Engine cavitation in ISB

[SilverFox]

After spending the last 5 years in a PS I stopped by the dealer yesterday to pick up some anti-cavitation additive for the Cummins. The parts man didn't know what I was talking about. Said I didn't need anything like that. I've been such a believer for so long, even add it to the diesel engines in my tractor and welder, that I still feel like I need the additive just to be safe.



Today I ran a search on "cavitation" and sure 'nough it seems most think an additive is not needed. I haven't noticed this topic being discussed in the third generation forum so thought I would start a thread to see what I could learn.



In case anyone doesn't know what "cavitation" is, it's the action of the coolant being pushed away from the outside of the cylinder wall when the piston moves up and down in the cylinder. It seems the cylinder wall expands and retracts very quickly. The water is pushed away from the wall and comes crashing back with such force that it starts to erode the metal making it porous and eventually causing it to seep into the cylinder and crankcase. There is no fix except replacing the block.



In a PS this can happen in as little as 100000 miles. I've been told the additive makes the water slicker and allows it to stay in contact with the cylinder wall. As far as I know, all large sleeved diesel engines use an anti-cavitation additive, usually added through the water filter.



What I'd like to know is, how many are using an anti-cavitation additive and what information are you basing your use on.

 

[dieselpilot1969]

do you mean like water wetter?

 

[SilverFox]

Never heard the additive called that but suppose that is what it does??

 

[Steve M]

Welcome to the world of Cummins ownership. Forget about the additive. It's not needed with the Cummins. If that's not comforting enough, look at the water pump. Two 10mm bolts and it's out. Try that with a PSD.

 

[rrausch]

There was an article in the TDR magazine a few years ago that cavitation erosion is just not a problem with the Cummins. Cummins Mid-range Engine plant seems to agree. Whether this is due to superior engineering or just plain good luck I've never been able to figure out, but I don't worry about it.

 

[Kel]

Are you talking about the coolant additive?



This is needed on all engines with liners. The Cummins B engines do not have liners. I believe the power stroke does have liners and therefore needs the additive.



Other Cummins engines with liners (C,N,M,X,etc. ) will need some type of coolant additive.

 

[SilverFox]

The Power Stroke 7. 3L is the same as the Cummins ISB, no sleeves.

 

[dieselpilot1969]

water wetter is i think sold or made by Redline, not 100 % sure though

 

[dieselpilot1969]

yup just checked it is redline, about 8 bucks a bottle

 

[dieselpilot1969]

thats strange, what happend to truck info on my 2 last posts?

 

[SRadke]

It only shows in the first post you make on a page.

-Scott

 

[SilverFox]

Went to the Red Line web site and water wetter is nothing more than a corrosion inhibitor and is supposed to increase cooling efficiency. It does nothing to stop cavitation. I guess we don't have a cavitation problem with the ISB. I'm still slightly uneasy, since I've been using a preventive for so long.

 

[abledog]

The ISB's in our trucks don't require anything other than normal antifreeze. The ISC in my motorhome is a totally different animal. The water chemistry for larger sleeved diesel engines is critical and must be maintained.

This is accomplished by either sampling and adding additional chemicals or in the case of the ISC this is accomplished by changing the coolant filter that have the necessary replenishment chemicals in the filter.



Terry

 

[ttreibel]

Cummins recommends just draining the coolant every 2 years and refill with 50/50 regardless of the mileage. I suppose if you drive 50K+ a year you should probably do it yearly.

 

[Dean Upson]

Here are a couple of quotes from the Cummins website that pertain to this topic:



"Supplemental coolant additives work by becoming a sacrificial coating after adhering to freshly exposed liner and block surfaces that are subjected to cavitation. Cavitation is the driving force responsible for pitting damage. It is caused by the formation and collapse of vapor bubbles created during liner movement following combustion. Vapor bubbles are formed any time the localized pressure of the coolant drops below the vapor pressure of the coolant. Vapor pressure is a physical characteristic of the coolant that is primarily controlled by the antifreeze to water ratio and coolant temperature. The localized pressure is a function of many factors including engine design, load factor, piston slap, engine timing, and cooling system pressure. "



And:





"We do not recommend an additive for the B5. 9L engine. The coolant additive is necessary to protect liners from cavitation and the B5. 9L does not have liners; it is a one-piece block. Since the B5. 9L has no liners, it does not require an additive. "



I remember reading somewhere that Cummins has some kind of patent on the cylinder construction having to do with the cavitation issue. The information showed a cross section of the block. Does anyone else remember this?



