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Antifreeze question?

Crankme69

Crankme69

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For the years prior to my introduction to this forum and my 6.5TD I was running my old 7.3 1990 N/A INI diesel. Maintaining the antifreeze PH and assuring no cavitation was IMO one of the reasons my old 7.3 is still running now at 332K on the clock. Here is one article that provides some cavitation and PH stats pertaining to the 7.3 INI diesel. http://www.expertdiesel.com/cavitation.htm

Question do our 6.5's have the same issues? I added a bottle of Lucas antifreeze wetter to my coolant right after I purchased it last Oct. Is there an AC delco additive also or? Should we be checking the PH in our 6.5's?

In my Ford 7.3 I always spent the money on the OEM antifreeze additive, kinda pricey like 18 bucs a bottle & I always added 2 when changing the coolant...don't know if it was worth it, but it's still going strong.

Let's hear it...
 
Been running DEX-COOL in mine since owning them, the truck is @ 194K same engine-rad in it so I'm thinking if it has all problems some report they are overblown out of proportion, my burb also running Dex 160K on it
 
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The OP has a 95, so it uses the older green stuff. I personally like ZEREX anti-freeze, but I've only found it at NAPA. The 6.5's don't have the cavitation issues in them that the early 7.3's had though. Whatever you do though, don't run the PRESTONE universal.
 
My current antifreeze selection is the premix 50/50 from wallmart, I run it in everything I own with a coolant additive. I have not changed the mix yet in my 6.5.

The 7.3 INI is the only player that gets the specific additive for the coolant from the stealer.

What is the issue with the Prestone?
 
THEFERMANATOR said:
The OP has a 95, so it uses the older green stuff. I personally like ZEREX anti-freeze, but I've only found it at NAPA. The 6.5's don't have the cavitation issues in them that the early 7.3's had though. Whatever you do though, don't run the PRESTONE universal.
Click to expand...

Our 1995 Suburban came from the factory with Dex Cool. Never had a problem with it. The new engine will get Dex Cool as well.
 
http://www.dexcoolsettlement.com/

I won't use dex cool. I have 2 GM V-6 motors, and one has had intake manifold failure, and the other blown head gaskets. The dex-cool would eat away at the head gasket material and cause problems. maybe it's half coolant and half gasket material I don't know, but it was first proclaimed by GM to be a extended life coolant. So people would run it longer than 2 years, and when it gets old, and contaminated, it gets thicker like mud in some cases. I've seen its bad effects in GM dealers since the late 90's. I'm a lifetime GM guy, But I won't be trusting that stuff in any of my engines. Just my 2 cents.
 
I switched to green last winter during a head repair. Drained what I could, refilled with mixeable green. 15k miles, and one year later no issues.
 
Crankme69 said:
What is the issue with the Prestone?
Click to expand...


The PRESTONE universal stuff provides virtually no rust and corrosion additives in it. I've lost the head gaskets in 2 engines now with that stuff. After 2 years the steel rings in them had rusted through. NEVER had this problem when running ZEREX. I've also had quite a few water pump failures with it after I started ptting it in customers vehicles. I used it for awhile as it was universal and easy to get, but I now keep the 3 major ones in my shop and use the right one for the job.
 
Pruittx2 said:
http://www.dexcoolsettlement.com/

I won't use dex cool. I have 2 GM V-6 motors, and one has had intake manifold failure, and the other blown head gaskets. The dex-cool would eat away at the head gasket material and cause problems. maybe it's half coolant and half gasket material I don't know, but it was first proclaimed by GM to be a extended life coolant. So people would run it longer than 2 years, and when it gets old, and contaminated, it gets thicker like mud in some cases. I've seen its bad effects in GM dealers since the late 90's. I'm a lifetime GM guy, But I won't be trusting that stuff in any of my engines. Just my 2 cents.
Click to expand...

I've also seen this,I will never run dex cool in any of my vehicals either.
 
