Green Anitfreeze mixed with Dextron - Grand AM

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cardinal43

Member
My GF has a 99 Grand AM with 110,000 miles. Last summer it needed anitfreeze, so I dumped in 50/50 green antifreeze. I didn't realize Dextron that it called for was any different from green antifreeze. I was recently at a Jiffy Lube and they told me that I am seriously damaging the radiator / pumps / cooling system by keeping the green antifreeze in there. (I am always skeptical of their advice)

The coolant is running low, so should I just add Dextron on top of the old green antifreeze from the summer?

Should I pay Jiffy Lube the $120 they want to flush the cooling system?

This car is old, but I'd like my GF to get as many miles as possible out of it.....
 
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dmsrx

Member
If you still have the jug from the green 50/50 you used look on the label to see if it is compatible. Everything I buy it is clearly labeled now and it all says it is okay to mix. I do mix it and haven't had any issues.
 
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mn_mxz

Member
I would not worry about mixing. Most of the antifreeze that they sell now can be mixed. My 2001 Grand Am Gt has 215,000 miles on it and I have not had an issue due to antifreeze.
 
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sjshaner

New member
If you mix the older type green anti-freeze with the orange dexcool then the antifreeze begins to gell up and clog the radiator and heater core. I know from personal experience. There is newer type green antifreeze on the market that is 100% compatible with both types of antifreeze. It will state it right on the bottle. If you used the newer type you are ok. If your car hasn't started overheating and/or not blowing any heat, then you probably used the newer antifreeze. If you did use the older stuff then when you look in the radiator you will probably see small chunks in it and if you take some out it will be soft and gelatin like.
 
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fredster

New member
If the antifreeze has never been changed, it's time to do it anyways, so flush all of it out and replace with good old green - no worries later.
 
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toddspolaris

Member
good call fredster, antifreeze change every 50,000 miles. transmission fluid every 40,000 miles and mineral based oil in motor every 4,000.
 
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eao

Active member
Don't put Dextron in the cooling system. First of all Dextron is a misspelling of Dexron and
Dexron is Automatic Transmission Fluid. GM brand name.

Dexcool is engine coolant used in all GM vehicles since 1996.
 
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scott_l

Member
cardinal43 said:
My GF has a 99 Grand AM with 110,000 miles. Last summer it needed anitfreeze, so I dumped in 50/50 green antifreeze. I didn't realize Dextron that it called for was any different from green antifreeze. I was recently at a Jiffy Lube and they told me that I am seriously damaging the radiator / pumps / cooling system by keeping the green antifreeze in there. (I am always skeptical of their advice)

The coolant is running low, so should I just add Dextron on top of the old green antifreeze from the summer?

Should I pay Jiffy Lube the $120 they want to flush the cooling system?

This car is old, but I'd like my GF to get as many miles as possible out of it.....
Click to expand...



just as important of a question.......where is the antifreeze going? It sounds like you have had to add it twice. That is not normal!
 
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mn_mxz

Member
I was wondering the same thing. Intake manifold gaskets are an issue on the 3.1 and 3.4 motors. I did mine at 168K, antifreeze was weeping out from the valley.
 
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phazerfx

New member
Been working a quick lube for 6 plus yrs.. Dexcool is junk its the red coolant do not mix it with regular old green antifreeze as one is a ethenal based and the other is a polyglycal or how ever u spell it they will sludge and gel up and cause you more problems.. Vehicle manufacthures recommend changing the dexcool every 150k but it needs to be changed asap. get a coolant flush done and try to get the old fashion green antifreeze put it.. google the dexcool recalls tthat GM has put out.. And chances are your intake gaskets are leaking thats why u are loosing coolant or your heater core is leaking also. 120 is kinda alot for a coolant flush my store charges 8995 and its a 16qt flush with a antifreeze thats called a global, mix with all coolant. we remove the upper rad hose and back flush threw the system. WATCH out for the scammer oil changes that use a tube type vacumn coolant flush they dont work worth crap. if u need more info let me know i got tons n tons of oil change experience for ya
 
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eao

Active member
Millions and millions of vehicles on the road successfully using DexCool for the past 15+yrs. It is an excellent product. Like anything, it can be misused, misrepresented and blamed for things that are not it's fault. Most of the problems associated with Dexcool are the result from the lack of maintenance or mixing of incompatible coolants. Just because they say its capable of going 100,000 miles is no reason to ignore your cooling system for 100,000 miles. I would get my company owned suburbans serviced at quicklubes and I had to watch them like a hawk. On more then one occasion I stopped them from adding the green coolant to the recovery tank on my GM vehicle. To many of the workers in the QL's, coolant was coolant and they would mix them without hesitation.

The world is a better place because of DexCool. In addition to all North American-built GM vehicles, Texaco extended-life coolant (DEX-COOL™) technology is either in use or approved for use by several other European and North American manufacturers.

