: Coolant temperatures



Smiling Jack
12-17-11, 10:06 PM
Questions specifically re, 2006 STS V6, but probably answers will have more general applicability:

1. How to interpret the temperature gauge ? I'm guessing top indication of the gauge marks is 220 F and bottom is 100 F

2. What is the normal operating temperature, and what position on the gauge is that ?

Thanks for any good info.

EChas3
12-17-11, 10:33 PM
I'd guess the bottom mark is 120, the center mark 200 & top mark 280.

A cooling system under pressure isn't dangerously hot at 240.

Both our V8's always run a tick below halfway (horizontal).

dkozloski
12-17-11, 10:58 PM
Mine reads the same; normally just a little below 1/2 way.

Smiling Jack
12-17-11, 11:11 PM
Thanks.

I was spoiled by the driver info display on my '95 Seville STS and its ability to show the temp digitally.

The N* usually ran at 206 F., as I recall.

EChas3
12-17-11, 11:20 PM
Our '98 STS ran exactly halfway at all times until it developed the HG malady.

Smiling Jack
12-18-11, 12:39 PM
Thanks.

I was spoiled by the driver info display on my '95 Seville STS and its ability to show the temp digitally.

The N* usually ran at 206 F., as I recall.

more:

That 206 F observation for my N* was probably in 100 F outside air temp with the A/C on.

Check of thermostat part applications at Stant site showed 195 F for the 300 HP N* and 180 F for the 3.6L V6.

Do those seem right to everyone ?

BaTu
12-18-11, 01:56 PM
Wait a min,,, you need to understand what today's "gauges" are all about ;)

You don't have the traditional gauges you're thinking of, what you have are idiot lights with a needle. The sending unit doesn't connect with the gauge but rather with the computer that "interprets" that information and sends to the gauge what it thinks is good for You! In an effort to limit unneeded service concerns, and give owners much confidence in their cars, your gauge has a Totally non-linear movement that basically says - Nothing (cold or off) - Normal (a Wide range that "parks the needle in a good place) - Nasty (you're in trouble things have gone wrong without really giving you an early Head-Up as it happens).

So, by the time your Temp gauge is close to, or in, the red you already have a Big Problem.

Here's a prime example -> http://www.intellidog.com/dieselmann/b_smoke13.htm

Smiling Jack
12-18-11, 03:07 PM
And here I was thinking that the temperature gauge would indicate the temperature.

Silly me !

So how do i read the temperature? Buy a Scan Gauge and read it from the OBB connector ?

KRSTS
12-18-11, 04:00 PM
Wait a min,,, you need to understand what today's "gauges" are all about ;)

You don't have the traditional gauges you're thinking of, what you have are idiot lights with a needle. The sending unit doesn't connect with the gauge but rather with the computer that "interprets" that information and sends to the gauge what it thinks is good for You! In an effort to limit unneeded service concerns, and give owners much confidence in their cars, your gauge has a Totally non-linear movement that basically says - Nothing (cold or off) - Normal (a Wide range that "parks the needle in a good place) - Nasty (you're in trouble things have gone wrong without really giving you an early Head-Up as it happens).

So, by the time your Temp gauge is close to, or in, the red you already have a Big Problem.

Here's a prime example -> http://www.intellidog.com/dieselmann/b_smoke13.htm

So why waste real estate on the dash, why not just use a light that glows red when cold, green at op temp, and red again if overheating?

BaTu
12-18-11, 04:54 PM
So why waste real estate on the dash, why not just use a light that glows red when cold, green at op temp, and red again if overheating?

I think you call it - Marketing... ;)

It must be HiPer/Sporty if it has gauges!


And here I was thinking that the temperature gauge would indicate the temperature.

Silly me !

So how do i read the temperature? Buy a Scan Gauge and read it from the OBD connector ?

I guess....

Smiling Jack
12-18-11, 05:14 PM
So, can anyone confirm that the actual temperature measurement data is available at the ODB connector?

BaTu
12-18-11, 05:51 PM
I know I get an actual degree-by-degree reading from my scanner (AutoEnginuity) from the OBD/CAN (OnBoardDiagnosis/ControlllerAreaNetwork ;) ) connector.

