Fuel Conditioner for Duramax, why it's not a good idea anymore...

[jpgmtech]

We have been seeing an abnormally high rate of injector failures at our shop for the summer. Some failures involve poor quality fuel, but most of the failures have been on customer rigs that are very well maintained, and these guys regularly use fuel conditioner.

Fuel conditioner has traditionally been good, especially for the older pumps. Since the Bosch CP3 and common-rail injection has come along, fuel conditioner is not necessary. Lubricity is not an issue anymore (if anyone wishes to argue that point, they forget that modern injectors are actually designed to work reliably with ultra-low sulphur fuel. If you think modern diesel fuel is 'dry', think about the thousands of Bosch injectors on the road in gasoline direct-injection engines. The gasoline direct injectors are practically the same design, just sized differently). Fuel varnish deposits can still be an issue at times but that can usually be managed if good quality, fresh fuel is used.

The engineers really hate fuel conditioner, not because the conditioner itself will hurt anything, but because of what most conditioners do with water. Very few fuel conditioners on the market have water de-emulsifiers (they force water molecules to drop out of suspension in the fuel. Last time I checked there were only two brands of fuel conditioner that have de-emulsifiers in them - Stanadyne and Racor-Parker). Most fuel conditioners have water emulsifiers (similar to methyl hydrate, and some actually do have methyl hydrate in them) that allow the water droplets to be broken down into smaller sizes and be suspended in the fuel. At this point, the water-block and separator in the fuel filter starts to be defeated, and water molecules can pass through to the pump and injectors. Fuel injectors on newer Duramax's are quite robust in general, but they have next to no tolerance for water - even small amounts introduced over a long period of time. Where does the water come from? Condensation primarily, but small amounts can be present in the fuel at the pump.

A secondary issue is Cetane boosters. Again, not a problem with stock trucks where the injection timing is set very late to manage NOx. But a tuned truck is another story. Cetane improvers accelerate the ignition process, effectively advancing the ignition timing. A truck that is tuned optimally for Type B diesel fuel will tend to knock a bit more with fuel conditioner. On the LB7 and LLY in particular, that can be hard on head gaskets. In my personal opinion it may be possible to stress crack a piston with over-advanced timing as well, usually on the LBZ and newer engines with the large wristpin bores. (many cracked pistons show melting damage from overheat, but a stress cracked piston will show no melting at all.)

And don't cheap out on fuel filters either. Cutting open several over the summer, I found that the filters with the narrow black plastic housings are only a single element design, and sure don't look like they meet the 5 micron rating based on the ashphaltine pattern. The newest GM filters have two filter elements with a third water-block element.

Hope that will save a few guys some four-figure repair bills...

 

[Ranarampage]

LMM for the win! Early model duramax has serious injector problems, some later ones had pump failure issues and have seen lots that need headgaskets. The main one we are seeing in our shop lately are chipped vehicles and turbo failures at around 200,000 km. As for fuel filters, buy gm specific ones, change it before recomended intervals, and you should be fine.

 

[jpgmtech]

LMM for the win! Early model duramax has serious injector problems, some later ones had pump failure issues and have seen lots that need headgaskets. The main one we are seeing in our shop lately are chipped vehicles and turbo failures at around 200,000 km. As for fuel filters, buy gm specific ones, change it before recomended intervals, and you should be fine.

LB7 injectors did get better, and especially when GM themselves went from a single element to a dual element fuel filter. LLY and newer injectors have been pretty bulletproof for us. LB7 and LLY head gaskets are a common issue - and the failure is usually accelerated with a power program with aggressive timing advance. I've seen lots of sandblasted compressors on turbochargers with aftermarket air filters, to the point that they won't even build stock boost levels anymore. My favourite is the LBZ. But I will take the LMM in a pinch...

 

[whitegold]

ok... I'm blond.... so are you saying we shouldn't be using conditioners??

 

[jpgmtech]

ok... I'm blond.... so are you saying we shouldn't be using conditioners??

Haha yah, that's what I am saying. But I'm basically repeating what GM engineers have been saying for years.

 

[250mark1]

Not just a duramax thing cummins/dodge also do not recommend any additives be used in the diesel trucks

 

[bigz64]

two questions

1. what about the fuel additives called injector cleaners? same thing juts named different? so just as bad?

