I had the motor swapped in my 03 Buick century and just noticed that the mechanic drained the old coolant and filled it with green coolant. The manual calls for dex cool. Should I drain and fill with dex cool or am I ok with the green coolant.

Most any coolant will be fine. IF it truly is "green" coolant then the biggest thing is shorten your drain intervals to 2-3 years and approx 30-50k miles- down from the much longer Dex recommendations.

Now... it may not be just "green" as many shops will use some type generic all makes type coolant which may have a totally different and pack than "green" and therefor not mix well with other coolant brands or types. It would be wise of you to find out what the shop used if you anticipate having to add coolant or if you plan to do drain and fills as part of your regular maintenance.

It most likely is a universal coolant. Those are a Dexclone. Same as Dexcool but different dye.

If it is old school conventional greeen he did you a favor.

If it was flushed beforehand, it'll be just fine; if it's just drained and filled then it's likely to be just fine too. There are two main types of 'green' coolant, and you shouldn't only go by color anyway. The old conventional type (90s formulation) has a shorter service life but I'm confident that he put in the prolific Any Make/Any Model-type long life antifreeze. They're usually called Dexclone antifreeze because it has the same active additives as Dexcool, just maybe slightly different in concentration or maybe to avoid the GM licensing.

Oh it is VERY green indeed. I'll give the mechanic a call and see what he put in it

They did the same thing to my Buick when I replaced the engine, he used conventional green. I ran it for a little bit before flushing it throughly and now I run Zerex G05

Color only means its not plain water. I would have asked the mechanic before posting.

Either way, I would flush it after about 2 years, then go back w Dexcool and distilled 50/50

I do plan on flushing it and going back to the 50/50 dex cool formula

Before you flush it out, I would go back to the mechanic and ask him what specifically he put in.

I say this because if he used anything like the current Prestone/Peak/WalMart/etc.. "Universal antifreeze/coolant" - which is a bright green - then it is, for all intents and purposes, a "clone" of dexcool.. or a "dex-clone". It may look the same as the old-school 'conventional' stuff, but it's not.

If this is what the mechanic put in, then I'd say you're good, at least for a couple years.

I would bet he used a Prestone like antifreeze that is good for 5 years/150K miles... Conventional green coolant usually only goes in cars made 1995 or before.

Wrong wrong wrong....

The OAC EG coolants have about 15% better thermal transmissivity than the old green EG formulations...
Going backwards to Green actually results in a slight net LOSS in cooling performance.

The green is better myth really needs to stop.


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A lot of the coolants you get today are a sort of "hybrid" coolant that use both the newer organic additives in addition to older types.

I think the main thing to figure out is whether the Dexcool has silicates, nitrates, phosphates & amines (I think thats the main set) and match whatever you put in with those.

Loss of coolant heat transfer capacity may or may not be a problem .

Are you in a hot climate + use A/C a lot ?

Is radiator air flow good or is it stopped up with bugs / debris ?

Mostly highway driving or mostly city stop and go .

Are the tubes / tank of the radiator clean or stopped up enough to diminish coolant flow / heat transfer ?

Cooling fan / fans operating properly ? Water pump working properly ? Hoses not kinked / collapsing ?

Block / heads clean / clear or are they stopped up ?

I gave run 100% AF coolant for years . I have been flamed numerous times , " 50/50% cools better than 100% ! " . Probably so . But I mainttain , if there is no water in the system , no rust .

Only time I have had heating problems is if a leak developed . And we had a 100F day earlier in the week . Currently 94L & sunny .

God bless
Wyr

What are some of the different brand names of Dexclones ? Are they OK to mix with Dexcool ?

Thanks , :-)