I found this a while ago while web surfing and sent it to Cummins. I told them that I was going to start using a 15# radiator
cap to hopefully inhibit liner pitting, and asked them what they thought about it.
I never got a reply.
Cavitation Erosion Of Cylinder Liners And How To Eliminate It. - Free Online... (http://www.thefreelibrary.com/Cavitation+Erosion+Of+Cylinder+Liners+And+How+To+Eliminate+It.-a054344138)
Interesting read.... but how many of us will run our engines enough to ever have to worry about this? It never even entered my mind as something to worry about on an occasionally used rv.
Most cummins have mid bore support in their liners to lessen the damage. It's thicker
How long does it take for liner pitting to occur to the point that re-sleeving is required?
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How long does it take for liner pitting to occur to the point that re-sleeving is required?
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All depends what coolant you use and how you keep up with it.
If you don't keep up with it, how long?
That is an unknown, it depends on how the PO took care of the engine.
One of the reasons that I test the coolant if "regular low silicate for diesel with added SCA" coolant. Be aware that coolant test strips have a limited shelf life. Do NOT use if expired.
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=22873
Practical question. Please find me an example of a persons engine that failed due to liner pitting. Even a "friend of a friend of a RV park neigbor's uncle's brother's sister-in law" story would be fine. I only ask because I've never yet heard of a single engine failing due to liner pitting/cavitation. And this includes boats.
I have seen it in Cat and Cummins engines in heavy equipment. loaders scrapers and trucks. It does not destroy the engine it puts water in the oil. If you have a leaky liner you can drain the water off in the morning as it goes to the bottom of the pan during the night. I was an operating engineer heavy equipment repairman until I retired from the union. I could drain the water for months until the equipment could be shut down for repair. There was a chemical years ago that I don't know still exists called Stay=Clean that some how stopped the problem. The main difference was only water was used as coolant in the equipment.
Up until a couple of years ago, the Cummins tech who did the Cummins Maintenance Seminars at the big FMCA Conventions brought in a failed cylinder liner-- the owner of the low mileage engine replaced the coolant with "regular" Prestone. He certainly made his point, but suspect it over-scared too many. The new guy who does it no longer brings it to "show and tell".
There IS a reason that all HD diesel engine manufacturers call for the same coolant specs for their linered engines. Not sure why anyone would not follow their advice on proper coolants (there are many), proper testing and proper change interval.
I think it's because there is a natural tendency among people who have always done for themselves to regard expert advice with great skepticism.
I have seen industrial engine liners with pinhole leaks after years of use.Most of the time it was wrong coolant or no coolant at
all ,just water.
That's because the "expert" advise is very suspect in many cases. Our Detroit also has wet liners. I went down to the Sacramento Detroit Diesel service center and asked the shop foreman what coolant they use. He said, "we use anything that is green", not a confidence building reply.
So, yes, its a natural tendency! A lot of shops are "expert" in liberating your wallet with parts "discounts" offset by tripling or more the hours they charge you for a two hour job.
Pierce
When in doubt about expert advice, why not listen to the maker of your engine as written in your owners manual?
Suspect the engineers at Cummins, Cat, DD, etc know more about coolant chemistry than "Bubba".
Proper coolant and maintenance seem like a better alternative to those big (Rebuild for $12,000.00) posters hanging on the wall at Cummins.
We all choose our trusted sources. The one you cite would not inspire my confidence. My dad was an ace mechanic who ran a gas station for years. He didn't trust the work done by the people he hired. But he had to hire people in order to run the business because he never found a way to do it all himself.
I have seen more than a few in diesel trucks have to be rebuilt because of liner pitting... Easy enough to check and keep nitrates in check so then no problem.
The problem is that there are TWO completely different types of coolant approved by all the diesel manufacturers and the two do not "play well together".
Best advice: KNOW which you have. Keep a spare gallon of of that coolant concentrate in the coach to eliminate the chance of adding the wrong kind.
If "low silicate for diesel coolant with added SCA", test the coolant every 6 months and maintain SCA concentration. SCA can be added either by changing the coolant filter with one containing the correct quantity of SCA (expressed in "units") or as a liquid. Change per recommendation by the coolant manufacturer for that coolant OR if pH drops (becomes acidic).
If one of the new generation OAT-based coolants, basically put it in and forget it unless you drive over 300,000 miles during that period. IMPORTANT-- DO NOT LET BUBBA PUT ON A NEW COOLANT FILTER WITH SCA IN IT. YOU ONLY USE FILTER "BLANKS" WHICH GIVE THE FILTRATION, BUT NO ADDED CHEMICALS THAT WOULD CONTAMINATE THE COOLANT. I have inspected quite a lot of coaches where SCA-containing filters were used on systems with OAT-based coolants, contaminating them.
IMO as an owner, it is YOUR responsibility to know what you have and its proper "care and feeding"-- whether you do all your own work or hire all of it out makes no difference.
Very good advice from Brett here, don't count on any of the repair shops, even Cummins, to identify coolant type and add proper coolant. Most mechanics think you can I.D. coolant by color, not so, there is no industry wide color standard. Recently went thru this and after three coolant change$ now have the right stuff. I think.