Would somebody please explain to me what cavitation is and what the symptoms are. I have gathered that it has something to do with cooling system. It sounds bad. Thanks guys

 

as i understand it on the 6.9 and 7.3 eng its when an air bubble forms on the cylinder wall on the water side the spot will start to glow red hot and ahole will start then water ethier comes in the cyl or you put pressure into the cooling system
symptoms would be overheating steam in the exh or piston or rod out the side of the block
all is bad
overheating and steamy ex could also be a blown head gasket
good luck
butch

 

The symtoms I have seen start with loosing coolant and end with engine locking up on the starter from hydrolock.

 

Cavitation is little bubbles on the cylinder walls on the coolant side.
The vibration from the combustion of the fuel is where the little bubbles come from.
The little bubbles start to corrode (rust) little cavities in the cylinder walls.
Once little Cavities form, this is the most likely place for the bubbles to form next time, so the process continues in the same places.
The little cavities just keep getting deeper and deeper till the are all the way through the cylinder wall.

Then the coolant does what Spectramac said.

 

Well, it looks as though I could have made a big mistake. I just bought a '93 F-250 w/ a 7.3 dsl. I have never owned a dsl before and now am learning some things I should have learned before the purchase.

The truck runs fine, looks great too..(160K miles) But after reading this forum for a while I am a little scared.... When I bought the truck it was low on coolant... Though the truck was sitting a good while before I bought it, I am wondering now if it has wholes in the cylinder walls caused by cavitation.. *****... I guess time will tell ; if I have to add coolant again soon, then I'll know for sure huh?

Is there any other indication that there is a problem? I don't really see any white smoke in the exhaust.. Should I look for some specific residue? ..or listen for certain noises? or.. ?

How long does she have to live? How many $$thousands$$ to fix this?

ouch..

 

Rust has nothing (or very very little) to do with cavitation. Vibration causes air bubbles to form and bounce against the cylinder walls and basically pummel the material away. It is a mechanical erosion of material, NOT corrosion, so if the motor is sitting a long time without running, it won't be any more cavitated than it was when it was parked. It has to be running to develop the vibrations and air bubble erosion. The air bubbles don't just sit there and get hot. If your cylinder walls develop holes,... when you shut off the engine, water will seep into the oil, and the combustion chamber, and eventually your engine will not start. All you can do now is run the right coolant additives and drive it, if the engine does fail, then it will be a costly rebuild, but no more than if you rebuild before it fails. Failures are very rare, but do happen.

 

Al V, Thanks for the reply.. I'll watch the coolant levels closely, and check the SCA stuff right away.. By the way, by mentioning the time the truck was sitting not being used I was kind of hoping that some of the coolant had "evaporated" over that time, perhaps through a loose radiator cap, etc.. Wasn't really concerned about rust... I understand the process of cavitation...(a physical process /not chemical) ...

You said "Failures are very rare, but do happen."

So, maybe my "new-to-me" truck has longer to live than I thought.. hoping so..
Thanks again.
Anyone else want to try to cheer me up? he he

 

There are addatives you add to the coolant to prevent this. The ones with this problem are the ones with out the addative in them.

You run a low silicate heavy duty antifreeze and a Supplamental Coolant Addative (SCA)
Never run the green Prestone stuff or another regular auto antifreeze.

I run Ford Heavy Duty antifreeze and SCA.

If it cavitates, you are looking at a complete rebuild, bunches of $$$$ ( read as dollar signs to the 4th place left of decimal)

To do a complete change you need 4 gallons of antifreeze (VC-7A) and 2 bottles of (VC-8) SCA (Ford part numbers)

Flush the cooling system out several times, the two antifreezes (regular auto and heavy duty diesel) are not compatible.

Ford also sells test strips to test for proper levels of SCA's that will tell you if the addatives were used in the cooling system before you added what ever you added.

You must test the antifreeze every couple of months to make sure you have the proper level of addative in it. To much is just as bad as not enough.

I personally check it every other month.

If you smell the sweet smel of antifreeze in the exhaust pipe, that is bad, but it could be a head gasket leaking. That is still not good, but it is lots better than cavitation. Hoses, heater cores, soft plugs, block heaters, water pumps and oil coolers are also possible culprits for leaks.

Don't jump ship just yet, you may be just fine. First you need to check for SCA's and find out if you have a leak or not. Also if you added regular antifreeze you need it out and a good heavy duty antifreeze with addatives back in, tomorrow is not to soon if you possibly can.