Dean

 

[FFutch]

The 7. 3 PSD needed it because of a design flaw in their parent bore(no liners) block. The 5. 9 is also a parent bore but needs no additive. There are several million mile 5. 9s out there with no additive so I think most of us don't need to worry. All engines with liners need additive. I've seen Cats and Cummins eat through the liners with as little as 100k. On the other end of the spectrum if you over-treat coolant it will eat water pump seals and cause other problems... Doug

 

[ssanders60]

Cavitation caused by electrolysis (static electricity)

I was told by specialists that the pitting

or cavitation is caused by eletrolysis or

static electricity setting up in the water

jacket on engines with "wet liners" or sleeves.

A certain vibration occurs here in engines

with "wet liners" that may not occur in engines

such as the navistar 7. 3 or 5. 9 L cummins,

except that the cylinder walls on the 7. 3 are

so thin that the electrolyis sets up and prevails

resulting in the pitting. The pitting appears

as though someone took a welding rod and arked

the water jacket side of the liner with the

welding rod, eventually a pin hole developes in

the cylinder and leaks small amounts of water

into the cylinder and blocks the engine from

turning as the case with my nephew's Ford 250

7. 3 diesel with only 120,000 miles. He repaired

this engine by boring and putting in sleeves

and then the use of a coolant with a compound

that prevents electrolysis. Although an engine such as the 5. 9L does not have liners,

a coolant with this protection would surely

not harm or serve as a detriment to the long

service these engines are reputed to have. John

Deere's COOL-GARD coolant that has additives to

prevent cavitation, corrosion, foaming, and

radiator plugging, is a quality and dependable

product. Iwas also told that the Ford or

Navistar 6. 9 has much thicker cylinder walls than

the 7. 3, apparently boring of the cylinder walls

on the 6. 9 created the 7. 3 in addition to other

modifications of the 6. 9L, although I can't be

sure of this.

 

[SilverFox]

I'd like to know if the Cat 3126 7. 2L is sleeved. I don't think it is but am not sure about this. I'd also like to know if Cat recommends an anti-cavitation additive for this engine if it is not sleeved. I'm sure the additive is recommended if it is sleeved. The T-444 7. 3L Navistar engine used in the Ford PS requires 4 pints of FW-16 anytime the antifreeze is changed and the owners manual says to add an additional 8 ounces of FW-16 every 15000 miles. I did this religiously with my '99 and sold it at 117000 miles, never an engine related problem.



If the Cat 3126 engine isn't sleeved and Cat recommends the additive then the Cummins ISB is the only engine I know of that doesn't need the additive. Are we really that lucky... Every year they up the HP and torque. At some point, I believe we'll need the additive. Will it be at 305HP 555 torque or will it be at the next power increase or perhaps never...



I've got 20100 miles on my truck now and am having a hard time not adding just a little of the FW-16 I have on hand. Maybe just 4 oz.

 

[FFutch]

No,the 3116/3126 Cats are also parent bore blocks(no liners). Cat wants their extended life coolant used in all of their engines,irregardless. This stuff is pre-mixed with the additive,but on the older 7. 2's, I don't recall them requiring DCA's. I'll check... Doug

 

[SilverFox]

FFutch, Thanks for the info. I'm going to add just a little FW-16 to my coolant tomorrow. Can't see how it can hurt anything. I have it on hand and hate to see it go to waste.



BTW, if the older 7. 2 didn't need the additive it could be because they didn't know it until it had been in service for several years.