GM's 5yr or 150,000 mile coolant change

[Rat407]

How important is it do follow this rule? Considering the miles are not adding up but I'm at 5yrs is it wise to get this accomplished? Anyway to test the coolant to see if it is bad or is it more on the lines of the buildup inside the system that needs to be flushed out?

 

[millerbl00]

Very important. Dexcool over a certain age can harm head gaskets and water pumps. Change it....

 

[zrxkawboy]

IMO it is much more important to change coolant based on time than miles.

 

[SirTanon]

Originally Posted by Rat407
How important is it do follow this rule? Considering the miles are not adding up but I'm at 5yrs is it wise to get this accomplished? Anyway to test the coolant to see if it is bad or is it more on the lines of the buildup inside the system that needs to be flushed out?


If you hit 5 years, but still haven't hit the 150,000 miles, you still need to change out the coolant. That's what the "5yrs OR 150,000 miles" means. Whichever comes first.

 

[Propflux01]

Just remember to read on alittle further in that manual, which usually states to "from then on, change every two years or 30,000 miles". Funny how it can go from lasting 5/150k to 2/30k and the fluid is identical.

 

[SirTanon]

Originally Posted by Propflux01
Just remember to read on alittle further in that manual, which usually states to "from then on, change every two years or 30,000 miles". Funny how it can go from lasting 5/150k to 2/30k and the fluid is identical.

I'm pretty sure this is based upon the assumption that people will put the wrong stuff in. When mixing "universal coolant" (Read as "incompatible chemistries"), it's generally accepted that, even if both on their own are "long-life" or "super long-life", the resultant mixture is only really good for (at most) 2 years/30,000 miles.

Thus, if I mix G-05 coolant (5 years / 100,000 miles) with Supertech "All Makes, All models" coolant (5 years / 150,000 miles), the resultant mixture will only be good for 2 years / 30,000 miles.

 

[Gebo]

Originally Posted by Propflux01
Just remember to read on alittle further in that manual, which usually states to "from then on, change every two years or 30,000 miles". Funny how it can go from lasting 5/150k to 2/30k and the fluid is identical.


I would love to get an answer to this question. I think other cars have similar instructions. Is the factory antifreeze some jacked up product that we can't buy in the stores?

 

[WobblyElvis]

My experience is vehicles since the mid 90's don't need coolant changes more often than every 5 years and then I just drain the rad and change half the fluid . Haven't flushed a radiator since the 80's. Coolant continues to look good and the inside is spotless.

 

[gregk24]

I would change it at least that often. I am not a believer in "lifetime" fluids. I know it says 5 years / 150,000 miles, but thats a lot of miles for the antifreeze to go on one change. Maybe I am old school. I am just of the mindset that fluid is cheap, so changing often is good insurance. In fact, I change the coolant in my Accord every 2 years. It is cheap and super easy to do.

 

[tcp71]

Once it hits a certain age or mileage, i start a drain/fill of the radiator every year with a gallon of original oem coolant. It's not a complete flush, but refreshes continuously, is cheap and it's easy to while the oil is draining.

 

[ls1mike]

Originally Posted by SirTanon
Originally Posted by Propflux01
Just remember to read on alittle further in that manual, which usually states to "from then on, change every two years or 30,000 miles". Funny how it can go from lasting 5/150k to 2/30k and the fluid is identical.

I'm pretty sure this is based upon the assumption that people will put the wrong stuff in. When mixing "universal coolant" (Read as "incompatible chemistries"), it's generally accepted that, even if both on their own are "long-life" or "super long-life", the resultant mixture is only really good for (at most) 2 years/30,000 miles.
.

SirTanon you are correct.
Out of my 2002 2500HD Manual.
Engine Coolant The cooling system in your vehicle is filled with DEX-COOL engine coolant. This coolant is designed to remain in your vehicle for 5 years or 150,000 miles (240 000 km), whichever occurs first, if you add only DEX-COOL extended life coolant.
The following explains your cooling system and how to add coolant when it is low. If you have a problem with engine overheating, see "Engine Overheating" in the Index.
A 50/50 mixture of clean, drinkable water and DEX-COOL coolant will: Give freezing protection down to -34F (-37C). Give boiling protection up to 265F (129C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as they should.
NOTICE:
When adding coolant, it is important that you use only DEX-COOL (silicate-free) coolant. If coolant other than DEX-COOL is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner -- at 30,000 miles (50 000 km) or 24 months, whichever occurs first. Damage caused by the use of coolant other than DEX-COOL is not covered by your new vehicle warranty