 

Thanks Dave! Tomorrow the old antifreeze comes out!

I'll stop by on the way home from the fire station and pick up the items I need.. I'll have to drive her 15 more miles with whatever is in the radiator..
Also, regarding the exhaust smell, when I started it tonight, here at the station, I tried to smell for coolant in the exhaust.. couldn't really smell it, but the diesel smell is pretty overpowering.. maybe it'll take me a little time to be able to discern that..

The guy I bought the truck from is pretty good guy.. he said he hadn't had any problems with the truck.. I'll ask him about "SCA's"..
So, It is beginning to sound like even trucks with small 'pinholes' in the block may be able to drive for a good while before the engine completely fails? Still hoping mine is not leaking though..

 

When it starts leaking due to cavitation you do not go far.
You can run for a long time if you let it run all the time, but when you turn it off the pressure in the radiator fills the cylinder with antifreeze.
When you try to start it the antifreeze does not compress, you hydrolock the engine and there it sits.
If it will not crank, starts to crank but stops like it has a bolt in the cylinder, do not try to crank it or pull it. You will break something you do not want to pay for.
You can pull the glow plugs all out and antifreeze will blow out of one of them. That is the cavitated cylinder or the one with the blown head gasket. After the antifreeze is blown out you can reinstall them and it will run to drive it to a garage close by, take the radiator cap loose as soon as you turn it off, then they can probably start it again to get it inside.

If he ran SCA's in it you should have 1 to 2 hunderd thousand miles left on that motor easy.
Change the oil like clock work, that is the key to long life. Use a good diesel oil, I would try to run what the previous owner did.

 

Well, today I flushed the coolant system. Added the correct amount of Heavy Duty Coolant and Supp.Coolant Additive. I also spoke with the previous owner... He did know what "cavitation" was and knew of "SCA's." He said the owner before him took perfect care of the engine. I get the impression that the guy I bought it from probably used SCA's but didn't check the levels very often, if at all... But some use and his knowledge of it made me feel a little better. He assured me that the motor is in great shape..
I ran the truck today at least 75 miles, and with several starts/stops. One stop lasted over two hours.. Each time the truck started with no problems. I am beginning to think I may not have damage from cavitation, but I will be watching the coolant level closely.. Next issue/project: checking the glow plug system as it doesn't start well in the cooler mornings.. but that is on another thread..

THANKS FOR EVERYONE'S HELP! This forum is great.... I really like the truck.. I am hooked on this big truck/diesel thing!

Wesley
93 F-250 XL, 7.3 IDI, 4x4 Ext Cab, with 4" superlift and 33 x 16 tires/wheels.
Pure fun to drive..

 

I took the following statement to heart "To do a complete change you need 4 gallons of antifreeze (VC-7A) and 2 bottles of (VC-8) SCA (Ford part numbers)"... and went down to the Ford dealer and they were NO help. They didn't carry SCA test strips, and didn't recommend the antifreeze (VC-7a) or the additive (VC-8) for a 1990 7.3L.
I'm sure this parts man was no diesel owner and was going by the parts recommended in his computer, but I'm needing some reassurance that this additive is needed for the older diesels and that we aren't talking about Powerstroke's here.

 

It is needed for all diesels, and I have even gotten the same reaction at an International dealer, I said cavitation, and he said "cava-who?"

Most Ford dealers are clueless.

Go to a Big Truck supply house.

 

I worked on John Deere for 20+ years, most John Deere Ag dealers will also have "coolant conditioner" additive that Deere uses to help with cavitation.

 

http://www.shopdiesel.com/index.cfm/...egory_id/3.htm

Everything for your cooling system does exist.

And a story

I am an owner of a 1989 Ford F350 PU that has a 7.3 Liter Diesel Engine...or should I say had. After 108,000.00 miles, my motor developed pin holes in the block which caused major damage. I serviced the truck, including changing the coolant, and maintained detailed and accurate records. However, this did not help because I never added a coolant conditioner which is very important in diesel engines. Ford does not even mention this conditioner in their maintenance guide! And to make matters worse, two local Ford dealerships which serviced my truck in the past said they never heard of this problem. I now have a truck that is useless. After calling Ford and informing them of the problem I was told that the truck is out of warranty, which doesn't help me one bit.