# Coolant Temp Questions



## Falco21 (May 11, 2010)

After discovering the "secret menu" in our cars, yes I know I am slow lol I have been driving around with the coolant temp showing. I just got back from running some errands and had a few questions. 

After starting the car and warming her up, the coolant temp stayed between 175-180 while driving around. I then hit slowly moving traffic that I was in for a maximum of 15 minutes. I noticed that the temp went up to around 215. Not sure if this is alright, but then for the rest of the time driving it stayed above 200 degrees but never over 225. I have not yet washed out the radiator fluid and refilled since I purchased the vehicle about 15k miles ago. Should I do this? Or are these temps nomral? If not what could be the cause?


----------



## Poncho Dan (Jun 30, 2009)

Almost sounds like you have a 165 thermostat. 175-180 is cold, stock is supposed to open at 189 or something like that.


----------



## Falco21 (May 11, 2010)

Yea I am pretty sure the owner before me had a 165 thermostat installed. But the running temp being at 225 is normal? Either way I am going to flush the system today. Yesterday my dad tried to help out and added normal radiator fluid into the tank of dexcool/distilled water so I gotta flush the entire system. I just asked him. I was just curious if those running temps were normal.


----------



## Poncho Dan (Jun 30, 2009)

On a stock tune, yeah. GM lets the coolant get to a ridiculous temperature before the fans turn on. Mine was that way before I tuned it, now its set for fan 1 to engage at 195, fan 2 at 197, and both will run until 192 if both have been activated. It never touches 200 anymore.

Some might say that's a little excessive, but you can't go wrong with keeping your ECT in a tight 10° range. Consistency is a good thing, IMO.


----------



## Falco21 (May 11, 2010)

Yea see its reasons like this that just provide more reassurance in purchasing HP Tuners. Quick question though. The local auto parts store sells Dexcool 50/50 Mix and Dexcool Pure. I found a writeup on how to flush the system over at ls1gto.com and it seems pretty straightforward. The only question I have is after flushing everything out, how much dexcool do I put and how much distilled water? Each container of Dexcool is 1 gallon and the manual states the car needs 12 quarts. Do I just purchase one gallon of Dexcool 50/50 and then put that in first then fill the rest with distilled water?


----------



## HP11 (Apr 11, 2009)

50/50 is water and Dexcool. If you did that you'd dilute it farther than necessary. I always buy the pure Dexcool and mix it in a larger container with a gallon of water.


----------



## svede1212 (Nov 1, 2005)

I think it's cheaper and easier in the long to just by the premixed stuff. Distilled water is over a buck a gallon, you have to make another stop on the way home and then you have to mess with mixing it. Premix, unscrew cap, pour it in.


----------



## HP11 (Apr 11, 2009)

I use filtered tap water.


----------



## Falco21 (May 11, 2010)

So then if I were to buy the Dexcool 50/50, how many gallons would I need? I read on the other forum that 2 gallons is enough, but the manual says 12 quarts.


----------



## Falco21 (May 11, 2010)

Well just finished. I flushed the system with the hose. Opened up the drain plug and started the car with the heater blowing. After everything was drained out I turned the car off and let it drip till it was completely dry. Replaced the plug and filled her up with 1 gallon of Dexcool Pure and 1 gallon of Pure Distilled Water. These 2 gallons filled the radiator plug perfectly. Started the car and she ran perfect. Temperature reached the highest 185 degrees. Now I am going to let it sit for a few hours then go back out and check fluid level and fill to desired level.


----------



## Poncho Dan (Jun 30, 2009)

Adding water is a matter of opinion really. Techs will tell you that you need distilled water. Service information per the Helms factory manual will tell you "clean, drinkable water" indicating that tap water is fine (which, it usually is unless you have rediculously hard water). Keeping up with the 5 year change/flush interval is usually the most critical.

When I did it I used Peak 50/50 for ease of use. It's still green, but it said all over the place that it was 5 year/150K mile stuff. Plus I flushed the crap out of her. What I didn't know was that the rinse-off still kills your grass. :lol: I collected everything I could that drained out, but even the diluted stuff I hosed off the driveway turned the grass brown within a day. My lawn doesn't look like the pristine golf course that it did a week ago...


----------



## Falco21 (May 11, 2010)

Well the car is a 2005, so its probably 6 years now for the first flush. That's if the owner before me didn't already do it. When I drained it, the fluid looked good though. Bright orange and nothing in it. I just wanted to flush it for the maintenance but also because of my fathers mistake lol 

Is 2 gallons of fluid enough though? It seemed to fill it up perfectly and even when idling, it drained a little out of the drain plug due to a little over fill


----------



## Falco21 (May 11, 2010)

Went back out and opened up the radiator cap and the fluid had dropped a few inches. Filled her up full and headed over to my gf's house. On the way there I stopped to get gas and when I came out from inside, there was a puddle underneath the drain plug. The engine temp when driving never went above 180 and when sitting still never above 220. Is the fluid on the floor just the system releasing the excess? My temperature gauge reads perfect and my temperature seems fine.


----------

