A friend with an '01 Z28 had his mechanic tell him to take the Dex Cool out and put regular anti-freeze in. Says the Dex Cool will eat up his water pump and radiator. I was always under the impression that we had Dex Cool because of our aluminum systems. Who is right?

 

Time for a new mechanic...
You got it right. Dex-Cool is used because of the aluminum engine. It's also used in other GM iron-block/aluminum head engines. Some of the european cars use "extended life" coolant as well. Don't switch away from Dex-Cool to the green stuff. It will lead to internal engine corrosion.

Abe

 

Yea the mechanic's an idiot. Run from him.

 

Dex Cool is fine in all aluminum engines like the LS1. On engines that have cast iron blocks or heads, if the engine is run with low coolant levels, things can start looking nasty in a hurry.

 

Only a dork would make a comment like that. GM moves forward in technology and I am sure that millions have been spent on engineering....and wether Dex-Cool eats cooling systems. Putting green ethylene glycol in is going back in time. Dex-Cool protects better and last longer.

Never mix the two either.

 

This is one of those subjects that there is so much incorrect information floating around that it is almost humourous. First of all, both Dex Cool and the standard green antifreeze are both ethylene glycol based. If you don't want to take my word for it, just read the labels. Contrary to popular belief, it doesn't hurt a thing to mix the two, except once the green antifreeze has been introduced into a cooling system with Dex Cool, you loose the extended life benefit of the Dex Cool. The main difference between the two is that the green antifreeze contains silicates and the Dex Cool has a different corrosion inhibitor package that does not contain silicates, but is slightly more acidic. It is also important to not use more than a 60/40 Dex Cool / Distilled Water ratio in a system designed for Dex Cool.

 

You all have pretty much expressed what I was thinking. Why would GM put Dex Cool in our cars and then warrenty them if Dex Cool was back for the cooling system? However, my preventative maintenance background tells me not to wait 5 years. Thanks

 

I also wonder why Gm was smart enough to put the distributer right under the weep hold on the water pump on the lt1's.


Thats 1 more brillant move from GM.


On the topic of dex cool. I switched to the green stuff last year, and car runs great. Never over heats, and this year i didnt have to unclog the heater core for a first

 

I always love it when people decide they know more than the engineers that designed the system.

"nah, you dont need dex cool"
"On what basis"
"none"

When OEM's reccomend something, its for damn good reason 99% of the time. The more specific, the more id follow it. If they say 5-30, use 5-30. Its what the whole engine is based on.

if they say change the ATF every 60k miles, dont do it at 90. They have done extensive testing and that is what the fluid can handle.

If they say to use Dex cool, its probobly not because orange was their favorite color.

 

Stock is not always best, and that is why we run longtubes and do throttle body bypasses. GM is involved in a lawsuit right now because the dexcool they recommend clogs up water passages. There is better anti-freeze for LS1's than dexcool. The factory doesn't always do things the right way the 1st time, that's why there are so many recalls. Oil analysis has shown that the mobil1 5-30 that GM recommends allows twice the wear as mobil1 5w40. The German castrol has also proven to be a better oil for LS1's. It doesn't always pay to have blind trust in the manufacturers recommendations.

 

Maybe I should rephrase that. Unless you actually know what you are doing (some sort of testing), you are a fool if you think you can just decide what is best. I thought the whole "on what basis" "none" covered that though.

Clearly, improvements can be made to the engines. Performance is an obvious area.

Id be interested to see these oil results.

 

The second part of what I quoted is definitely correct. I used to be a Service Manager at a tire store/service center. I have seen what happens to a cooling system when someone follows GM's original recommendation about how long Dexcool will last. DO NOT let your cooling system go for 5 years without flushing it. It's not pretty. Then again, GM has revised that figure so even they can admit making that mistake.

The first sentence of what I quoted...exactly which coolant is better for the LS1? And in what dilution? And most importantly, why?

Abe

 

QUOTE:Id be interested to see these oil results.

Do a search over on ls1tech. There are alot of people who do oil analysis and have shown these results. You can check out some of Patmans posts over there. He is the oil expert. The 5w30 is thin to start with for a 30 weight rated oil and with time thins even further. The mobil1 5w40 on the other hand is thin for a 40 weight oil and works great, showing less engine wear. As far as the dexcool goes, there are better options. If you do choose to use dexcool, just make sure you change it frequently.

 

ive had slight buildup with dexcool but overall its hasnt been bad but ive had it changed a few times as was stated already.


i thought i remember reading GM stopped using dexcool in trucks because of problems with it.



id highly recommend not waiting 5/150 before you flush it out.

 

Facts on dexcool... It does not contain silicates, however if it is ever mixed with the green antifreeze that we all have come to know and use it will create lava rock type substance. This is a known fact and I am living proof of it. My wife has a 98 saturn (GM product), which she said was having cooling issues, well she decided to put in the green antifreeze. After about 3 months the overflow tank looks like a lava rock science project, you can only imagine what the rest of her cooling system looks like.

A wise man once said, if it works dont fix it. This would be my simple input for dexcool. If your car came from the factory with it, I would suggest sticking with it, however make sure you flush your cooling system every now and again, and NEVER EVER switch to the green stuff unless you plan on never going back to dexcool.

With that being said, do as you will.