Fuel Injector - Again

[Ken Sair]

Well, Ann and I are spending the night at Peterson CAT in Santa Rosa, Ca awaiting our new fuel injector tomorrow morning (so we are told). We have one replaced before in November 2008.

I have been following CAT's maintenance recommendations religiuosly, but have recently been advised to change. The first one was by the CAT dealer in El Paso, TX, who said I should be changing my oil/filters at 14,000 miles.  CAT recommends 20,000 miles or yearly. I have an intermittent cylinder dropout for the last year, and finally now have a fault code. We have confirmed cylinder number 5 is dead.

Anyway, the shop foremean here, recommended I change the oil/filters at 10,000 miles. He said it had to do with the severe high pressure the oil gets pumped through the HEUI pump (3,000 psi).  Specifically he mentioned the C7 and C9 engines. He said they were more prone to fuel injector failure than the larger CAT engines.  He specifically mentioned soot in the oil. Anyway, thats what I have been told. I do know.  I lost both injectors with about 12,000 miles on the oil.  He also recommended that I change the fuel filters more regularly (5-6,000 miles).  Says it very inexpensive insurance.  Fuel Injectors run about $700 with labor.

Any thoughts out there?

Ken Sair 2007 Contessa (C9)

[Gerald Farris]

Ken,
I have seen a lot of management personnel (shop foreman-service manager) in dealerships (car, truck,and equipment) who knew less about the technical reasons for a failure than you do. Their job is managing personnel and selling service work, and sometimes it makes no difference if you need it or not. They are not all that way (I was a manager for ten years) but a large number are. I personally think that changing the fuel filter every 5000 miles is a waste of time and money.

I would call Caterpillar and talk to an engineer about the recommendations that you were given. You may have to be a little persistent to get to an engineer, but the first person that answers the phone probably knows little more than reading the answers from a computer screen as he types in your question.

My thoughts are that since Cat is paying for the warranty repairs on your engine for five years, if the more frequent oil and filter changes were necessary they would state it in their operating maintenance schedule. Cat has performed a lot of test and spent a lot of money under controlled conditions to come up with the maintenance schedule for your engine. I think that Cat knows more about it's needs than your shop foreman.

Gerald  

[Edward Buker]

Ken,

As far as oil changes go I was recommended by a very reputable Cat lead service individual in the Denver area to use 12k miles as a change interval vs the 15K miles in the manual for a C12. It would seem as a minimum that they could pull a sample and have it analyzed at 10K miles to aid in the decision with some data. The analysis is quite inexpensive. Compared to parts oil is cheap....

Regarding filters, Cat has created High Efficiency type filters for both oil and fuel that may not be the numbers recommended in your manual. They are significantly better and should be used. They say high efficiency on the outside. You can check if you are using those now and if not consider having them changed. The raw diesel fuel that we have today is probably cleaner and better refined and filtered than ever before. Unless you get an abnormal event like a contaminated tank of fuel then the filters should last the recommended service life.

There are two issues with changing fuel filters early. First you have added risk of introducing contaminants into the system whenever you break into the system to do the filter change. Second and more important, the way filters work is that the filter media begins to accumulate contaminants on the surface with time. These filters are 98% efficient at removing 2 micron particles from the start. With time as the surface pores accumulate various size contaminates they actually improve their filtration efficiency until the point where a pressure drop across the filter begins to reduce flow. The best systems used in industry measure that drop and change filters with the pressure drop data as needed.

If you had a pressure drop issue you would see that as reduced power, lower turbo boost pressure, and the like. I'm not recommending that you go beyond the normal service interval but the idea that changing them often "as cheap insurance" is not well founded with any science in my opinion.

Later Ed

[Richard And Babs Ames]

We have suffered two injector failures in 10 years and 110,000 miles on our 3126 engine. Both were electrical so not related to lubrication (correct me if wrong Gerald). We follow the published guidelines in our CAT engine manual and feel in the lighter duty Motorhome usage of the engines is still fairly conservative.

[Ken Sair]

Thanks all. I couldnt agree more. Maybe I'm more just a victim of circumstances and timing. My thought are also that CAT spends a lot of money on research that is based on millions of miles.

We discovered another problem here also. I had trouble getting engine access because one of the latches for engine access was stripped. I got it fixed, but was irritated at Wagoner CAT in El Paso TX.  They did a lash valve adjustment in
April. Well, as the tech here was finishing up, he found two of the bolts on the valve cover were also stripped and then they (Wagoner CAT) tried to use a strip of silicone to control a small oil leak. Man am I angry. Its all covered under warranty but Wagoner CAT in El Paso TX really screwed up. Then half-assed the repair instead of admitting their mistake and fixing it.

Thats Wagoner Equipment in El Paso TX, out near the military base. Avoid them if you can, I sure will.

ps to Gerald. Its very difficult to find someone who knows less than I do about engines.

[Richard And Babs Ames]

Ken post your service  experience at http://www.rvservicereviews.com/ and check it before getting service at an unknown location. The more reviews the better the data base is.