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Discussion Starter · #1 ·
After lots of googling and searching on this forum, I can't seem to find what I'm looking for. I couldn't find it in the owners manual either.
Just wondering what the tipping point is on the LML in regards to ECT's? I'm not worried about where the operating temp should be as I know I'm good there. I'm already aware of the inaccuracy of the factory gauge. Just trying to figure out where I should set my alarm on my CTS. At what temp does damage start to occur on these engines?
 

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I have mine set at 230°, I know people run them alot warmer. I figure the the alarm should sound before it's a big problem and can easily pull over and check for problems before it gets too warm.

I don't tow in the mountains or in extreme heat so I generally don't see much over 220°.
 

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Sub for results

And is 185 ish operating temp.. That's what my cts reads when I'm all warmed up
 

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Discussion Starter · #4 ·
Yes 185* is pretty normal. That was the most I hit today with my winter front on. And it was almost T-shirt weather today. I generally hover around 181* on the CTS.

From what I understand 250* is when fluids start to break down. So that is about the point where any engine will start to incur damage. I knew gassers were always around there. Just wasn't sure if the Duramax was any different. 830King makes a really good argument for setting the alarm at 230*. I'd imagine you'd have to be pretty hard pressed to get these LML's up to even that temp.
 
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Hey all I just got a 2012 LTZ with 61k miles. It's all stock (for about a week!) but my average temp was around 210 on the ride home. Is that normal or should I get the dealership to check it out before I delete it? My cummins used to run on average around 185 so I'm somewhat concerned. This is my first DMAX so I'm not sure what's the norm for yall.
 

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Hey all I just got a 2012 LTZ with 61k miles. It's all stock (for about a week!) but my average temp was around 210 on the ride home. Is that normal or should I get the dealership to check it out before I delete it? My cummins used to run on average around 185 so I'm somewhat concerned. This is my first DMAX so I'm not sure what's the norm for yall.

Your good man


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So that's normal??
 

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Hey all I just got a 2012 LTZ with 61k miles. It's all stock (for about a week!) but my average temp was around 210 on the ride home. Is that normal or should I get the dealership to check it out before I delete it? My cummins used to run on average around 185 so I'm somewhat concerned. This is my first DMAX so I'm not sure what's the norm for yall.
Ya your good for some reason my analog reads identical to your but my digital read out (cts) will read 185-190

So In lamer terms your perfectly normal every duramax I've been in does this
 

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Thanks man you got me feeling a lot better haha
 

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181 then goes up to 185 then the thermostat opens drops to 177. stays about 183 on the highway.
 

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Well now that makes me worry Hahahaha ! I can't find a happy medium!
 

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Discussion Starter · #13 ·
The factory ECT gauge is completely useless. They are never very accurate. They have always been like that on the Duramax's. Unless you are overheating or warming up, they sit at the 210 mark for the most part. There are lots of posts on this. GM likely does it on purpose so that people don't see a fluctuating gauge and freak out. So when yours is saying 210, you're likely actually somewhere between 180* and 220*. But you need not worry about where your needle is sitting. If it starts going well over that line than you might want to pay attention, otherwise keep on truckin.
 

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I've noticed my factory engine temp runs 25 or so degrees hotter than my dashboard app shows the temp to be.
 

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The factory ECT gauge is completely useless. They are never very accurate. They have always been like that on the Duramax's. Unless you are overheating or warming up, they sit at the 210 mark for the most part. There are lots of posts on this. GM likely does it on purpose so that people don't see a fluctuating gauge and freak out. So when yours is saying 210, you're likely actually somewhere between 180* and 220*. But you need not worry about where your needle is sitting. If it starts going well over that line than you might want to pay attention, otherwise keep on truckin.
Part of the reason the gauges don't move much is because the thermostat is doing its job....

Closed til it reaches the 'start to open temp'. (so the engine warms up)

As it opens, more coolant is flows thru the radiator, increasing the effective cooling capacity. Then it varies how much it is open to maintain the coolant temperature at the 'operating' level.

Once the thermostat is wide open and flow is at maximum, increased heat load will result in higher coolant temps.
 
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2016 GMC is sitting on 210 once warm. That's kind of high isn't it or is the gauge just not accurate. Truck only has 500 miles on it. Gauge is not analog it's the LED type display found in the Denali truck.

That is regular driving temp on highway and city mixed I have not towed with it yet.
 

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GM makes them a "dummy" gauge, that way when you think its way to hot, its still in a ok range, I think it was smart for them to do
 

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210 showing is completely normal. The gauges point straight up when running normal. Over 230 be concerned.
 

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Normal operating temps are 185-210 so long as your inbetween those your fine
 
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