differences in preferred oil weights.

[Vortec376]

Originally Posted By: Merkava_4
5W-20 is a Dodge/Ford thing. GM still uses 5W-30. GM knows better.




GM's new Ecotec V8's will reguire 5W20 Oil...

 

[Swissdieselfan]

I think it is well documented that most new engines have similar wear rates with any oil between a 20 and 40 grade. The dispute is not about engine wear unless your vehicle is in a very hot desert and pulling heavy loads, it's about how often to change oil, oil consumption and even oil leak rates for older engines.

The EU auto R&D folks nearly all think that most non hybrids should use top quality full synthetic 0 or 5/30's when new and 0 or 5/40's when oldish.
The real main block risk factor is probably going to be from cheap 5/20's rather than full synthetic 0/20's for vehicles operated in a hot and hard environment where the owners sometimes forget to change the oil often enough, which might well be a case of using the old 3K mile OCI again. The Iffy and Eazy lube shops are all real keen on the 20 grades for obvious reasons, so it's not just a CAFE related game.

 

[Ducman]

Yep, fuel consumption is the big reason for the move to thinner oils in the US.
The CAFE regulations are driving the industry in that direction.
The Europeans are dealing with the polution issues from a different angle of attack.

IMO if it weren't for the modern higher quality group III type oils (or better), which are now available. We wouldn't be having this discussion.

Cheers

 

[Clevy]

K. I gotta ask. Where are all these engines that are failing faster using thinner oil. I'm a thicker is better guy,so don't go thinking I'm the thin police,I'm just wondering that's all.
I used to be 100% on board that thin oils were going to lead to engines dissolving in short order but that just doesn't seem to be the case at all.
In fact my hemi is the first engine I even bought a 20 grade for. My mod motors got a 40 grade. And the dodge is about to turn 280000 and it consumes no oil whatsoever between oil changes,nor does it seem to be wearing out at all.
Driving conditions in Europe are different. If I could drive my mustangs wot for hours at a time I might consider a thicker grade but 70mph is only spinning my engines at 2000rpm tops,so I can't justify thicker.
And if we get a mileage bump using a thinner grade,and engines last just as long,or longer which seems to be the case today,then why are we even having this discussion. Again.

 

[shDK]

But are there other reasons beside lowering fuelconsumption? Like the use of the car. Ones drove with with a collegue from the us who was moved over 2 month before. We drove from Denmark to ulm i southern germamy. And he was pretty amased and a few times a bit nervous on the trip simply because og the speed people where going. Especially down thrue germany. Can higher operating speeds be a reason ?

 

[Swissdieselfan]

Originally Posted By: shDK
But are there other reasons beside lowering fuelconsumption? Like the use of the car. Ones drove with with a collegue from the us who was moved over 2 month before. We drove from Denmark to ulm i southern germamy. And he was pretty amased and a few times a bit nervous on the trip simply because og the speed people where going. Especially down thrue germany. Can higher operating speeds be a reason ?



No it's the Green party in Germany who push real hard to reduce oil leaks and engine oil waste. The move from 5/30 to 5/40 for older cars was partly the result of leaky VW TDI's running out of oil after a good full power session on the autobahn, as that resulted in most lube shops erring on the heavy side in terms of what is listed in their oil guides.
At present the German auto sector are just sticking to using the best oils for the job, not for fuel economy, although they have moved slightly lower in terms of some auto box oils to reduce fuel consumption figures.

One point about modern engines, is that if you use an oil that is too thin, the engine won't fail like old ones did, a valve won't drop or a bearing won't fall apart, they just start burning and leaking oil. Even when the rings start to break up they still run, so most owners scrap them because of leaks, high oil consumption, smoke or emissions tests failures, assuming they don't just run out of oil first.

 

[CATERHAM]

Originally Posted By: shDK
But are there other reasons beside lowering fuelconsumption? Like the use of the car. Ones drove with with a collegue from the us who was moved over 2 month before. We drove from Denmark to ulm i southern germamy. And he was pretty amased and a few times a bit nervous on the trip simply because og the speed people where going. Especially down thrue germany. Can higher operating speeds be a reason ?

I've been using 20wt oil now for years in my European cars.
The reason I do is better overall driveability when the engines are cold, not just in the winter months but also during the warming up period in the summer months.
The key to doing so, is to make sure the oil is not too thin when your engine oil is fully hot. To determine that with certainty you need an oil pressure gauge. What you'll find is that for most uses the viscosity safety margin the manufacturers factor in is very large indeed to cover all possibilities such low quality shear prone oil, fuel dilution, poor maintenance practices and unexpectedly high oil temp's.
With an OP gauge you can monitor the oil's viscosity for yourself so that you don't need to run such a unnecessarily large viscosity safety margin and therefore benefit from a more optimized operational viscosity.

 

[147_Grain]

Originally Posted By: CATERHAM
The key ... is to make sure the oil is not too thin when your engine oil is fully hot.



Have also been a thicker 30-weight oil guy too.

CATERHAM and others have swayed me into blending my own viscosity to come-up with a 0W-25 or 5W-25 synthetic that gives the best of both worlds.

