GM's Active Fuel Managment Syatem

LBZ · Jan 21, 2017

dgiles said:
You don't need full synthetic to run higher km's.

The average hours on a vehicle at 10,000km is only 200 hours. Any major construction equipment runs 500hrs between changes with dino oil. Plus, our equipment runs min 15,000hrs - 20,000hrs before we start thinking of trading them off. 5000km oil changes is old thinking and a waste of $$ and resources.

I agree.
Stop and go driving with little to no highway travel is hard on engines and definitely increases oil contaminants and condensation but changing it too often can also be counterproductive as it can introduce contaminants as well as other side effects.

I don't know where people get 5000km from. For eons it has been 5000 miles which is about 8000km. If it was me I'd do it in the spring and fall to get rid of the condensation or 8000km for regular oil, 15000 for synthetic for mixed city/hwy driving. Or better yet, go by regular oil sampling to determine your optimum oil change interval.

From another site (and to note alot of what is stated was also mentioned in an oil analysis course I took a few years ago):
5000 km change intervals are harmful to your engine and our DI engines are even more vulnerable to the type of damage done by over servicing than PFI engines.

Why does the problem exist?
It's a cultural thing that arose in the US and was driven by marketing and profit making. The consequent myths and consumer expectations are now entrenched. The cultural gap is now so broad than in the US a car may have an 8000km OCI, while the same model, from the same production line, might have a 20,000 km OCI when sold in Europe where people aren't affected by the myths.

Why it's OK to follow the manufacturers service interval
All synthetic oils are capable of exceeding the manufacturers recommended OCI by at least 50% or more. It's incorrect to suggest the oil could break down or succumb to sludge any earlier.

People using oil analysis reports to justify over servicing aren't reading them correctly. None of the reports that I've seen on DISI engines have shown oil that has reached condemning limits in terms of insolubles and oxidation. As for the solubles, if they are excessive, you need to drive the car further, not change the oil.

The references to carbon contamination are also incorrect. People naturally assume that black oil is unhealthy, when the opposite is true. The colour of the oil is an indication of how well it's doing its job. The darker the better (up to a point not exceeding the manufacturers OCI).

If you had a problem with contamination (not that you do, but if you did) the solution is to change the oil filter, not the oil.

Why is it harmful to change the oil too frequently?

In a word; volatility. Oil volatility is at its greatest in the first 3000km after an oil change. After that the volatility reduces and the oil stabilises.

Volatility is particularly bad for a DI engine because all of the lost fractions exit via the PCV system. Much of it goes out through the rocker cover vent, into the intake, through the turbo compressor and intercooler, then puddles in the bottom of the inlet manifold where it combines with the stuff coming through the PCV valve to coat the inlet valves and combustion chambers in gunk.

That black soot you see in your exhaust pipes, don’t assume it’s all caused by rich mixture. Excessive oil changing will contribute more soot.

The presence of oil in the intake also lowers the octane rating of your fuel leading to detonation.

The NOACK volatility test quantifies the extent of oil evaporation. The test standard - ASTM D5800 - 08 Standard Test Method for Evaporation Loss of Lubricating Oils by the Noack Method – also hints at another kind of danger associated with frequent oil changes where it states “Procedure C, using the Selby-Noack apparatus, also permits collection of the volatile oil vapors for determination of their physical and chemical properties. Elemental analysis of the collected volatiles may be helpful in identifying components such as phosphorous, which has been linked to premature degradation of the emission system catalyst.”

A lot of phosphorous is lost in the initial boil-off phase of new oil and it’s likely to be harming oxygen sensors and cats.

Engine manufacturers understand the problem and it would be easy for them to identify the type of damage done by over servicing and potentially result in a warranty claim denial.

Summary
By changing your oil at 5000km, you are subjecting your engine to oil that is almost always in the initial boil-off phase. It's contaminating and filling your engine with gunk. Contrary to popular and uninformed opinion, oil that is 10,000 km old is not likely to be harmful, and would certainly be less harmful than fresh oil.

