Oil analysis with injector knock

[Shifterpilot69]

I have 30,000 miles on my 2004 DWR 4x4, and It's had the injector knock since about 4000 miles. 2 of the injectors have been replaced, and another is on back order. The dealer will order more than 1 injector at a time. I travel alot with the truck, and can not sit around waiting for injectors so I just drive it until I get a chance to get into the dealer to get it replaced. I was told by the service writer and the "Head Cummins Guy" ( yea right!) that there is no problem driving with the bad injector. The fuel mileage is less since the Knock than it was the first few thousand miles, so I guess that is a problem.



Now to the point of this posting:



I get my oil analyzed at every oil change since new ( I know, a little compulsive). Well here is what I have found.



Since the first analysis, my Aluminum and Potassium seem to be very high. On

my 1996 Cummins, the analysis was way under the universal averages from my first analysis until the last at 235,000 miles with 7,500 to 10,000 miles between changes. This 2004 unit seems very high as listed below.



-------- Universal---------5246 miles--------12976 miles-------19492 Miles

-------- Averages--------Change & ---------Change & ---------Change &

---------------------------Analysis------------Analysis------------Analysis

Aluminum----4--------------7------------------11----------------16

Potassium----1-------------29-----------------67----------------64



All numbers are in Parts per million.



The analysis comments suggest a coolant leak in the upper end which is affecting wear on the pistons.



What I am worried about is internal damage that will not be appearent until after the warranty. The dealer told me that they can not do any checking unless something breaks.



Do these numbers show any concern?

What should I do?

Could the injector knock have any affect that could cause this?



Thanks in advance.

 

[DLeno]

I can't answer the question correlating injector knock with a coolant leak. Doesn't sound related but I'm not an expert.



But in any case, keep the analysis going, so that you can show this trend even if they that ignore it. Is your 04 a 305 or a 600?.

 

[Shifterpilot69]

Its the 555 2004. 0

 

[amsoilman]

Do these numbers show any concern?[QOUTE



Potassium is generaly used as a Detergent in engine oil.



Wayne

amsoilman

 

[DLeno]

Its the increasing trend of aluminum content in the oil that bothers me. From a statistics perspective, three points trending upward is not a total slam dunk, but it does mean there is low probability that these points could have happened this way randomly. So your next change is very important -- to see if this trend continues.



I'm not an engine forensics expert by any means; just interested. where would this aluminum come from? something tells me that, since chrome and iron are not trending upward, that nothing in the block (save perhaps pistons) or head is wearing, the rings are not wearing, nor are the valves or cam, crank. What about bearings -- they have aluminum I think...



In order for the aluminum content to be explained by piston wear, you'd have to have some scuffing, ring groove wear, etc. perhaps there is an aluminum thrust bearing somewhere. I suppose its possible for an out-of-tolerance condition to cause piston wear.



I don't understand why a piston would wear as a result of a coolant leak undetected by other elements in the oil. I mean, if there is a coolant leak sufficient to cause accelerated piston wear, wouldn't you see other ugly things (like Sodium from the coolant?)

 

[Vaughn MacKenzie]

I've done lots of oil analysis and even running 20,000 miles on a change my Al never ran that high (10 was the worst).



Questions: What is your Iron count, fuel dilution and soot dilution? What about Silicon?



Vaughn

 

[nickleinonen]

what's the lube oil cooler made out of internally? if it is aluminum, is it leaching into the oil from there?

 

[Shifterpilot69]

Thanks for the replys so far.



Here is some more info on the analysis.



I could not find a soot reading, but I will include the whole report.



Viscosity------should be 68-78 my reading 72. 5

Flashpoint-----should be >405 my reading 435

Fuel % --------should be <2. 0 my reading 0. 5

Antifreeze-----should be 0. 0 my reading ? I guess they are assuming that the potassium "could be" from the antifreeze.

Water---------Should be <0. 1 my reading 0. 0

Insolubles-----Should be <1. 0 my reading 0. 2



I know the first change or 2 would be out of spec due to factory leftover, assembly lubricants, and breakin. This, however, seems excessive.



-----------------------Factory Oil---------- Rotella------------Mopar Oil

-------- Universal---------5246 miles--------12976 miles-------19492 Miles

-------- Averages--------Change & ---------Change & ---------Change &

---------------------------Analysis------------Analysis------------Analysis

Aluminum----4--------------7------------------11----------------16

Potassium----1-------------29-----------------67----------------64

Chromium----2--------------1-------------------1------------------1

Iron---------24-------------32-----------------30------------------24

Copper------4--------------16-----------------6-------------------3

Lead--------3--------------3------------------0-------------------2

Tin---------1--------------0-----------------1---------------------2

Molybdenum-12------------85-----------------11-------------------2

Nickle--------0-------------0-------------------0-------------------0

Manganese---1--------------4------------------0--------------------1

Silver--------0--------------1------------------0--------------------1

Titanium------0--------------0-----------------0---------------------0

Boron--------117------------105---------------16--------------------1

Silicon-------8----------------31----------------17------------------6

Sodium------5----------------15-----------------5-------------------2

Calcium------2677------------4152------------4101-----------------2343

Magnesium---337--------------8----------------7-------------------222

Phosphorus--1067------------1091-------------918----------------1007

Zinc---------1238------------1270-------------1105---------------1195

Barium-------1-----------------7-----------------1-----------------0

 

[amsoilman]

Thanks for the replys so far.



Here is some more info on the analysis.