 

[CATERHAM]

Originally Posted By: 147_Grain
Originally Posted By: CATERHAM
The key ... is to make sure the oil is not too thin when your engine oil is fully hot.



Have also been a thicker 30-weight oil guy too.

CATERHAM and others have swayed me into blending my own viscosity to come-up with a 0W-25 or 5W-25 synthetic that gives the best of both worlds.

A SAE grade covers a range of viscosities and of course there is no such thing as a 0W-25 or 5W-25 grade.
Blending a 20wt and a 30wt oil will produce either a heavy 20wt or a light 30wt depending upon the final KV100 and HTHSV of the final oil.

 

[Swissdieselfan]

Originally Posted By: demarpaint
I feel a thick vs. thin war brewing.

I'll watch this time.


Stand up and be counted!!

The thick vs thin dispute is an American auto industry civil war only, the Japanese have always commited suicide with their cars and the folks in the rest of the world just use the best oil for the job AND get the best long engine life advice from their car stealers.

 

[CATERHAM]

Originally Posted By: Swissdieselfan

The thick vs thin dispute is an American auto industry civil war only, the Japanese have always commited suicide with their cars and the folks in the rest of the world just use the best oil for the job AND get the best long engine life advice from their car stealers.

There is no thick vs thin dispute within the American auto industy just with some old school advocates.

How have the Japanese commited suicide?

And "folks in the rest of the world", presumably Europe, use heavier oil grades because they always have and no one likes change (even for the better) unless it's forced upon them.

 

[Clevy]

Originally Posted By: CATERHAM
Originally Posted By: Swissdieselfan

The thick vs thin dispute is an American auto industry civil war only, the Japanese have always commited suicide with their cars and the folks in the rest of the world just use the best oil for the job AND get the best long engine life advice from their car stealers.

There is no thick vs thin dispute within the American auto industy just with some old school advocates.

How have the Japanese commited suicide?

And "folks in the rest of the world", presumably Europe, use heavier oil grades because they always have and no one likes change (even for the better) unless it's forced upon them.


That sounds like the closest to truth to me.

 

[tig1]

I used 20wt oils in the 60s and 70s when CAFE was a place to eat. I started using M1 5-20 in 1978 in an engine calling for 10-40. It's my understanding that lighter oils are easier on the oil pump, creates a little less oil temp, and flows faster in cold temps, and produces less engine wear on every start up. Euro is behind with their thicker is better idea IMO.

 

[RobertISaar]

it's a tradeoff between pressure when hot and flow at all times. if your pump runs up to the bypass pressure, you're losing flow. this will generally only happen when the oil is cold or at high RPMs. a thinner oil will create less pressure(since pressure is simply a measurement of resistance), meaning more can flow before it starts getting bypassed.

at least, those are my observations. unless i have issues that are directly caused by low pressure when hot, i tend not to move towards a thicker oil.

 

[tig1]

I guess the question has to be ask. Are there any cases of engines failing or wearing out before their time in the last 12 years, since Ford and some of the Asian engine builders have gone to 20Wt oils? None that I have heard of.

 

[Shannow]

Originally Posted By: tig1
I guess the question has to be ask. Are there any cases of engines failing or wearing out before their time in the last 12 years, since Ford and some of the Asian engine builders have gone to 20Wt oils? None that I have heard of.


Show me a single case of an engine failing or wearing out before it's time with 30s, 40s, 50s ?

While doing so, please refute that thicker oils increase the margin of asperite contact...

 

[astronomy]

Originally Posted By: Gabe
Originally Posted By: shDK
wrote that most engines calling for 0-20 was for 5-30 a couple of years ago, but suddenly changed when fuel consumption got more important.


I just assumed the specifications were updated for modern motor oils. A 30 wt from 10 years ago would drain out thinner than a modern 20 wt after a similar service. In other words, the engineers intended the motor to run on a specific viscosity - which is now achieved by a lighter grade.



So what do you folks think of Gabe's comment? If that's really the case, it would sway me towards using xW-20 in my 2000 Ford which was back specced from 5W-30. I'm chasing MPG as well as long engine life.

 

[tig1]

Originally Posted By: Shannow
Originally Posted By: tig1
I guess the question has to be ask. Are there any cases of engines failing or wearing out before their time in the last 12 years, since Ford and some of the Asian engine builders have gone to 20Wt oils? None that I have heard of.


Show me a single case of an engine failing or wearing out before it's time with 30s, 40s, 50s ?

While doing so, please refute that thicker oils increase the margin of asperite contact...


You ask the wrong question for this thread. No one has sugested that thicker oils produce shorter engine life. However many thick headed, oops,(LOL) I mean thicker oil guys do ring their hands over 20wt oils all the time.

 

[147_Grain]

Originally Posted By: RobertISaar
It's a tradeoff between pressure when hot and flow at all times.


This is where the Caterham Blend excels, as the thinner TGMO (Mobil) 0W-20 provides better "flow" at start-up and the 0W-40 ensures adequate oil "pressure when hot".

This Blend can be fine-tuned a bit and has the ability to have a 10% +/- thinner viscosity when cold and be almost 10% thicker when hot.

 

[Giorgiz]

I'm raising the question if I can put in my Mercedes Kompressor an oil thinner than 3.5 HTHS recommended by the specific mb.