I hate Dex-cool, not saying it doesnt work for some, but its not as advertised. It does sludge up, seen it in both my Z28 and my 6.5. Neither was overheating but couldnt have been good. Bottom several radiator veins couldnt have been moving any water with the sludge blocking them. Never seen this with the green stuff. Perhaps it happens where you live in a place that never needs antifreeze ;)

Been running a year now with a bottle of water wetter and like 10% Zerex or Peak.
 
Crankme69 said:
Question do our 6.5's have the same issues?

In my Ford 7.3 I always spent the money on the OEM antifreeze additive, kinda pricey like 18 bucs a bottle & I always added 2 when changing the coolant...don't know if it was worth it, but it's still going strong.
Click to expand...
The whole cavitation issue was due to cylinder wall thickness decreasing to the overbore (6.9L to 7.3L). The 6.5 walls are sufficiently thick to prevent that from occurring. Simply not an issue with this motor. For us, the only question we face is what antifreeze/coolant to use. I've used DexCool in four VW diesels, and yes, I've seen the sludge that people describe. I've also read about different reasons/theories why this happens. I've been running DC in my 85 Ford 6.9 for five years now, with no problems. My 94 C3500 6.9 runs the green stuff, also with no problems. The reason I chose the green stuff for the Chevy is because it's cheaper. Both trucks use a 50/50 mix of antifreeze and distilled water. With this mix and a 15# cap, I'm good to 265 on the top end and -20 on the bottom.
 
Thanks for sharing the info.

Interesting enough, I also had dumped the Dex Cool out of a 1996 V-6 3100 back in 2002. That 3100 had the sludge build up, I flushed it and put in fresh green antifreeze...my son who is a mechanic informed me that I had made a grave error...2 weeks later it sucked in the intake gasket and filled the crankcase with the entire coolant content. We changed the intake gaskets and resealed it, flushed both coolant and crankcase & put green back in. It's still running now at about 176K. Not sure if that was just a coincidence or if it was due to the coolant change?

So I'm not too thrilled with the Dex Cool.

My 6.5 coolant looks clean, like all the other fluids in it, I think all the fluids were flushed prior to my purchase and based on the condition they must have been kept clean from the previous owner.

My real concern is if I need to add to my coolant system now on the 6.5...not knowing what is in it currently and skeeerd to hell from my 3100 experience to fudge with it...

PS don't forget to tell your Significant Other "Happy Valentines Day"
 
Threads like this make me overthink about my cooling system which wasn't even in my head, and now I want to flush and refill.
 
Sorry Matt, I do think there are many failures due to high corrosion from failure to change coolant. The stuff just don't last forever.

No Dex Cool here for me, hope I'm not in for any surprises after I change it...:yikes:
 
I know my DMAX that I swapped in had 162K on it and it had probably never had the anti-freeze changed. 162K miles and was roughly 8 years old, yet there wasn't hardly any scale build-up or anything inside of it. The heads looked beautiful when I pulled them down, and the coolant leaks were the turbo hose that fails from heat and the MLS head gasket had just worn through which was common to the early gaskets. I know GM changed the formula for dex-cool in the late 90's or so due to the early problems and the class action lawsuit. I'm currently using the ZEREX DEX-COOL in my BURB now. I figured if the factory stuff worked that well for that long, why not stay with it.
 
My take is doing the work to flush & refill w/ a quality antifreeze/DI or RO water mix on some reasonable interval is probably more important than antifreeze chemistry choice as long as you pick a quality mix.

There may well be long-term differences, but I've had good luck w/ both green & Dex-Cool. Vehicles & machines I've bought new & I've done all the cooling system maintenance over the years have always shown relatively clean/sediment free water galleys when I tear them down to rebuild.

Except for engines prone to specific cavitation or electrolysis issues, the ones I've seen with corrosion issues seemed to be correlated w/ me or a PO not staying on top of maintenance.
 
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