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Cavitation ruining a head? wtf?

Discussion in 'The Garage' started by sled_dog, Jan 8, 2006.

  1. sled_dog

    sled_dog 1 ton status

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    A buddy of mine works in a truck garage at a local dealership(big rigs, tri-axles, buses, and fleet pickups mostly). One guy had a 1994 Chevy 2500 4x4 with a 6.5TD. It needed head gaskets. They pulled the head and had found the coolant had "Cavitated" and worn the head so they felt it was junk and needed a new motor. So they parked it outside and there it sits now. He thinks I can pick it up for like between 2-3000. Bluebook is 6 something and it has a REALLY nice utility body I could sell for a good junk of change. But wtf do they mean by this cavitating? I picture mixing and swirling water, did it like sandblast the head? There seems to be scratches there they tried to clean the head up with like a grinder... my thought is just deck the heads a bit and throw them back on. One 6.5 expert in their garage said it would be an easy fix and has no idea why they are junking the truck. I really want a Diesel Chevy(so I can swap a 12V in it without emissions hassle), and a 4x4 since my tow rig now is 2wd. Anyone help me figure this out?
     
  2. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    Coolant in diesels, thanks to high cylinder pressure, expands around the bores (and various areas in the heads) under compression stroke and forms bubbles. When the pressure is released, the bore shrinks and leaves a vacuum when the bubble pops, the coolant rushes in to fill the area and hits the bore/head. Do that millions of times, and it pits out the areas, sometimes eating all the way through. I've seen liners with holes in them from that...haven't seen any heads do it, but it has happened before. It happens from a lack of SCA and various other additives. If one of you gets it, you can't really just clean it up if it is bad. Whatever you do, it is best to add a bottle of Pentcool. Pentcool is the additive that prevents cavitation...or even better...buy Detroit Diesel coolant from a semi-truck dealer. It is already pre-charged with the stuff and you just mix it 50/50 with water.
     
  3. sled_dog

    sled_dog 1 ton status

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    thanks, I will take a really good look at it before I get it, if I do. Have to sell my present truck first.
     
  4. DieselDan

    DieselDan 1/2 ton status

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    That's kinda weird. 6.5s (& 6.2s) are not known for having cavitation problems. I heard Powersmokes have had issues with cavitation.

    I would try to get it cheap. Betting on the fact it was mis-diagnosed (or they're calling a warped head a cavitation problem :rolleyes: ). Pull the heads, take them to a machine shop.
     
  5. sled_dog

    sled_dog 1 ton status

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    thanks guys, when we looked at the head my buddy said himself "huh I can't see wtf they are talking about(no pitting on the head)". Haven't seen the engine yet, hopefully he can work a really good deal for me. As it sits it is just going to the junkyard, and its in way too good a condition for that. Even has a 14 bolt Full Floater in it :D
     
  6. 6.2puller

    6.2puller 1/2 ton status

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    I will second that. This is much more common on Fords. GM usually has more trouble with head gaskets and ford has the cavitation issues in my experience. Not to say it can't happen on the 6.5 just not common.
     
  7. 1979jimmy350

    1979jimmy350 1/2 ton status

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    what type of coolant were they running in it? Was it the green or dexicool. If it was green i would look at the engine real well gm switched to dexicool because of cavation problems. the dexicool protects better than normal coolant against cavation
     

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