Cavitation Symptoms

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Steve CDN

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We hear about preventing engine cavitation in the cooling system of Cummins and other wet sleeve engines, but what are the signs of cavitation...how does one know there is a problem?
 

BernieD

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Steve said:
We hear about preventing engine cavitation in the cooling system of Cummins and other wet sleeve engines, but what are the signs of cavitation...how does one know there is a problem?

Steve

I can't tell you what the signs are or how to recognize a problem due to cavitation, but it is so simple to avoid there shouldn't be any reason to be concerned if you follow the proper procedure. Whenever you have your coach serviced, take a reading of the anticavitation chemical in the cooling system (CRS is blocking the 3 letters from my memory right now). If you use the proper diesel engine anti-freeze, it usually is precharged with the chemical and the water filter/separator usually has the chemical as well which is added over a period of time.
 

Tom

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Bernie, I think you're looking for "DCA". For anyone interested, we have an article in our library on correct antifreeze DCA maintenance. Click on the Library button above, select Maintenance items and click on Cummins Antifreeze Maintenance.
 

Steve CDN

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Bernie,

My experience with most service technicians I have encountered is few have a clear understanding of the correct procedure to test DCA.  I have been testing my own since acquiring the coach, and change the anti freeze using OEM Cummins Compleat low silicate antifreeze precharged with DCA.

I have seen demonstration samples of the effects of cavitation on display, but do not know how to recognize the symptoms of the problem when it occurs.

Many motorhome owners have not tested their cooing systems because dealers frequently don't bother explaining the procedure and since most service techs don't know how to do it correctly, I suspect there are many coaches displaying the effects of cavitation.

I'd like to know how to recognize the effects of cavitation for that reason.
 

Ron from Big D

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Steve:

      I don't think there is any real symptoms except excessive pinging or pre-ignition.  And of course, all diesels rely on compression ignition, so it's difficult to know the difference.  You will sure know when it has occurred because you will have coolant in your oil.  At that point, you have an engine re-build facing you.

 

BernieD

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Steve said:
My experience with most service technicians I have encountered is few have a clear understanding of the correct procedure to test DCA.  I have been testing my own since acquiring the coach, and change the anti freeze using OEM Cummins Compleat low silicate antifreeze precharged with DCA.

If the service technician is unable to test for DCA, I would not consider trusting my coach to that technician. It is too simple a technique for them to not know how to test for DCA..

Many motorhome owners have not tested their cooing systems because dealers frequently don't bother explaining the procedure and since most service techs don't know how to do it correctly, I suspect there are many coaches displaying the effects of cavitation.

I would tend to doubt that "there are many coaches displaying the effects of cavitation." I have never specifically added DCA to either of our coaches over the last 7 years, tho I carry a bottle of it. Between the DCA in the anti-freeze and the amount added from the filter, my DCA level has always been in the appropriate range. Every service facility that I have used had technicians who properly tested for DCA and installed the appropriate filter for the necessary amount of DCA. The standard filter comes with 4 units of DCA IIRC.

 

Ron from Big D

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Bernie:

    You are lucky to have a newer coach and engine, but older rigs were not equipped with filters that took care of their needs.  There are a lot of older rigs with new engines at less than 100,000 miles that are victims of cavitation.

 

BernieD

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Ron from Big D said:
Bernie:

    You are lucky to have a newer coach and engine, but older rigs were not equipped with filters that took care of their needs.  There are a lot of older rigs with new engines at less than 100,000 miles that are victims of cavitation.

Ron

I concede the point  However, outside of replacing the cylinder liners, I know of no repair for cavitation, so knowing that you have it doesn't help much. Prevention is the best cure.
 

Ron from Big D

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BernieD said:
Ron

I concede the point? However, outside of replacing the cylinder liners, I know of no repair for cavitation, so knowing that you have it doesn't help much. Prevention is the best cure.

Without a doubt!

 
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FleetGuard (the maker of DCA4, a type of anti cavitation SCA) has test strips to tell the concentration of the SCA charge.  The strips come with a color chart on the package and they are easy to use.  Simply dip the test strip into a sample of the coolant you want to test and compare the strip's colors to the chart.  The FleetGuard strips show freeze point and pH level as well as the SCA concentration.  FleetGuard also is the maker of precharged coolant filters with precharges varying from 4 units to ?? ( i never checked how high they went, a T444E, or PowerStroke uses a 4 unit filter)  I buy the test strips, DCA4 additive and filters from the local Navistar dealer here in Dayton.
 

blueblood

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Steve said:
We hear about preventing engine cavitation in the cooling system of Cummins and other wet sleeve engines, but what are the signs of cavitation...how does one know there is a problem?

Cavitation drills holes throught the sleeves wall. Therefore, you'll know you have aproblem if -you have coolant in the oil when the engine is off and oil in the coolant when its running.
 

blueblood

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Ron from Big D said:
Steve:

? ? ? I don't think there is any real symptoms except excessive pinging or pre-ignition.? And of course, all diesels rely on compression ignition, so it's difficult to know the difference.? You will sure know when it has occurred because you will have coolant in your oil.? At that point, you have an engine re-build facing you.

Pinging etc is not the same as cavitation and wouldn't be an indicator. Cavitation is the natural result of sleeves being moved by the slapping of pistons on each stroke, thus moving them away from coolant and creating air bubbles that explode at surface of sleeve and eats away material until finally a hole is eaten through the sleeve and allowing movement of coolant.
 

Ron

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Basically there are no operational symptoms of cavitatation untill its too late and very expensive. :'( :'(  The only way to avoid problems is by testing for proper SCA content in the coolant.
 

thenosyone

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AS far as my knowledge... Blueblood is absolutely right on this matter.
Can you explain me how chemicals can prevent this to happen?
 

BernieD

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thenosyone said:
AS far as my knowledge... Blueblood is absolutely right on this matter.
Can you explain me how chemicals can prevent this to happen?

My understanding is that the chemicals react with the bubbles and disolve them. That eliminates the problem of the bubbles exploding.
 
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