Cdnfireman · Jan 21, 2017

LBZ said:
I agree.
Stop and go driving with little to no highway travel is hard on engines and definitely increases oil contaminants and condensation but changing it too often can also be counterproductive as it can introduce contaminants as well as other side effects.

I don't know where people get 5000km from. For eons it has been 5000 miles which is about 8000km. If it was me I'd do it in the spring and fall to get rid of the condensation or 8000km for regular oil, 15000 for synthetic for mixed city/hwy driving. Or better yet, go by regular oil sampling to determine your optimum oil change interval.

From another site (and to note alot of what is stated was also mentioned in an oil analysis course I took a few years ago):
5000 km change intervals are harmful to your engine and our DI engines are even more vulnerable to the type of damage done by over servicing than PFI engines.

Why does the problem exist?
It's a cultural thing that arose in the US and was driven by marketing and profit making. The consequent myths and consumer expectations are now entrenched. The cultural gap is now so broad than in the US a car may have an 8000km OCI, while the same model, from the same production line, might have a 20,000 km OCI when sold in Europe where people aren't affected by the myths.

Why it's OK to follow the manufacturers service interval
All synthetic oils are capable of exceeding the manufacturers recommended OCI by at least 50% or more. It's incorrect to suggest the oil could break down or succumb to sludge any earlier.

People using oil analysis reports to justify over servicing aren't reading them correctly. None of the reports that I've seen on DISI engines have shown oil that has reached condemning limits in terms of insolubles and oxidation. As for the solubles, if they are excessive, you need to drive the car further, not change the oil.

The references to carbon contamination are also incorrect. People naturally assume that black oil is unhealthy, when the opposite is true. The colour of the oil is an indication of how well it's doing its job. The darker the better (up to a point not exceeding the manufacturers OCI).

If you had a problem with contamination (not that you do, but if you did) the solution is to change the oil filter, not the oil.

Why is it harmful to change the oil too frequently?

In a word; volatility. Oil volatility is at its greatest in the first 3000km after an oil change. After that the volatility reduces and the oil stabilises.

Volatility is particularly bad for a DI engine because all of the lost fractions exit via the PCV system. Much of it goes out through the rocker cover vent, into the intake, through the turbo compressor and intercooler, then puddles in the bottom of the inlet manifold where it combines with the stuff coming through the PCV valve to coat the inlet valves and combustion chambers in gunk.

That black soot you see in your exhaust pipes, don’t assume it’s all caused by rich mixture. Excessive oil changing will contribute more soot.

The presence of oil in the intake also lowers the octane rating of your fuel leading to detonation.

The NOACK volatility test quantifies the extent of oil evaporation. The test standard - ASTM D5800 - 08 Standard Test Method for Evaporation Loss of Lubricating Oils by the Noack Method – also hints at another kind of danger associated with frequent oil changes where it states “Procedure C, using the Selby-Noack apparatus, also permits collection of the volatile oil vapors for determination of their physical and chemical properties. Elemental analysis of the collected volatiles may be helpful in identifying components such as phosphorous, which has been linked to premature degradation of the emission system catalyst.”

A lot of phosphorous is lost in the initial boil-off phase of new oil and it’s likely to be harming oxygen sensors and cats.

Engine manufacturers understand the problem and it would be easy for them to identify the type of damage done by over servicing and potentially result in a warranty claim denial.

Summary
By changing your oil at 5000km, you are subjecting your engine to oil that is almost always in the initial boil-off phase. It's contaminating and filling your engine with gunk. Contrary to popular and uninformed opinion, oil that is 10,000 km old is not likely to be harmful, and would certainly be less harmful than fresh oil.

j

Just for clarification here:

Youre saying black, sooty oil is better for an engine than new clean oil? And that new oil in an engine will actually cause the engine too soot up more?

That new clean oil has constituent components that "boil off" at normal operating temperatures and actually contaminate the engine?

I agree reed that changing oil too often is a waste of money and resources, but I'm having a hard time believing a lot of what you have stated.

MK4TDI · Jan 21, 2017

Cdnfireman said:
j

Just for clarification here:

Youre saying black, sooty oil is better for an engine than new clean oil? And that new oil in an engine will actually cause the engine too soot up more?

