DexCool coolant level

[New]

Hi,

I have read that DexCool is especially sensitive to air. To be more precise, once the coolant level drops and air gets into the cooling system, rust and sludge develops pretty quick.

I have a GM 3800 Series II engine and the coolant level is ok when cold but a little low when hot.

How come? What should I do ?

 

[obbop]

If the vehicle is still under warranty keep the DexCool and ensure the radiator cap is in good condition (all of it, the rubber gasket, everything). Ensure there are no leaks in the system. Keep the holding tank full. All the typical stuff.

If the vehicle is out of warranty I would seriously consider a very thorough flush and using the latest new-fangled non-DexCool coolant.

Beliefs vary about the DexCool stuff. Some folks swear it's super neato. Others curse it, revile it, condemn it to the depths of heck with all the 1st generation Chevy Vega engines.

Try a search of the board with "DexCool" as a search term. There have been many posts about the subject.

Until my warranty is over I will stick with the stuff and keep the cooling system well-maintained. When the warranty has been relegated to the ash heap of history alongside Richard Nixon, Barbary Coast pirates, and honest politicians I will have to consider switching myself.

 

[Ray H]

quote:

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Originally posted by New:
I have a GM 3800 Series II engine and the coolant level is ok when cold but a little low when hot.

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Probably nothing to worry about. If your GM vehicle only allows you to observe the coolant level through the transluscent expansion tank, and over time, the coolant level may decrease. Antifreeze doesn't normally boil off or evaporate, but the water content will gradually decrease from evaporation. That, in turn, would result in a gradual reduction in volume of the coolant that might be first noticable at the "Hot" marking on the expansion tank. (It would affect the "Cold" level, too, but might well still be above the minimum marking - leading you to mistakenly believe something was wrong.) Nevertheless, the radiator may well remain full at all times. I'd bring the hot level up to the full "Hot" marking at operating temperature (using at least 50% concentraion of DEX-COOL) and then keep close tabs on whether the level drops back when the engine is at normal operating temperature for awhile. If it does, you might have a problem with gasket leakage internally - dealer time. Also keep in mind that with the onset and progression of fall, even when warmed, your car's not going to tend toward taxing the cooling system to the degree it did during the summer months - even though the engine fully warms, the rise in the expansion tank may be less than during the hot summer months.

 

[Matt_S]

In my experience, the cold and hot lines are only an approximation. I've never had a car where the coolant would rise exactly to the hot line after being filled exactly to the cold line. Don't worry about it. The important thing is that you're consitent when you check the level. IMO, the best way is when the engine is stone cold after sitting overnight. You'll get the most precise reading that way. I also usually pull off the radiator cap to make sure the radiator's also full.

 

[Ray H]

I've never come across one on my wife's 2000 Cavalier. No radiator cap, no radiator draincock, no dipstick nor fill tube on the transmission - the "GM Mark of Excellence" in action...

 

[Ray H]

quote:

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Originally posted by ChrisW:
Don't many newer cars have remote pressurized overflow tanks?

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RANT MODE: On

Exactly so - but that's my point since that "feature" leaves no way to directly observe the condition of the radiator's metal innards. I'm not particularly keen on stressing the bottom tank plastic hose connection any more than absolutely necessary either. Seems that American car makers have all but conspired with their dealer networks to insure replacement radiator sales/service to the unwary by elliminating removable radiator caps and drain-cocks.

RANT MODE: Off

 

[ChrisW]

quote:

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Originally posted by Ray H:
I've never come across one on my wife's 2000 Cavalier. No radiator cap, no radiator draincock, no dipstick nor fill tube on the transmission - the "GM Mark of Excellence" in action...

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Don't many newer cars have remote pressurized overflow tanks? And as for the radiator draincock, I've read on this board its easier to use the lower hose, except sometimes it can be hard to manuver off.

 

[segfault]

One of the articles I've read about the DexCool fiasco recommended filling the tank to the "Max hot" mark when cold, to protect against evaporation.