tjdismee

The manual for my 2014 C7 recommends a coolant drain and refill at 5 years or 150,000 miles. The 150,000 miles seems ok, but 5 years seems ridiculous. Especially for a car that spends winters stored. The car is 5 years old with 17,500 miles. Does anyone actually follow this?

joemessman

I thought the same thing, but did some research on some supposedly reputable websites and came to the conclusion that the coolant used in vehicles in this day and age is actually that robust to withstand that many miles. Age seemed to be the most determining factror. Let's read what others say on this topic.

rjacobs

Yes thats a dex-cool recommendation of 5 years.

I thought it was 100k miles or 5 years "in general" for Dex-Cool...

I would dump it...

I dumped 18 year old Dex-Cool out of a 96 I purchased last year. Was a little sludgy, but not as bad as I thought it would be.

trivette

My '14 is the same age and very close mileage to the OP and I've been wondering the same thing. I'm still on the original battery which is another topic but not sure what I should be doing with the coolant at this point.

JerryU

You're changing for corrosion! Car stored or not - corrosion is occurring all the time. The coolant has some anticorrosion additives that deplete in time.

I'll do at ~4 1/2 years like I did in my C6 to avoid having to flush!

It's easy. Remove the bottom plug (pic of C6 below) and let it drain with cap off the fill tank. Took about 30 minutes to get somewhat over 2 gallons. That is about 3/4 of what is in the car. Manual says use flush procedure IF it looks contaminated, dirty. Mine looked fine so was happy adding of 1 gallon new coolant. Bought 100% concentrated GM Dex Cool by Prestone and a gallon of distilled water. Yep leaves some of the original coolant BUT that gallon of new adds the needed additives.

I filled the overflow tank with approximately equal amounts of new coolant then distilled water. Ran the car for 4 minutes and the tank was empty so added more. Repeated until the overflow was at the required level. Ran the car for a few trips and filled to the line. Took about 12 more ounces of the mixture. Use plain water for the final topping off as the manual says use 40% Dex Cool and 60% drinkable water. Considering what was left and the amount drained, that is about where mine was.

Your car do as you wish.

Red86Cfour

I've got what I believe to be the original coolant in my 2000 GMC 2500 Sierra. Its still orange and at the required level, I've never had to add a drop to it in the 15 years I've had it. I hate to change it but suppose I should.....

Avanti

I do my 18 year old C5 every 7 years... I thought that's what it said in the Manual for it, but I may be remembering wrong. It can't hurt to change more often and unless it has changed dramatically since the C5, it's not that big a deal. I did it myself the first couple changes. With the '18 I've a few years yet to figure it out.

Bill Dearborn

YES. I have been following that regimen since I purchased my 97 C5 which was the first car I had that used DexCool. Changed it all other vehicles once every 5 years. My 2003 Tahoe that I purchased in Dec. 2002 has 120K miles on it and is still running the original cooling system hoses. I just had the coolant changed for the third time last year. Had a 2008 Malibu that went thru 2 changes.

DexCool works so much better than the old Green Stuff it is unbelievable until you experience it. No more changing every two years now it is once every 5 years. Sitting through the winter doesn't hurt it. Whether the engine runs or sits corrosion is the same.

Bill

rmorin1249

Are all of the various brands of Dex-Cool compatible and equal in quality? I see lots of brands available or is it best to stick with ACDelco? Thanks.

JerryU

ACDelco does not manufature coolant! I have been buying Prestone for years, it says GM Dex-Cool so it's what I buy and usually cheap enough!

Just a note: If you wait too long to change, you should use the flush procedure. Elaborate if you follow the Service Manual but don't use a flush chemical product as it clearly warns in the Service Manual. If you use the procedure I have used for years of filling with water and draining multiple times until the water comes out clear, be sure only to fill with 1 gallon of 100% Dex-Cool first because 4 or 5 quarts of water will remain. Top off with "drinkable" water, as that will provide a 40% Dex-Cool 60% water mix recommend. Much easier to change at 4 1/2 to 5 years per my post #5!

You car your choice.

Pribilof

Coolant is significantly cheaper than a new radiator. I would change it.

GS583

Does the replacement procedure still call for the "tablets" from GM to be added after the change? That was part of the drill when I changed the coolant in my '96 GS but may have been something they no longer require. It may have been a sealant due to the iron block/aluminum heads on the old LT-4 used in '96.

George_L

Coolant is easy to replace and pretty inexpensive. The Dexcool is only rated for 5 years. I did a tutorial on changing your coolant. You can find it here. Go to post 15.

X25

FYI, my '16 Z51 came from factory at 32% coolant, and '19 Z06 came at 36% coolant. I'm yet to see a C7 from factory with even as much as that recommended amount of coolant. I've set my new coolant at ~30% when I upgraded the radiator, also relying on the fact that Pacific Northwest doesn't ever get too cold.

c6miller

I change the coolant about every three years regardless of milage. It's easy and inexpensive.

JerryU

The C7 Service Manual says nothing about adding a "tablet," nor did my C6!

SIDEBAR
Those tables were probably stop leak materials. Had a funny situation occur when Prestone (a product of our consumer products division) introduced a coolant with stop leak added, recall in our corporate R&D Lab they had a small consumer products group. They were offering to put holes in your rad to test the new coolant with stop leak. They would replace the rad IF there was a problem! Never did it myself but knew folks who did!

We had a new patented machine that automatically welded vertical plate from 5/8 up to 2 inch thick in one pass. It used water cooled copper shoes to retain the molten metal. A shipyard that bought several called as winter approached and asked, "What should we put in the water cooler/circulators?" Just naturally said a 50/50 mixture of Prestone and water. Got a call a few weeks later and was told the water passages in the copper shoes were clogged.

I checked with the Prestone R&D folks and was told it has fine asbestos fibers that would mat together as they went through a hole! It was clogging the small high velocity passages designed into our copper shoes to prevent boiling at hot spots with low water temps!

PS: Don't think you can sue as asbestos is only a hazard if it is breathed. In fact we have Transite water pipe in our Counter Club. Transite is asbestos and clay! Don't recall the number but you can have a very large number of asbestos particles in water and still be safe! Ingesting the "stuff" is not the issue!

However if removing or cutting the pipe it is a hazard! When we just had our dam repaired a section of 6 inch Transite pipe had to be removed. The water company hired a HAMET company! It was replaced with plastic pipe. Transite is no longer used!

C6_Racer_X

Dexcool® does degrade with time. It's the corrosion inhibitors that deplete. It tends to get acidic (low pH) with age, and after 5 years or so it needs to be replaced, no matter how many miles.

If left too long, it gets to "metal dissolving" acid levels, and you generally end up with a leaky heater core. That's a common issue with older GM vehicles (over 10 years old), and neglected Dexcool® coolant is a big contriubtor to that problem.

There are less corrosive coolants and newer coolants that last longer. GM still uses and recommends Dexcool®, and that's actually a decent coolant provided it's checked regularly, replaced at 5 years and not neglected. It also doesn't mix well with air, so any leakage that results in a loss of coolant will cause issues with "sludge" (AKA DexMud) in the cooling system.

Mad*Max

I would change at the 5 year mark and I would just do it myself, cheap insurance. When I sold my 12 year old C6 I was still on the original radiator and the cooling system functioned like s new car.

Vetteman Jack

Yes, I change the coolant in my cars at the recommended intervals. My C7 only has 3900 miles on it but when it hit the 5 year mark, the coolant got changed.

Crossed Flags Fan

Did mine today. EZ PZ. Thanks for the info.