From my 2000 WS6 Manual
The cooling system in your vehicle is filled with DEX-COOL engine coolant. This coolant is designed to remain in your vehicle for 5 years or 150,000 miles (240 000 km), whichever occurs first, if you add only DEX-COOL extended life coolant.
The following explains your cooling system and how to add coolant when it is low. If you have a problem with engine overheating or if you need to add coolant to your radiator, see "Engine Overheating" in the Index.
A 50/50 mixture of clean, drinkable water and DEX-COOL coolant will: Give freezing protection down to -34F (-37C). Give boiling protection up to 265F (129C).
Protect against rust and corrosion.
Help keep the proper engine temperature.


Apparently at this point in time GM didn't realize that DEX-COOL would be a problem or they figured people who actually knew something about cars were buying WS6's and didn't need the warning...

 

[ls1mike]

OP change it if it has been 5 years. The DEX-COOL does not cause problems in LS based engine like it did in the 3800, 4.3, 5.7 etc.
You have a dry intake (no coolant or oil touches it). It does not ruin the gaskets in LS engines. I know tons of guys with more miles or time than 5 years running the original coolant in the there LS based stuff.
I always change mine every 5 years in the Truck and Trans Am. No issues. The LS motors...LS1, 4.8, 5.3, 6.0, you get the idea are, are really easy on coolant.

 

[ozric]

Originally Posted by Propflux01
Just remember to read on alittle further in that manual, which usually states to "from then on, change every two years or 30,000 miles". Funny how it can go from lasting 5/150k to 2/30k and the fluid is identical.


Simple really. As an example, my mazda holds about 2 gallons of coolant. A drain gets about 1 gallon out, so after adding a fresh gallon of the mazda premixed 50/50 coolant the system has 50% original coolant and 50% new coolant.

So the time frame for future drains would drop because only half the fluid now has fresh additives. Make sense?

Now if you do a complete flush with the same factory fluid you could leave it in there as long as the factory fill.

 

[SteveSRT8]

Since Dex was introduced we have only serviced cooling systems as needed. So that meant at least 100-150k miles when a water pump leaked or a 'stat was erratic. Sometimes more.

Never a spot of corrosion, Dex is great stuff for us...

 

[bradepb]

We have about 20 GMC 3500 chassis with 6.6L Diesel and we only change Dexcool if something leaks it out.
Ours are mostly 2007 and 2009. Most with well over 100,000 miles.

 

[Leo99]

I think you should follow the recommendations in the manual and hope for the best. No need for a lot of thinking about it.

 

[loneryder]

My MB ML says 5yr/150k change interval. Mine has been well over 5 yrs. I asked my Indy about it and he said don't worry about it. Just test it every year. The difference might be that MB has a block of additives in the overflow tank that slowly dissolves over the years to replentish the additives. He said no need to replace it until I need to do a repair to the cooling system.

 

[dogememe]

Originally Posted by loneryder
My MB ML says 5yr/150k change interval. Mine has been well over 5 yrs. I asked my Indy about it and he said don't worry about it. Just test it every year. The difference might be that MB has a block of additives in the overflow tank that slowly dissolves over the years to replentish the additives. He said no need to replace it until I need to do a repair to the cooling system.

For real? What if you replace the coolant tank? That's bizarre!

 

[dogememe]

Originally Posted by loneryder
My MB ML says 5yr/150k change interval. Mine has been well over 5 yrs. I asked my Indy about it and he said don't worry about it. Just test it every year. The difference might be that MB has a block of additives in the overflow tank that slowly dissolves over the years to replentish the additives. He said no need to replace it until I need to do a repair to the cooling system.

For real? What if you replace the coolant tank? That's bizarre!

 

[StevieC]

Originally Posted by Rat407
How important is it do follow this rule? Considering the miles are not adding up but I'm at 5yrs is it wise to get this accomplished? Anyway to test the coolant to see if it is bad or is it more on the lines of the buildup inside the system that needs to be flushed out?


I'm a big proponent of changing the coolant at 1/2 the time and interval by doing a spill/fill of the radiator that way there is always fresh-ish coolant in the system and a complete drain and fill isn't necessary.
It has never has failed me and I typically drive my vehicles to the scrap yard tons of miles later with original cooling system components intact. (Like my Santa fe with original water pump (timing belt driven) and radiator)

My advice is that if you are at the time or mileage component I would change it out, especially with Dexcool and do a complete drain and refill. If you were at 1/2 the mileage or time I would just do a spill/fill of the radiator.