That new clean oil has constituent components that "boil off" at normal operating temperatures and actually contaminate the engine?

I agree reed that changing oil too often is a waste of money and resources, but I'm having a hard time believing a lot of what you have stated.

In my diesel that I had for 11 years, I did 16,000 km drain intervals. That engine would turn the oil black in the first hour after an oil change.

In my new 5.3 DI gas pot, the oil will be dark after 2000km.

What he's trying to get across is that just because the oil is dark or black doesn't necessarily mean it's bad and time to change it.

And most people do have a hard time believing information that is posted, cause it is not the norm.

Sent from my HTC One M9 using Tapatalk

TJ(turbojoe) · Jan 21, 2017

dgiles said:
You don't need full synthetic to run higher km's.

The average hours on a vehicle at 10,000km is only 200 hours. Any major construction equipment runs 500hrs between changes with dino oil. Plus, our equipment runs min 15,000hrs - 20,000hrs before we start thinking of trading them off. 5000km oil changes is old thinking and a waste of $$ and resources.

I drove 155kms without any oil or a filter with my duramax diesel that I used full synthetic and changed every 35000kms /1500hrs and the truck has over 500 000kms now and runs just as it did from new. I also ran both by Harleys out of oil completely using full synthetic changing every 20 000kms. and they are also like new. I strongly believe synthetic is a must but not every 5000kms . And if you have used regular oil already and are having engine issues I would stick to regular oil.

Don't ask why I run everything out of oil. Lol . That's not the point here lol

Where is the Snow

LBZ · Jan 21, 2017

Cdnfireman said:
j

Just for clarification here:

Youre saying black, sooty oil is better for an engine than new clean oil? And that new oil in an engine will actually cause the engine too soot up more?

That new clean oil has constituent components that "boil off" at normal operating temperatures and actually contaminate the engine?

I agree reed that changing oil too often is a waste of money and resources, but I'm having a hard time believing a lot of what you have stated.

Well as I said it was a quote from another site, but summed up it mentions similar info I have heard at oil analysis seminars I have been too.

Bottom line is colour means nothing. As about 25% of the oil is made up of additives, and these are what breakdown first, and the oil is long turned black before this happens it really isn't a good guide to go by.

Some of the additives are there to remove varnish, rust, separate combustion gasses and moisture. The volatility of the oil being highest when it is new results in these contaminants being carried through the vapour that goes into the PCV and in turn gets spread throughout the engine instead of staying in the oil and/or being caught by the filter. My diesel has had the PCV rerouted to atmosphere instead of back into the engine and I for sure have much more blowby smoke when my oil is freshly changed than when it has a few thousand miles on it. This is the volatility.

So this and the fact that external contaminants are introduced more frequently the more often you change the oil are reasons over servicing can be worse than leaving it as per your oil change indicator or manufacturers recommended intervals.

FWIW I've worked for a couple companies that religiously sample all their oils as part of their pm programs and have found extending their intervals in the engine has resulted in cost savings in fewer oil changes, less component wear, and better running engines. The one company took a few trucks from the fleet (of which no trucks are assigned to drivers so all get abused equally), extended the intervals and this was their findings via sampling.

Take it as you will, this is what I've seen. I go 15k between changes in my diesel with synthetic with just a filter change around 8k. My ford leaks enough it just gets a filter every 6 months with no oil changes lol.

Cdnfireman · Jan 21, 2017

LBZ said:
Well as I said it was a quote from another site, but summed up it mentions similar info I have heard at oil analysis seminars I have been too.

Bottom line is colour means nothing. As about 25% of the oil is made up of additives, and these are what breakdown first, and the oil is long turned black before this happens it really isn't a good guide to go by.

Some of the additives are there to remove varnish, rust, separate combustion gasses and moisture. The volatility of the oil being highest when it is new results in these contaminants being carried through the vapour that goes into the PCV and in turn gets spread throughout the engine instead of staying in the oil and/or being caught by the filter. My diesel has had the PCV rerouted to atmosphere instead of back into the engine and I for sure have much more blowby smoke when my oil is freshly changed than when it has a few thousand miles on it. This is the volatility.

