Coolant replace

[dmaxstu]

Once in the past I dealt with an aluminum head engine which developed electrolysis which bored a hole from the cooling jacket to the combustion chamber. I was told that the cooling system had not been serviced properly and by changing coolant on a regular basis would have prevented this problem.
So with this in mind I decided to have the coolant changed in my Duramax at 40,000 miles instead of the recommended 150,000 miles. Well the service writer told me that I was very wise since folks who do the 5yr. 150,000 routine have had blocked radiators since the Dex-cool gells as it ages. I was surprised they would even own up to such a fact.
I would like to hear the consenses on this board regarding coolant issues. Stu

[oyazi]

I've heard F*rd had the problem of cavitation pitting/holes thru to the combustion chamber and required a special additive to be placed in the coolent to prevent it. I've not heard of such a problem w/ours ~ or any others except the F*rds for that matter.
I would expect the dealer would have more business w/more frequent changes but I too would look to changing out before the recommended time also.

[jbplock]

I still like to change the coolant annually… I flush with distilled water and add fresh Dexcool. It’s also not hard to do yourself … Some of us have even also added Coolant Filters. :eek: The following threads contain more info on this subject.

How often do you change coolant (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=3;t=007397)

Changing the antifreeze (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=3;t=006908)

Coolant Filters (http://forum.thedieselpage.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=006730#000003)

There was also a good Diesel Page article on Dexcool last year (now available in the 2003 Feature Articles & Product Reviews (http://www.thedieselpage.com/back03.htm))

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[BradL]

My '01 is now 4 1/2 yrs old and has 80,000 miles on the clock, so it's due for the coolant change. For you guys doing the coolant change, are you also replacing the hoses? I'm actually more worried about the hoses than the coolant.

A quick quote from the dealer was $450 to replace hoses and coolant, so this will be another shadetree mechanic job.

[Craig M]

Full size Cummins engines (220 et al) have had the electrolisis (sp) issues in the past.

[More Power]

Havoline considers Dex good for 250K, but the auto industry is a little more cautious, which recommends 150K.

Personally, I'm not at all worried about Dex - even for extended+ drain intervals. Unless... a problem develops with the engine that produces an air pocket inside the engine or radiator. The experts have concluded that an air/coolant interface can produce a potential for corrosion. GM's mid-size gas engines suffered from this well documented problem. The coolant air-bleed screw may not have been at a high point in the system.

To date, I've not heard or read of a corrosion problem in a 6.5 or a Duramax. The 6.5's got Dex beginning in the 1996 model year. Given the propensity for owners to neglect the cooling system, I've still not heard of a corrosion problem in any GM diesel engine. We have a 6.5 with Dex and 160K+ miles. No problem...

The lower rad hose is about $130 all by itself. Generally, the top hose is the one that sees the highest temperatures and is the first to fail. I'd be inclined to not change the lower hose.

MP

[BradL]

MP,

I agree with you thus far on the dex cool. Since I'm well within the mileage recommendation, 80,000 vs the 150,000, I'm more concerned about the time recommendation, 4.5 years vs the 5 years?

My local Chevy dealer service writer tells me that the hoses are generally good for 6-7 years, that they rarely do any replacements due to failures these days.

Because I deer hunt in Mexico, I can't afford a breakdown across the border.

[BigO]

You have multiple choices on this subject. You can purchase the hoses and just keep them in the truck or you can just change them.

I do not agrre with just changing the upper. They all carry fluid through them and it is possible for either one of them to blow. Understnd a hose fails from inside to outside. If the hose is hard or crunchy then that is a sign of age and failure can occur, if the diameter is enlarged this can tell you that it is getting week.

REMEMBER If you change one hose, change them all. You would not want to get stranded because a molded heater hose let go. These are a small diameter hoses.

Check with your local parts store and see if any of the the big three aftermarket rubber companies are producing hoses yet. As of now Goodyear does not.

[Kennedy]

I too will agree that Dex-Cool has been excellent for the GM diesels. Now some gas engines have had MAJOR issues. It is when air (leaks) is allowed to interface with the coolant that problems seem to occur.

I did a simple hose-slip thermostat change on my '96 once. I did not wash the outlet or the inside of the hose. Next time (year or so) that I was there in I found the housing to have a lot of corrosion that was not there prior to this project.

[madmatt]

the 3.1s and 3.4s were/are really hard on coolant due to the leak prone lower intakes. oher then that the dexcool has been pretty good to GM and the consumers.

[k1rod]

Has anybody tried using VW G12 in the Duramax? This stuff seems almost ageless. I have some in my VW that is 5 years old and it is just as crystal clear as new would be.