoric separate & up-front.

 

I don't disagree, I just wanted to point out that calling HDEO's diesel oils isn't necessarily incorrect, though perhaps incomplete. IMHO HDEO's are formulated primarily for diesels, operation in gassers being secondary. Those high ash levels are going to make for a tough life for a cat in an oil-burning gasser. I wonder if the HDEO's will be reformulated to meet API SM, or just say the heck with it and stick with the current certifications.

[friendly_jacek]

I don't disagree, I just wanted to point out that calling HDEO's diesel oils isn't necessarily incorrect, though perhaps incomplete. IMHO HDEO's are formulated primarily for diesels, operation in gassers being secondary. Those high ash levels are going to make for a tough life for a cat in an oil-burning gasser. I wonder if the HDEO's will be reformulated to meet API SM, or just say the heck with it and stick with the current certifications.

 

Yes, this is the usual criticism for the HDEOs. However, you can make an argument that if you have an oil burning engine, it will burn more say 5W30 oil than the 15W40 oil. The Phosphorus content (cat poison) in light duty oils is roughly 900 ppm for SL oils and 700 ppm in SM oils vs. 1200 ppm in current delvac/delo/rotella oils. The difference in the volume of the burnt oil will easily offset the increased concentration and cat may see more P with light duty engine oils. Furthermore, the increased levels of detergents in HDEO (twice the gas oils) will likely unstuck the rings and decrease consumption even further. It's a win-win situation. The only problem with HDEO is decreased MPG in light duty service when oil does not reach the nominal temp (again, city driving, short trips, cold climate).

[1 Lucky Texan]

I disagree that the manufacturer necessarily recommends the best oil. An engine with 200k miles on it is not the same as one straight from the assembly line. Clearances are all worn a bit more, and what may have been the best oil when new, isn't necessarily still the best oil. If the manufacturer had a graduated chart of what oil to use based on how many miles were on the engine (or better yet, what the particular bearing clearances were), then I'd go with their recommendations, but I think as engines get older, we're sort of on our own to determine what's best.

 

Zeke

 

Additionally here in the States, a manufacturer has a much greater incentive to recommend lighter weight oils to help meet CAFE standards, and I suspect they do that even if it means your engine may 'only' last 150K instead of 250K miles.

 

I dunno

[blitz]

I don't disagree, I just wanted to point out that calling HDEO's diesel oils isn't necessarily incorrect, though perhaps incomplete.

Most oil manfs DO offer some diesel-only products which shouldn't be used in a gasser. That's why I like to make a point of calling the mixed-fleet lube "mixed-fleet lube".

 

IMHO HDEO's are formulated primarily for diesels, operation in gassers being secondary. Those high ash levels are going to make for a tough life for a cat in an oil-burning gasser. I wonder if the HDEO's will be reformulated to meet API SM, or just say the heck with it and stick with the current certifications.

Here's the sulphated ash levels in common Exxon/Mobil products:

 

M1 5W-30 - 1.0%

M1 10W-30 - 1.0%

M1 0W40 - 1.2%

M1 15W-50 - 1.3%

Delvac 1300 - 1.3%

M1 Truck & SUV - 1.35%

Delvac1 5W-40 - 1.35%

 

I'm not sure how large of a difference those numbers represent, but it doesn't seem like too large a disparity.

 

IIRC, it's the phosphorous content (via the ZDDP) that messes with the cat, but phosphorous levels of SL fleet-lubes are typical SL levels (800-850 ppm).

 

Unless you've got some massive oil-consumption, those numbers shouldn't be a problem. Most racing oil for gas engines has about double those levels.

[zyewdall]

Yes, this is the usual criticism for the HDEOs. However, you can make an argument that if you have an oil burning engine, it will burn more say 5W30 oil than the 15W40 oil. The Phosphorus content (cat poison) in light duty oils is roughly 900 ppm for SL oils and 700 ppm in SM oils vs. 1200 ppm in current delvac/delo/rotella oils. The difference in the volume of the burnt oil will easily offset the increased concentration and cat may see more P with light duty engine oils. Furthermore, the increased levels of detergents in HDEO (twice the gas oils) will likely unstuck the rings and decrease consumption even further. It's a win-win situation. The only problem with HDEO is decreased MPG in light duty service when oil does not reach the nominal temp (again, city driving, short trips, cold climate).

 

I wonder how adding cats to the diesels will affect the oil formulations? So far I don't know that any of the cat equipped diesels have made it to the US (I believe they have to wait till we have low sulfer diesel here or the cats will quickly die).

 

I actually had no idea that the diesel oils had higher phosphorous and detergents than the ones for gassers. I figured there was something to help with higher temps, and deal with the much higher soot accumulation, but wasn't sure what...

 

Zeke

[99obw]

I wonder how adding cats to the diesels will affect the oil formulations? So far I don't know that any of the cat equipped diesels have made it to the US (I believe they have to wait till we have low sulfer diesel here or the cats will quickly die).

 

I actually had no idea that the diesel oils had higher phosphorous and detergents than the ones for gassers. I figured there was something to help with higher temps, and deal with the much higher soot accumulation, but wasn't sure what...

 

Zeke

 

My '92 Jetta diesel has a cat from the factory, as do many diesels currently sold in the US.

 

EDIT: I don't however know how long the cat will live with the "smoke screw" turned up so far that I leave a cloud behind me each time I punch it off-boost.

[zyewdall]

My '92 Jetta diesel has a cat from the factory, as do many diesels currently sold in the US.

 

EDIT: I don't however know how long the cat will live with the "smoke screw" turned up so far that I leave a cloud behind me each time I punch it off-boost.

 

You're right. The eco-diesels had a cat starting in '91 or so. I was referring to some new pollution control device/system that the european diesels just started getting in the last year or two, that can't stand the high sulpher american diesel, that I also obviously can't remember the right name for..... Maybe it's the particulate filters that new Merc's have, but I thought I remembered something else...

 

Oh well, entropy 1, Zeke's memory 0.

 

You know that screw is set at the factory and never supposed to moved, right? I change mine all the time....

 

Z

[99obw]

You're right. The eco-diesels had a cat starting in '91 or so. I was referring to some new pollution control device/system that the european diesels just started getting in the last year or two, that can't stand the high sulpher american diesel, that I also obviously can't remember the right name for..... Maybe it's the particulate filters that new Merc's have, but I thought I remembered something else...

 

Oh well, entropy 1, Zeke's memory 0.

 

You know that screw is set at the factory and never supposed to moved, right? I change mine all the time....

 

Z

 

Dang that factory seal was hard to remove!