I could not find a soot reading, but I will include the whole report.



Viscosity------should be 68-78 my reading 72. 5

Flashpoint-----should be >405 my reading 435

Fuel % --------should be <2. 0 my reading 0. 5

Antifreeze-----should be 0. 0 my reading ? I guess they are assuming that the potassium "could be" from the antifreeze.

Water---------Should be <0. 1 my reading 0. 0

Insolubles-----Should be <1. 0 my reading 0. 2



I know the first change or 2 would be out of spec due to factory leftover, assembly lubricants, and breakin. This, however, seems excessive.



-----------------------Factory Oil---------- Rotella------------Mopar Oil

-------- Universal---------5246 miles--------12976 miles-------19492 Miles

-------- Averages--------Change & ---------Change & ---------Change &

---------------------------Analysis------------Analysis------------Analysis

Aluminum----4--------------7------------------11----------------16

Potassium----1-------------29-----------------67----------------64

Chromium----2--------------1-------------------1------------------1

Iron---------24-------------32-----------------30------------------24

Copper------4--------------16-----------------6-------------------3

Lead--------3--------------3------------------0-------------------2

Tin---------1--------------0-----------------1---------------------2

Molybdenum-12------------85-----------------11-------------------2

Nickle--------0-------------0-------------------0-------------------0

Manganese---1--------------4------------------0--------------------1

Silver--------0--------------1------------------0--------------------1

Titanium------0--------------0-----------------0---------------------0

Boron--------117------------105---------------16--------------------1

Silicon-------8----------------31----------------17------------------6

Sodium------5----------------15-----------------5-------------------2

Calcium------2677------------4152------------4101-----------------2343

Magnesium---337--------------8----------------7-------------------222

Phosphorus--1067------------1091-------------918----------------1007

Zinc---------1238------------1270-------------1105---------------1195

Barium-------1-----------------7-----------------1-----------------0

Everything here looks fairly good, with the exception of the Alluminum. I really have a hard time thinking the Alluminum is coming from the pistons, as they would normally not be scuffing on the cylinders walls. If in fact they are scuffing, then there is a problem, and you should see some wear in the rings, which the lead, tin, copper and chrome numbers would be much higher than yours is testing. The Iron at 24 last analysis, is not out of tolerance for only having 6500 miles on oil. Potassium @ 64 could be coming from the antifreeze. Potassium is even found in fuel. Since the sodium is not high, I have a hard time thinking the coolant leak as well. Calcium, Magnesium, Phosphorus, Zinc, Boron, Molybdenum and Barium are all oil additives, but can not comment as to what is in the oil or the amounts in the oil you are using.



Aluminum, Chromium, Iron, Copper, Lead and Tin are the "wear" metals found in the engine. There is no Nickel, Silver or Titanium in the Cummins engine that I am aware of.



If I were you, I would contact the lab that did the analysis, and start aasking questions about the report.



Wayne

amsoilman

 

[DLeno]

Another thing that occurs to me is that you've changed oil brands on every change. So thats a variable to consider, particularly on the additive package elements (Boron, Magnesium, Calcium, Barium, Phosphorous, and Zinc). consider changing oil next time with Mopar oil just to keep that variable anchored.



but Aluminum is considered a wear metal, from some quick reading, and can come from the turbocharger, some thrust bearings in the cam perhaps, and of course piston wear. I don't know how much of that applies to the CTD. piston wear could come from scuffing, ring grove wear, or even a burned piston.



I'd say you need to answer the question of antifreeze. If the potassium is from anti-freeze, I would think the test would also detect glycol and/or water.



this is pretty interesting stuff. please post your results of the next test. you might consider changing it early (say, 5,000 miles) making sure to adjust the data accordingly -- to stay DEAD EVEN (consistent) with the current rate of aluminum wear, a change at 5,000 miles should give you a 23% reduction in aluminum levels from the current level (because 5,000 miles is a 23% reduction from 6,516 miles). In other words, if you change oil at 5,000 miles, anything over 12 PPM aluminum is more aluminum wear than your last change where you measured 16 ppm.

 

[Shifterpilot69]

Wayne

Thanks for the info on where the elements would come from.



Dleno



A burned piston is what I am worried about since I have been plagued with the (injector knock) since about 4000 miles. Dodge cannot seem to fix it. They have replaced 3 injectors already, and I went in yesterday for them to change another one, but they told me I need to leave it for the day to do some other tests. I did not have the time to leave it this time.



I did change oil at the first change to Rotella. After the first analysis, and after the smell, I changed it back to Mopar. The dealer told me the smell was from the Rotella (even though I had a 1996 Cummins that did not smell with a total of 250,000 miles). I was trying to get the dealer to fix the smell problem but they would not even look at it until I put Mopar back in. They also told me that any wear in the engine would not be addressed if I was not using Mopar. I know that was B. S. but I wanted to take out as much of the argument as I could. The last oil change was at 25,000 Miles for a 6500 mile interval. I again used Mopar and it was done about a month ago, but I forgot to send it out until today. I will post the findings in a few days when I get them back.



Thanks again for the responses

 

[DLeno]

good deal. that analysis will be very interesting. I'm not enough of a combustion expert to say if injector knock can burn a piston. about the only thing you can do is keep the history showing aluminum wear, and let your service manager know via letter (cc the dealership GM) so that you have record that they know.



Talk you your lab about this, but it seems to me that of the major sources of aluminum, you can rule out a coolant leak unless you have other evidence such as glycol, water, or sodium as well.