What does Your DPF Look Like? ...

[Rawze]

Sharing what I have seen ...


Lets face it,.. Every truck after 2006 has a DPF (Diesel Particulate filter) and DOC(Diesel Oxidation Catalyst), and when you are getting "DPF Clogged, or "DOC Clogged" lights in the dash, you definitely need to find out if your problem is real, or if it is a ghost because of bad sensors.

I FIRST recommend to EVERYONE that has one of these newer truck to do an EGR tune-up. Here is more on that ..

Fixing your EGR/DPF Problems

I am not going to cover that a second time,.. This article is more about when you have to remove your DPF for cleaning.

FIRST Of ALL!!! -- DON'T FORGET ABOUT THE DOC Filter. It is part of your DPF system, and is actually the very first thing that all the soot from your engine goes through.

- Your DOC (Diesel Oxidation Catalyst) is the diesel truck equivalent of a catalytic converter for a car. It has precious metals in it like platinum to perform its conversion of making less harmful gases out of the more harmful ones coming out of your engine. They have slightly bigger holes in them, so soot does not normally build up on the face of them so much (theoretically),.. but the reality is that they do clog, and they DO go bad. Here are some of the reasons...

-- They clog up if you have ANY kind of coolant, fuel, or oil leak that gets into the exhaust. This could be from a bad head gasket, worn or carbon packed piston rings, dropped liner, bad EGR cooler, leaky turbocharger, and don't forget about the possibility of a leaky Doser injector too. Leaky EGR coolers and leaky doser injectors (leaking fuel and/or coolant) are the most common causes.

Also,... ANY of those liquids will wash out those precious metals fairly easily, so a couple gallons of coolant loss from a bad EGR cooler over a 6-month period, or a gallon of oil every couple thousand miles, and the DOC will get washed out making it difficult for your truck to do a regen cycle. It will also destroy and/or clog up a DPF can as well.

IF your truck has a lot of miles on it, it seems that at around the 400 - 600k mileage range, the DOC starts to get weak, even if there is nothing else wrong with the engine. This is likely due to condensation the engine gives off every time it warms on on a cold day. I would think that trucks that are in northern climates, etc. would have shorter lifespans on these components, but that is just some speculation.

In helping others,.. I have found that when you remove them,.. you can learn a whole lot about what caused one to clog up by looking at it, and the DPF's face closely.

Here are some pictures I have taken of different people's DPF cans over the last couple years ...


The small "beads" of soot build up are the tel-tale sign of a liquid, contributing to the death of a DOC or DPF can. This one has a problem with oil intrusion from worn out piston rings. Hard to see the beads in the photo, but they are there. They are usually dry, so rubbing them with a finger simply turns them to powder again, or sometimes there is slight oil residue in them too if it is bad enough.




The buildup on this one is more "clumpy", as well as beaded, and has a white under-layer when you scratch at it. This is a coolant problem for sure...



The can in the picture above, the guy drove with it like that for a month or so,.. and it killed all 6 of his injectors, made his engine run/idle rough, and eventually overheated his turbocharger. He just kept ignoring that "check engine" light, thinking everything was going to be ok. -- It ended up costing him a LOT of extra money in the end.


Well,... this next one --- Should be self explanatory. It MELTED!

it was because the doser injector was leaking fuel badly all the time. The poor guy who owned this truck was getting 4 mpg at 55 mph no matter what he did. He had taken his truck to 3 different OEM shops with no positive results either. They said everything was fine because it would still pass a regen cycle, so they never bothered to take anything apart or check his doser injector. They claimed he simply had bad fuel.



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I thought I would share these photos that I had on my phone for others to speculate on just in case they end up having to pull a DPF and DOC can off to have them cleaned. I always encourage others to post pictures of their "cans" when they pull them off, so that others can see them, and make helpful comments towards what might have caused the problems.

Last I checked, it does not cost too much to have them baked and cleaned at a local stealership (few hunderd bucks usually), so price it around if you have to have this done.


DO NOT USE A LIQUID TO CLEAN ONE!!!!!


Never use a liquid on one... There are guys on the Internet and after-market places who use liquids who claim they do this, but it is a BAD IDEA PERIOD! -- I HAVE SEEN LOTS AND LOTS of people try this with everything from alcohol to brake cleaner, to distilled water to bleach, to soap, etc... IT MESSES THEM UP and weakens them and it becomes more and more difficult for your truck to regen and keep itself clean after.

As well, some of the newer trucks require a "Maintenence Reset" and a "DPF Replacement" procedure to be performed via cummins Insite if you have one baked ans cleaned. This is because there is a counter that assumes the amount of soot levels in the DPF can, even if you have a new can under there. You must reset this counter if you have one cleaned.




If you get one cleaned,.. look at it VERY closely for any kind of "step" in the ceramic element and feel across the top of it with our fingers. if there is,.. the can is no good, and the element is cracked. -- what will happen if you re-install it, is that it will shift internally, and block your exhaust up.

A blocked exahust from failing DPF cans can and WILL lead to excess heat buildup in the turbo, manifold, and engine, and can shorten the life greatly of your turbo, injectors, etc, and can even kill/crack a piston. -- Driving around with check engine lights and DPF alarms is nothing to play with.