2. the new LMLs have a very long fuel filter life monitor built in, looks like 65 000 km between fuel filters according to the computer

we have been using injector cleaners on our LBZs for a few years with no issues and we change those fuel filters out at 30 000 kms with no issues either

but now we have LMLs and dont feel like wrecking those trucks, no issues so far good trucks and motors

thanks

 

[Ol' Sarge]

I may be wrong but isn't the latest version of the DMax using the Bosch CP4 pump? That pump has caused a lot of grief in the Ford world because the components are not sufficiently hard enough to handle the dryer fuel in the US. Their fuel is only required to have a wear scar score of 520 whereas Canadian fuel is is at 460. This new pump, at least initially, was specced to require 460 wear scar fuel. So in the Ford world it was generally known that a good additive for lubricity was recommended. And I agree completely that emulsifiers are a no no in the newer modern diesels, but there are still some good choices for additives that contain demulsifiers. Here is a link to the Spicer test done a few years ago. Some good info here and some of it is still current.

 

[GYMBRAT]

Ive ALWAYS believed in this statement until a yr ago when I was swayed and then strayed from my original beliefs to NEVER use additive crap in my diesels or any vehicle for that matter! I am happy I only just started to use the additive BS cuz now I wil toss that CHIT back in the trash AGAIN lol!!!!!

GREAT post and thx a ton jpgmtech!!!!!!!!!!!!

NOW to get my LLY to STOP over heating when pulling my trailers!

 

[Lococoin]

Not just ford. GM has basically the same amount of failures of the CP4 pump as ford has had although you dont hear as much about it since they seem to be warrantying more of them, therefore less online bitching. VW/Audi have extended the warranties on some of their diesel vehicles with this pump.

I myself run the ford conditioner that isnt mandatory but is recommended.

 

[tex78]

I use sea foam in every thing. Made for out boat 2 smokes at the start. So its real good for diesels too.

Gets rid of water and not suspends it like others.

I use it as a fuel stabilizer in everything and have never had a issue since.

sent from A UNKNOWN PLACE IN TEA LAND

 

[Caper11]

I've used howes fuel conditioner for years, especially when I drove truck. The main reason I use it? the differance between winter and summer fuel. Anyone who has been froze up on the side of the road at night at 30 below knows what a crappy feeling it is. I wouldn't be blaming fuel conditioner on injector failures, I'd look into excessive idle times, quality of fuel being used etc.
Are fuel additives necessary? IMO no if there is a good supply of quality diesel fuel, but you NEVER really know what your going to get at each fillup, the tanker truck may of just dropped of a load of fuel off and stirred up the bottom, and the lubricity additives added to diesel to compensate for the ULSD now being used can be sketchy.
The old school farm conditioners such as 2 cycle oil, ATF, ect may be still being practiced in the newer engines.
Imo engineers in the warm cosy states may not exactially know what it takes to keep a diesel running in the Canadian north.

 

[jpgmtech]

two questions

1. what about the fuel additives called injector cleaners? same thing juts named different? so just as bad?

2. the new LMLs have a very long fuel filter life monitor built in, looks like 65 000 km between fuel filters according to the computer

we have been using injector cleaners on our LBZs for a few years with no issues and we change those fuel filters out at 30 000 kms with no issues either

but now we have LMLs and dont feel like wrecking those trucks, no issues so far good trucks and motors

thanks

Under certain circumstances we will use an injector cleaner in a specific procedure, usually to deal with varnish on the nozzle end of the injector. Otherwise, no need to fix what ain't broke.

As far as the fuel filter life monitor is concerned, it was based on total fuel flow, not on kilometres travelled. The newest GM fuel filters are quite an elaborate design, its possible that they can allow for a longer fuel filter life based on that.

 

[jpgmtech]

Not just ford. GM has basically the same amount of failures of the CP4 pump as ford has had although you dont hear as much about it since they seem to be warrantying more of them, therefore less online bitching. VW/Audi have extended the warranties on some of their diesel vehicles with this pump.

I myself run the ford conditioner that isnt mandatory but is recommended.

I have heard about a few CP4 failures, but we actually haven't had any failures in our neck of the woods, and we move ALOT of Duramax trucks. Between you, me, and the fencepost: there was quite a ruckus internally between GM and Bosch a few years back. Turns out both companies had to learn how to deal with North American fuel - GM had to build a better filter, and Bosch had to upgrade materials.

 

[jpgmtech]

I've used howes fuel conditioner for years, especially when I drove truck. The main reason I use it? the differance between winter and summer fuel. Anyone who has been froze up on the side of the road at night at 30 below knows what a crappy feeling it is. I wouldn't be blaming fuel conditioner on injector failures, I'd look into excessive idle times, quality of fuel being used etc.
Are fuel additives necessary? IMO no if there is a good supply of quality diesel fuel, but you NEVER really know what your going to get at each fillup, the tanker truck may of just dropped of a load of fuel off and stirred up the bottom, and the lubricity additives added to diesel to compensate for the ULSD now being used can be sketchy.
The old school farm conditioners such as 2 cycle oil, ATF, ect may be still being practiced in the newer engines.
Imo engineers in the warm cosy states may not exactially know what it takes to keep a diesel running in the Canadian north.