So this and the fact that external contaminants are introduced more frequently the more often you change the oil are reasons over servicing can be worse than leaving it as per your oil change indicator or manufacturers recommended intervals.

FWIW I've worked for a couple companies that religiously sample all their oils as part of their pm programs and have found extending their intervals in the engine has resulted in cost savings in fewer oil changes, less component wear, and better running engines. The one company took a few trucks from the fleet (of which no trucks are assigned to drivers so all get abused equally), extended the intervals and this was their findings via sampling.

Take it as you will, this is what I've seen. I go 15k between changes in my diesel with synthetic with just a filter change around 8k. My ford leaks enough it just gets a filter every 6 months with no oil changes lol.

I agree that just the colour of the oil is no indicator of oil condition. I don't agree however that the additive package is the component of the oil that breaks down quickly. It's the additives that make it a lubricating oil versus just a refined hydrocarbon. The additives ( viscosity improves, detergents, anti foamers, anti wear additives TBN modifiers etc) are the part of the package that protects the moving parts by creating a film strength that sticks to the moving parts, carries heat to the coolers and retains the byproducts of combustion in suspension until it gets to the filters.
The constituents in the additive package must have a higher boiling point than the normal operating temps otherwise they wouldn't last more than a few hours in the crank case. I agree that the additive package can lose its effectiveness over time, but it's due to dilution, shearing, acidification etc due to condensation and the byproducts of combustion. I don't agree that they " boil off".
I don't understand how external contaminants Can be introduced from an oil change if it's done properly. I agree that an oil sampling program can save costs in a fleet scenario with heavy trucks and equipment, although the less component wear comment is dubious unless you're tearing engines apart for comparison. Again, oil life in a large, high oil capacity constant temperature/speed engine is markedly different than an automotive engine.
I change my oil every 8K or six months, whatever occurs first, with oil sampling once a year on my diesel.
My theory is that the cheapest thing you can do to a vehicle is maintain it well.
What you're doing obviously works for you and to each his own.

tex78 · Jan 22, 2017

Cdnfireman said:
I agree that just the colour of the oil is no indicator of oil condition. I don't agree however that the additive package is the component of the oil that breaks down quickly. It's the additives that make it a lubricating oil versus just a refined hydrocarbon. The additives ( viscosity improves, detergents, anti foamers, anti wear additives TBN modifiers etc) are the part of the package that protects the moving parts by creating a film strength that sticks to the moving parts, carries heat to the coolers and retains the byproducts of combustion in suspension until it gets to the filters.
The constituents in the additive package must have a higher boiling point than the normal operating temps otherwise they wouldn't last more than a few hours in the crank case. I agree that the additive package can lose its effectiveness over time, but it's due to dilution, shearing, acidification etc due to condensation and the byproducts of combustion. I don't agree that they " boil off".
I don't understand how external contaminants Can be introduced from an oil change if it's done properly. I agree that an oil sampling program can save costs in a fleet scenario with heavy trucks and equipment, although the less component wear comment is dubious unless you're tearing engines apart for comparison. Again, oil life in a large, high oil capacity constant temperature/speed engine is markedly different than an automotive engine.
I change my oil every 8K or six months, whatever occurs first, with oil sampling once a year on my diesel.
My theory is that the cheapest thing you can do to a vehicle is maintain it well.
What you're doing obviously works for you and to each his own.

Like I said, oil is cheap, engines are not

My ag mechanic dad has done this forever, I have, and have switched lots of people to it

Funny thing is, in the hole list that I know of, no one has ever done a engine

Where lots of engines I.ve done for people not on that list...... Huh eh

sent while drinking tea's

LBZ · Jan 22, 2017

You guys can do what you want. If you want to waste money fine by me.

I'll believe what I've seen first hand and go with what I've learned from petrochemist's and people that have spent their careers studying and testing oils.

BTW, when an oil change for a diesel with synthetic oil is upwards of $150 to $200, and you actually drive it more than 5km a month, it's not that cheap. If I ran that program I'd spend $2500 a year on oil in my truck alone. Times 3 vehicles of which one of the other ones gets almost 50k a year ya an engine is cheaper.