Leaking intake gaskets are not the fault of Dexcool, they are the fault of the mismatch of aluminum intakes with iron heads and the poor design of the gaskets.
 
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yamahauler

Active member
eao: You are incorrect that dexcool isn't the cause of leaking gaskets. I had to replace my gasket and you could clearly see where the gasket was literally eaten away..yea, from dexcool. The problem is GM didn't use the right materials in the gaskets and as a result dexcool would break them down. There was a HUGE class action against them, they lost, I got some money back. The 2nd went bad in less than 9 mths...mechanic went to replace it and NAPA said they had to remove it from the shelf due to the issues I explained above. Mechanic ended up forking over some more dough and went with a nice stainless steel one with a good epdm or vitol o-ring/seal. No problems for 3 years now.

As for dexcool...my mechanic also said there is a misconception about the dexcool. It is also in the system as a lubricant for a pump or two. He also said you will never get out all of it when flushed so when you go to green...problems occur, maybe slower to arise but still occur.

As was stated above, if you are adding coolant, you have other issues that you need to get figured out as it is not normal for coolant to just disappear.

So, 1st figure coolant leaking issue, 2nd-flush and put the original stuff back in.

To see if you have an intake manifold gasket leak...look up and down the side of the engine with a bright flashlight....look to see if you can spot any coolant slowly running down side or where it may look like something is running by a stain. If you can't see any, check the oil..if it is milky or discolored it may be internal leak and you could have serious issues. Also, don't forget the obvious...drain plug o-ring (had that go bad twice)...leaky hose. Put down a piece of cardboard on the floor and park the car over it....do you see antifreeze on it after you back, if so, do it again and don't back out. Crawl under car and try to look directly up from where the drip is, may point to where leak is coming from

Good luck, hope it helps.
 
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ohning1971

New member
Anyone that has or is turning a wrench for a living while the US automakers started using "DEXPUKE" can tell you its crap from front to back. While most people that stand up for it rarely even service there own vehicle. Ask your local tech that you trust what he runs in his car or truck--will it be DEXCOOL? I think not.
The gaskets problems that everyone (GM especially) has had are not so much from the dissimiar metals (alum/iron). **** remember that muscle car you had in the late 60's or 70's on up to today that had a alum intake on iron heads. How many intake gaskets did you change? Its a combo of a bad design and the coolant. Yes it will degredate the plastic and corrodes like no other. I speak from my own experience not from what I have read or someone told me
 
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eao

Active member
I have owned several GM vehicles dating back to 1996 with Dexcool and never had any problems with mine. We had several GM vehicles at work and in the 5 +yrs and well over 100,000 miles of use never experienced one problem.

I wonder how they made Dexcool so smart as to only pick on certain vehicles?

Don’t make the mistake of thinking that mechanics know better. The best ones are essentially trained to be good at wrenching – efficiently and correctly. They’ve never had training in the sciences of fluid mechanics, heat transfer, boundary lubrication, tribology, metallurgy, fatigue stress fractures, or Root Cause determination with Failure Modes and Effects Analysis (FMEA) or other tools used throughout the world of automotive design and manufacturing.
 
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yamahauler

Active member
Yes---my mechanic does think dexcool is crap, but what he is saying is that switching it out isn't a good idea.

Eao: You must be luckier than most. Obviously some vehicles may not experience problems but a ton did. I believe the comment was made that it was cheaper to go through and lose a class action lawsuit of 43 million than it would be to issue a recall.
I was just stating proven facts, not busting your chops...that's all.
 
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ohning1971

New member
In my experience removing the t-stat and flushing with water will give best results. You will get 99 % and will not have any problems with mixing.
eao---can't figure why you said "I wonder how they made Dexcool so smart as to only pick on certain vehicles?" I read back through and no one said that. However your statment of Don’t make the mistake of thinking that mechanics know better absolutely kills me. You make it sound as if we are all parts changers. I'll give you that some are but then again I've worked with a ton of engineers that were book smart and talked a good game only to find out when they actually put their hands on something they were lost. That dipoma hanging on your wall behind your desk or an ASE patch on your shirt doesn't necessarily mean anything. You make it sound that we could not figure out the root cause of a failure unless we were told by an engineer. I've had a little of the training you listed,was I suddenly a better tech because of it? We know what works from trial and error, from being there and DOING that, from putting our hands on--not from theory. Its always a good place to start but ever run into a situation where how things added up on paper didn't quite work out in the real world?
 
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ohning1971

New member
BTW do you think GM used any of the fluid mechanics, heat transfer, boundary lubrication, tribology, metallurgy, fatigue stress fractures, or Root Cause determination with Failure Modes and Effects Analysis (FMEA) when they designed the gaskets using DEXCOOL as the coolant. I bet they did. How'd that work for them ?
 
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