My Uncle recently gave me a 96 2.4L Cavalier with 73,000 miles on it. The reason he gave it to me is because he said that it either had a cracked block, warped head or blown head gasket. He thought this becasue there was a dark muddy color in the antifreeze in the reservoir and it was kind of thick. I had the car for a couple of months now and have driven it maybe 4,000 miles. I check the oil and antifreeze religiously. I might have added about 1/2 a quart of oil and about a gallon of fluid. He gave me a 3/4 full gallon of green antifreeze with the car. So I know he has been using the regular stuff.

I have been reading on this site about mixing Dexcool and the regular stuff and have heard mixed things about it. I finished the rest of his green antifreeze before I read anything about it. I have not noticed the black muddy look in the reservoir since. Is it posible that the discolored muddy looking fluid in the reservoir was just the dexcool and the regular antifreeze having some kind of reaction to each other?

The car drives very strong and I do not smell any antifreeze in the exhaust. I have not had to add any oil since about the first 500 miles after I got it. I have been hesitant to do a cooling system flush in case it is a gasket and the flush would make it worse.

Any thoughts or comments would be appreciated.

Thanks

Scott

1996 Purple Cavalier LS 2.4L. No Mods.

Oh my gosh!!!! U never mix dexcool with the normal green antifreeze EVER.I would HIGHLY reccommend doing a coolant flush thoroughly and decide if u want to run either the dexcool or normal green antifreeze.Combining the two are a no no.The goop is a result of mixing and it would be wise to clean that out,with some prestone flush.If the car is not over heating I would also replace the thermostat due to if it's the original it would be a good idea.As for the oil issue run a can of seafoam in the oil ,yes pour the whole can into the oil fill cap area and run it for a 100 miles to clear out anything inside the engine,while not necessary I would and change the oil after that and filter.I would def go with the coolant flush and refill with either the dex or normal green it really won't hurt the engine to change it depends on ur choice.I would go green it's cheaper and does a very good job regardless.If anything I said is inaccurrate or someone wants to add or correct me please do so and that is it.

There are green antifreeze manufacturers that make mulit purpose antifreeze, But I would drain and flush with plenty of water before switching to any of the green. They do say that you can mix them But I wont on a customers car,
Im going to have to say that its the dexcool that was causing the muck. Any one that has a gm vehicle with dexcool knows that It causes muck. I wouldnt rule out the head gasket though, especially because you say that you have been adding coolant. Usually the gasket fails in the front driverside corner of the head, with a noticeable muck growth where the block meets the head. I have never seen muck in the antifreeze in the cavs caused by the head gasket though. head gasket usually causes overheating and coolant loss. Cracked heads are common in the older third gen.

: flush coolant, replace with green multi use coolant (advanced auto parts)
: Watch coolant level after driving a while
: If you have to add alot get the head gasket done before you crack it from overheating with not enough coolant.


01 cav w/01 3400 gam gt 4t45e

When ya change the oil and it looks like a caramel color then ya know ya got a blown head gasket. And you will see a lot of steam coming out of your tail pipe.
And whats seafoam?

Seafoam is a multipurpose cleaner. I think it is usually for like buildup inside the engine. You can put it in the engine oil, or you can pull the vac tube that goes to the brake booster and stick that in the bottle to suck it in. After doing this and driving with it for awhile, it is imparative that you change your oil.

Mixing the green and dexcool is bad as previously mentioned. I think if you let it go too long you will have to replace the radiator because it will clog it up.


"The Blue Bullet"

Dexcool can be mixed with many other "green" brands, but you MUST check the label to be sure.

Blown Headgaskets are common on the Quad series engines.

Ron Love wrote:Oh my gosh!!!! U never mix dexcool with the normal green antifreeze EVER.I would HIGHLY reccommend doing a coolant flush thoroughly and decide if u want to run either the dexcool or normal green antifreeze.Combining the two are a no no.The goop is a result of mixing and it would be wise to clean that out,with some prestone flush.If the car is not over heating I would also replace the thermostat due to if it's the original it would be a good idea.As for the oil issue run a can of seafoam in the oil ,yes pour the whole can into the oil fill cap area and run it for a 100 miles to clear out anything inside the engine,while not necessary I would and change the oil after that and filter.I would def go with the coolant flush and refill with either the dex or normal green it really won't hurt the engine to change it depends on ur choice.I would go green it's cheaper and does a very good job regardless.If anything I said is inaccurrate or someone wants to add or correct me please do so and that is it.

i'm on 27k miles since i mixed dex-cool with regular green antifreeze. no problems.



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