Don't run cheap oil and you will have no issues running more than 3000 miles between changes.

j335 · Jan 24, 2017

For those conventional oil lovers have you guys ever done a freeze test on your oil? Reason #1 I run synthetic or semi synthetic. I did some tests back in the old university days, the extremely low cloud/freeze point for conventional is what changed my mind.
I buy oil on sale, surprising very reasonable for synthetic.

sirkdev · Jan 24, 2017

I have a bit of difficulty believing that over servicing is a contributor to shortened engine life as well. If proper techniques and clean tools are used there is no reason that you should be introducing dirt into an engine.

The number one reason I do 7500 km intervals on my 6.7 ford diesel is fuel dilution. You never know how much you have until its too late.. Not to mention the dealer warranty program won't be too kind to you should you have an internal failure while still on OEM warranty. After thats up to you do what you will.. I have always been a ford guy and the older ford with HEUI fuel systems destroyed oil with sheering. Most guys were doomed to fail on 6.0's if you ran past 7500km. My 2c.

LBZ · Jan 24, 2017

sirkdev said:
I have a bit of difficulty believing that over servicing is a contributor to shortened engine life as well. If proper techniques and clean tools are used there is no reason that you should be introducing dirt into an engine.

The number one reason I do 7500 km intervals on my 6.7 ford diesel is fuel dilution. You never know how much you have until its too late.. Not to mention the dealer warranty program won't be too kind to you should you have an internal failure while still on OEM warranty. After thats up to you do what you will.. I have always been a ford guy and the older ford with HEUI fuel systems destroyed oil with sheering. Most guys were doomed to fail on 6.0's if you ran past 7500km. My 2c.

I'll agree with you on a HEUI injection system or a non common rail system that fuel dilution is a real issue due to their flaws and requires more frequent changes. But so is dilution from coolant in the event of a failure in the head gasket or oil cooler. Bottom line regular sampling intervals are a better way to monitor this.

Also on a CR fuel system, especially the newer ones, fuel dilution of the oil is almost a non issue. It takes a major event to cause fuel dilution such as a cracked injector body or a hung injector. Neither of which are common unless you get a tank of poor quality fuel or run serious tuning. Either of these situations however will most likely initiate a code indicating a problem almost immediately.

DaveB · Jan 24, 2017

Update: needs cam. $6000.00 is the quote from GM. This is not a typo. Bye bye GM.

pfi572 · Jan 24, 2017

Frig ?? A completely long long block is cheaper isn't it?

DaveB · Jan 24, 2017

pfi572 said:
Frig ?? A completely long long block is cheaper isn't it?

I told him to call me back with a crate motor quote. There's no way I'll spend 6k to patch a motor with 160,000km on it.

LBZ · Jan 24, 2017

Go cram a wrecker motor in it and for sale.

pfi572 · Jan 24, 2017

DaveB said:
I told him to call me back with a crate motor quote. There's no way I'll spend 6k to patch a motor with 160,000km on it.

Yes because their crate motors are reasonably priced.
I would guess in the $3800-$4000 range.

DaveB · Jan 24, 2017

New motor installed is $10,550....motor is 6500 bucks, so 4000 in labor. Having a hard time with it. Doesn't even make sense to do a wrecker motor LBZ, although I like the idea, the $$ just doesn't work.

Crate motor has 3 year, 60,000k warranty. Might do 'er, run it for 2.99 more years and dump it....

Gotta think. This cuts into quad budget severe....

sirkdev · Jan 24, 2017

Brutal man. I take care of my stuff like I will own it forever as I am sure you do Dave. It's frustrating when it is a design failure can cost so much.

LBZ · Jan 24, 2017

What's a 2010 5.3 with 160k on it worth anyways? It may start nickle and diming you to death.

Not sure how much your into it with the dealer but myself I'd cut my losses, buy a wrecker motor for a grand or two, pay a shadetree backyard mechanic a couple g to swap it and cut my losses. Hell if I still lived in Alberta with my garage I'd do it for you for that.

Cat401 · Jan 24, 2017

What can you get for the truck as is?

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