Well, the fuel conditioner by itself is not the typical cause of injector failure - but what that fuel conditioner does with water in the fuel can contribute to a failure. And actually Howies is exceptionally good at picking water up instead of allowing it to separate out of the fuel. Ask me how I know...

 

[pfi572]

What about this additive .
www.stanadyne.com/
GM dealer told me to use this if using any.

 

[Caper11]

Well, the fuel conditioner by itself is not the typical cause of injector failure - but what that fuel conditioner does with water in the fuel can contribute to a failure. And actually Howies is exceptionally good at picking water up instead of allowing it to separate out of the fuel. Ask me how I know...

So if I'm understanding correctly, that you do agree that in a perfect world fuel additives are not needed, but since diesel has some degree of water content in it, a fuel conditioner like howes that demulsifys water instead of emulsify it, is alot better means of dealing with the water in the fuel.



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[Caper11]

What about this additive .
www.stanadyne.com/
GM dealer told me to use this if using any.

That is also a good product, it's made by a fuel injection manuf.


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[LBZ]

LB7 injectors did get better, and especially when GM themselves went from a single element to a dual element fuel filter. LLY and newer injectors have been pretty bulletproof for us. LB7 and LLY head gaskets are a common issue - and the failure is usually accelerated with a power program with aggressive timing advance. I've seen lots of sandblasted compressors on turbochargers with aftermarket air filters, to the point that they won't even build stock boost levels anymore. My favourite is the LBZ. But I will take the LMM in a pinch...

I agree. Some of the cheapass aftermarket filters are junk. I ran an S&B and K&N and found them to be of higher quality than AFE, or even Banks. And FWIW, there is really no advantage to just running a CAI on LB7 or LLY engines without also upgrading the mouthpiece of the intake to one from an LBZ which is much larger and flows better. The stock box and a K&N is fine so long as you use proper and regular cleaning procedures.

Also, as someone who has had a hand in building Dmax's with parts good for up to 1500hp, I feel I have to toss in my 2 cents here on the Cetane Boost and Fuel Additive discussion.

I would not run conditioner all the time, but about every 6-10 tanks or so depending on the time of year and where you get your fuel, and only those that actually remove the water from the fuel, not just encapsulate it-use ones like Seafoam or the two Jpgmtech mentioned in his first post. More importantly, DO NOT cheap out on filters. On a Dmax, I'd cough up the bucks and use the GM 2 micron filters that were introduced in the later model engines, and change it every second or third service depending on fuel quality or buy an adapter that company's like Underground Diesel Performance sell to switch to a CAT 2 micron filter. Common rail engines are very sensitive to contaminants. This was part of the issue with the early LB7 as they started out with only a 5 micron filter. A water separator system like the ones included with Air Dog and FASS lift pump systems are also a very good addition to helping keep the fuel clean and water free.

Now Cetane boosters. They don't technically advance timing, but rather they raise the flash point of the fuel which causes the fuel to ignite faster and slightly sooner. The injection timing of the engine stays the same as per it's programming. This does help in reducing cold start smoke, fuel knock, and other cold starting issues. But adding too much Cetane boost can also have negative effects in hot or up to temp engines. The fuel ignites too quickly which creates a change in the peak pressure band of the compression stroke and can result in a loss of power-this is the fuel knock you may hear which isn't necessarily doing damage, but doesn't make it run as nice. Older noisy diesels and mechanical injected engines were noisy due to the single injection sequence. As a result, running boosters has a bit more of an effect as to how the newer CR engine runs and sounds-but as for affecting it enough to cause damage, I doubt it. Newer CR diesel's are much quieter due to several injection sequences used to smooth out the ignition of the fuel, and also control emissions with the addition of up to 3 post injection sequences. Ideally 3-4 numbers is as high as you want to raise the Cetane value above the the recommended value of the engine manufacturer. Anymore than that, your wasting your money as does using more than the recommended quantity. Also I would only use Cetane boost regularly in the 6 liter Ford diesel (prone to egr issues) or in area's where you have only arctic diesel, no winter. This aids in raising the exhaust temps to reduce carbon and soot build-up that fouls EGR valves and EGR sensor's in the Ford 6.0 and some other engines while they are only running Arctic fuel. Also due to the easier igniting fuel, it runs a little smoother, and starts a little easier when cold. Other than that if your running ULSD regular or winter fuel, there is no need for Cetane boosters really so save your money.

