Antifreeze change

Just finished changing the antifreeze and rad. hoses on my '99' 3.5 and thought I'd share some of my findings.
Your better off removing the air dam to get at the drain and the lower hose - only 5 or 6 10mm bolts.
Couldn't figure out the drain valve - it wasn't like the one pictured in the manual gave up and just removed the lower hose.
I removed the engine drain plug which you have to take the right tire and splash shield off to get at. I used a 5mm allen wrench and it was pretty tight. Once I got it out the AF shot out and drained about a gallon of AF that the block holds.
After hearing the horror stories about Dex-cool I was afraid of what my AF would look like after 134,000 miles. It looked like new, no gunk or sludge, just a nice orange color. I ran a bottle of cooling sys. cleaner and clean water thru just to be safe.
The top rad. hose was not a prob. - just had to trim a few inches off the new one.
The lower one was a different story. The one the parts store gave me was nowhere near the orig - about twice as long. They tried telling me that it was "cut to fit". No thank you. I tried every parts store I could find with no luck. Tried GM - $30 plus shipping and at least a week to come in, no thanks again. I ended up putting the orig. one back on.
I did find some on the web but couldn't be sure they were the right ones either.
I removed the purge vent from the top of the rad. and filled it with a 70/30 mix till the AF came out of the vent, put everything back together, and hopefully will be ok for another 100,000.

new radiator hoses last a long time 10+ years (watch for chafing). I Armor-All mine so they last longer.

For your mix usually you go 60/40 or 40/60 max. Does it matter that you went 70/30? = 70/30 is fine and is actually the max.

http://www.peakantifreeze.com/faq.html#B
A. Why is it important to mix antifreeze with water?
Antifreeze contains chemicals that protect your engine against rust and corrosion, as well as freeze-up and boil over protection. Water is required to activate the chemicals in the inhibitor package. Furthermore, adding water to antifreeze actually increases the freeze-up and boil over protection provided. For example, a mix of 40% antifreeze and 60% water provides freeze-up protection down to -10°F and boil over protection up to 259°F. In comparison, a mix of 70% antifreeze and 30% water provides freeze-up protection down to -62°F and boil over protection up to 270°F. However, we do not recommend adding more than 70% antifreeze. This would limit the corrosion and freeze up protection and heat transfer capabilities of the antifreeze.

http://www.theherd.com/articles/dex_cool.html
early thoughts on Dex-Cool

Dex-Cool is extremely impressive compared to anything else currently available. Personally I am converting ALL of my vehicles over to Dex-Cool. For the Impala, I even installed the '96 Dex-Cool labeled reservoir cap and Dex-Cool "Notice" sticker for the radiator cover, exactly as they come on the '96 Impala. The Dex-Cool reservoir cap is available under #10285918 and cost me $3.29.

-I wonder if this guy removed his Dex-Cool Notice sticker?

Dexcool Mixture (coolant/water) Freeze Point Boil Point
50/50 -34 deg F 265 deg F
60/40 -62 deg F 270 deg F
70/30 -84 deg F 276 deg F

70/30 is the max.

Just did a complete flush and fill on my 98 w the 3.8L and dual climate control, heat was blowing cold. Back flushed the system as well as the heater core. Heat now works at times and doesn't other times. Read in the Chilton'r manual could possibly be "Heater Control Valve" Any one know location of valve? Is it a hard repair to do? Any one have this problem??

Thanks
Tom

Did you bleed all the air out of the system?

Yes I bleed the system out more then once, Actually primed the heater hoses as well as using the bleed on the Thermostat housing.

It's important to change the coolant about every 5 years because if the additives in it prevent the migration of aluminium ions from one part of the block to another, i.e., aluminium erosion in one part and aluminium scale in another. I had the dealer change/power flush my coolant at about 5.5 years. Before I had it done I noticed a silver tint in the coolant in the overflow reservior. I try to change the coolant in the reservior once a year to add some more additives.