mellojoe

I live in Arizona. Temps in the 110+ consistently. Daily driving to and from work, about 40 miles roundtrip. However, the car is running at 230*F fairly consistently, coolant temp.

• Already emptied and refilled with fresh 50/50 dexcool
• Already cleaned debris out of radiator and condensor heat exchangers
• Nothing is leaking
• Coolant tank is full and remains full (overflow tank is right at the line)

What do I check next? Water pump? I don't see any leaking at the waterpump area, and nothing dripping under the car. The belt doesn't seem to be slipping and there is no belt squeak/squeal that I can hear. Thermostat? I thought these were all designed to fail open. A/C runs ice cold. Heater (never used other than to test) blows hot with no smell of coolant.

What do I check next?


((edit))
2007 C6 3LT Z51 LS2

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SixAddict

Yokesc5

Bruze

Did something recently change? In other words -- did it use to run cooler, but is now running noticeably hotter?

What is the oil temp?

mellojoe

Oh, that's good to know. At least I'm not completely alone in this.



Did not flush. Just a drain and refill.

Drive is mostly highway, 75mph. Pockets of traffic that are 5 lanes of 30mph.




I've only owned the car about 4 months now. So this is my first summertime experience with her. Still, though, 230*F seems really high, especially as others on this site report fairly steady 190 to 210 max (I've searched threads for awhile, anything related to cooling systems).

I can't find where I wrote down the Oil and Trans temps. And its currently haboob / dust-storm season here in Phoenix, so I'm carpooling with the wife in her SUV (i drive, she drinks coffee XD ) but that means I can't check on Oil and Trans temps right now. I could have swore I wrote them down ... I'm getting old.

C6in816

I have a 2007 as well it shocked me when i saw mine hit 228 but it did that in traffic now once on highway it goes down and if you blow heat for a short bit the temp should go down but 228 230 it will do these cars air damn for the radiator leaves no room for airflow. but I change my thermostat to a 160 I purchased the ligenfelter one. If it gets to hot it will go into limp mode not sure what the # is but if you see it hit 150 turn car off it will warp the head.. Make sure you didn't get an air bubble in the line as well .... 230 is bad but you should be ok also check the filter for airflow and clean those radiator fins

ptroxx

EVRose

I wouldn't say 230 is normal. I'm in 110° traffic a lot here in Vegas and I've never seen anything over 220° and as soon as it hits that the fan speeds up and it starts cooling off.

mellojoe

stock only (at this time). 95,000 miles.

Cherokee Nation

You should of spent a few bucks on a 180 stat..And with that many miles a radiator flush is mandatory.

enventr

jaredtxrx

1: 230* isn't that bad in 110* heat.
2: Don't change the thermostat, it's a waste of money.
3: You may want to do a full flush and fill and make 100% sure to get rid of all the air in your system. (My guess is that is your current issue)
4: How cold does it get there in the winter? You may even consider upping your water ratio. Maybe 60-40 or 70-30.

Landru

Does fan activate, a'tall?
If not that may be contributing to high op temps.
Been reported in AZ & TX due to excessive heat fan connector gets brittle, eventually breaking.
No fan cooling even if ECM's calling for it.
Carefully inspect wiring & connector to fan.

Make certain fan's working, if it isn't not an expensive or difficult repair, DIY even less.

Vette_Fan

While doing a Radiator Flush, I've heard you should do it backflow to really clean it, not just the drain and fill.

Anyone knows the method for backflow?

Dano523

Back flowing it more of a matter of the heater core since it has smaller passages, and more so on motors that have iron blocks since it will be pushing more rust through the lines.

So on heater cores, you remove the two lines to the heater core, and flush water through the core both ways, to flush out any rust partials that may be trapped in it.

As for the LS motors since they are all aluminum (including the heater core), the distilled water flush alone is resolve most of your problems. Trust is, when I do the distilled water flushes since replacing the T stat is part of the mix, will leave the T stat out of the distilled water flush, and the install it right before I go to add the new mixed dexcool at the end.

Now if I go to do a flush and the intial dexcool coming out of the system is a ***** show to begin with, then take some extra steps.

Step one is to pull the radiator hose off the bottom of the radiator, remove the T stat, as well the heater core lines, so I can break out the garden hose to start flushing the system that way to begin with, including reverse flowing through the heater core as well. Once I get clean that way, put the hose back on, break out the distilled water, and flush that way with the motor heat. Once the distilled water flush is coming out clean (may take a few distilled water flushed with running the motor cyles), then is time to install the T stat, make sure the system is buttoned up, fill with the Dexcool mix, then use vaccum on the tank to burp any air still in the system.

As for the opt problem, would day to say that there is either crap still in the system that was not flushed out, made the mistake not replacing the T stat at flush, still has air in the system,maybe even has a problem with the raditor fan not coming on, or just a ton of crap in the A/C heat exchange or radiator external passages that needs to be hosed out instead.

On the later, most of the time you can just spray water from the nose of the car/back of the raditor to flush debris out such, but somethings you can get a lot of debris between the A/C heat exchanger and the raditor, and you need to pull the heat exhanger forward to be able to garden hose out the debris that way instead.

Yokesc5

mellojoe

Yes, fan runs. I've verified that it runs and everytime I turn off the car, I can still hear it running for several minutes. Fan seems to be in good physical shape, too. No broken blades, etc.

Andysherman

As others have suggested, flush it with distilled water, maybe go 30/70 water/coolant... may bring it down 5-10 degrees. FYI, mine in normal driving in summer here in PA & at DE beaches it's 210-215, with headers, when outside temp is >90 then gets to 220, 225 in stop-&-go traffic. You still should be ok, though...your coolant temp sender can also be the culprit & not recording temps perfectly.

rsb213

This may not be the problem what so ever, but do yourself a favor and check the electrical connector on the fan. It melts on the majority of C6's. I bought my C6 in Chandler last year and mine was melted causing my car to run hot because the fan wouldn't always run.