I highly disagree with boosters being the cause of headgasket failures. In my experience, I have run and tuned engines running SEVERAL degrees advanced timing with larger fuel pulsewidths with no issues. There is a point of too much, but a good tuner and most canned tuners and ones like Edge, Banks, know what these limits are and what PW to run and the tow tunes and mileage tunes will usually stay within this safe range. Too much cetane booster will not advance the speed of ignition enough to take it out of this safe range. I don't care what anyone says. It's the higher hp and race tunes that will exceed these limits of a stock engine and cause higher cylinder compression which can result in cylinder head warpage or stretched headbolts causing gasket failures, and in extreme cases crack pistons, burn holes in pistons when injectors get hung, or bend rods. I also did run water/methanol injection which also raises the cylinder pressures. I never had an issue as I adjusting timing in my tuning to compensate for this keeping cp and timing in a safe range.

Now as for cracking pistons, I also don't believe timing alone will cause this. A higher pw of fuel is required to increase the cylinder pressure, not just injecting it in too soon. Although this was a problem with some of the LBZ and LMM engines, most have been due to poor quality control when GM first outsourced the piston's to China. The other models rarely had this issue at stock power levels and in the event it was too high, LB7 and LLY engines usually bent rods before cracking pistons. Obviously, these higher PW and timing also increase the heat in some cases to the point where they can melt aluminum which is where the pistons and in some cases EGR coolers say buh bye!!

Too sum it up, I wouldn't worry about using conditioners all the time, but once in awhile using a good quality conditioner can't hurt to remove water.
Cetane booster's IMO are not necessary except in the 6.0 Ford which had issues from day one with ULSD.
IMO Cetane boost alone won't cause a cracked piston, or a bent rod, or a bad headgasket. Other factors have to be in play to make this happen.
Use good filters, change them regularily.

Also, change your coolant and clean the cooling system regularily-including cleaning the fins on the rad and cooler stack in front of it. This will help issues with cooling which can result in headgasket failures-especially in the LLY!! I'd go with every 3 years as a baseline.

 

[jpgmtech]

@LBZ, I may not have been clear enough in my original post - I agree with everything you have stated. Regarding Cetane boosters, I was in fact thinking of the effects on tuned trucks both with head gaskets and cracked pistons - especially the trucks that run big pulsewidth and timing changes (and there are quite a number of them out there that many guys have no problem hooking 15,000+ lbs to and yanking it all over the mountains)

Typically with the LLY, head gasket failures will happen sometime during the course of the engine's life even if left completely stock. On average though, tuned trucks will split the combustion seal ring at lower mileages than stock ones, in my experience. And it's not necessarily that the tuner was running crazy pulsewidth or advance, its just that the combustion pressure spike of a tuned truck vs. a stock truck does increase regardless, increasing the stress on what I consider a poorly designed gasket. The newer gaskets are rarely if ever a problem - only failing if there is a crazy overheat or some other external issue.

When I finally arrived at a good tune for my LLY, I was using a chamber pressure transducer and logging software to set the timing numbers. That was highly educational! The initial pressure spike from the main injection light-off can grow exponentially with timing advance, even without the extra fuel (and just as a footnote, there is quite a bit of room for more timing advance than stock with the Duramax as it is tuned to minimize NOx production). That spike can act like a hammer. Even if you do not change the 'mass' of the hammer (the overall energy of the fuel charge) you can increase the 'velocity' of the hammer by over-advancing the timing (a little over-simplified but I'm pretty sure you already grasp the idea). It's easy to go from 1800-2200 psi to 3000+psi on that initial pressure spike, especially if the intake air charge is quite hot coming off the intercooler. Of course, you can usually hear the knock when the pressures spike that high on the initial light-off. A large pressure spike can also set up shock-waves in the piston itself. Cracking can occur when a particular resonance is achieved, not just a specific pressure. And yes, heat does factor in most cases of cracked pistons that I deal with - especially if the oil temps get a bit high and the piston oil cooling system can't remove the heat buildup.

Oh and the LBZ turbo mouthpiece, I did write a magazine article on that a while back. That's definitely a need to replace part on the LLY's!

Anyway, I digress a little but cool stuff, and nice to find someone else speaking the same language. Far too many so-called 'diesel techs' out there that haven't taken the time to really learn what they are doing...