In fact, there are a whole bunch of digital gauges you can buy that do just that....

ddalder
12-18-11, 09:34 PM
Wait a min,,, you need to understand what today's "gauges" are all about ;)

You don't have the traditional gauges you're thinking of, what you have are idiot lights with a needle. The sending unit doesn't connect with the gauge but rather with the computer that "interprets" that information and sends to the gauge what it thinks is good for You! In an effort to limit unneeded service concerns, and give owners much confidence in their cars, your gauge has a Totally non-linear movement that basically says - Nothing (cold or off) - Normal (a Wide range that "parks the needle in a good place) - Nasty (you're in trouble things have gone wrong without really giving you an early Head-Up as it happens).

So, by the time your Temp gauge is close to, or in, the red you already have a Big Problem.

Here's a prime example -> http://www.intellidog.com/dieselmann/b_smoke13.htm
So first of all, I don't disagree with your comment that the temperature gauge is not actually connected to the sensor, but is instead interpreted by the PCM and data commands are send to the IPC commanding varying needle positions. Having said this, I believe some of what you state is an over-generalization and I don't believe it to be entirely accurate. Have you reviewed the Description and Operation section of the GM manual referencing the engine cooling system? There is virtually nothing I've found to support your claim that the IPC "parks the needle in a good place". The link you have provided refers to Ford vehicles, and more specifically, transmission fluid temperatures. This isn't to say some technology or strategies can't cross over. I simply don't accept your wide spread "generalization". Based on my experience in dealing with a large fleet of vehicles, what you are suggesting is not what I've found to be true in real life.

Smiling Jack
12-18-11, 11:58 PM
So, perhaps someone who has a device to read the OBD data could answer the original questions as to what temperatures correspond to the gauge marks and also as to what the normal operating temperatures are (at this point presuming that the answers - or at least the latter answer - might be different for the V6 and the Northstar)

ddalder
12-19-11, 12:39 AM
So, perhaps someone who has a device to read the OBD data could answer the original questions as to what temperatures correspond to the gauge marks and also as to what the normal operating temperatures are (at this point presuming that the answers - or at least the latter answer - might be different for the V6 and the Northstar)
So the short answer to your question is no. There are published tables that correlate the coolant temperature to the approximate resistance of the sensor. There is not any information (at least in the model year of GM manuals I have access tonight) that will correlate temperature to gauge position.

I can tell you that in almost all circumstances, when my car is at operating temperature, the needle is slightly below the half way marking. When scanned, it reads 90 - 91 degrees. Occasionally, on a hot day, I've seen it reach as much as 100 degrees and there has been some increased needle deflection.

The best I can offer is (over the next few days when I have time) to map markings between cold and normal operating temperature indicating the scanned temp with my Tech2 at each of the first several gauge markings.

Smiling Jack
12-19-11, 01:00 AM
So the short answer to your question is no. There are published tables that correlate the coolant temperature to the approximate resistance of the sensor. There is not any information (at least in the model year of GM manuals I have access tonight) that will correlate temperature to gauge position.



I can tell you that in almost all circumstances, when my car is at operating temperature, the needle is slightly below the half way marking. When scanned, it reads 90 - 91 degrees. Occasionally, on a hot day, I've seen it reach as much as 100 degrees and there has been some increased needle deflection.

The best I can offer is (over the next few days when I have time) to map markings between cold and normal operating temperature indicating the scanned temp with my Tech2 at each of the first several gauge markings.

Thanks, Darcy.

"90 - 91" should be 190 F to 191 F ? or were you talking C ?

Note my comments above. N* apparently uses a 195 F thermostat and the V6 uses 180 F

ddalder
12-19-11, 01:03 AM
Sorry... Yes, I am referring to degrees celsius. That would be 194F (90C) or 195.8F (91).

AllWheelEric
12-19-11, 11:38 PM
I knew there was a reason I bought an OBDII scanner (ELM327). I watched it today while it was about 30F outdoors. Here's what I saw:

Bottom (1st) tick mark = cold
2nd tick = 48C or 114F
3rd tick = 64C or 147F
4th tick = 81C or 178F
5th tick = midpoint of the gauge, and my car doesn't get that warm. It sits around 85C, with the gauge between the 4th and 5th tick marks.

ddalder
12-19-11, 11:46 PM
Interesting. So what I gather from this is each division looks to be about 16 degrees C. Which engine do you have?

Smiling Jack
12-20-11, 12:57 AM
Thanks to Eric for doing this work and posting the results.

Thanks also to Darcy for the question:



Interesting. So what I gather from this is each division looks to be about 16 degrees C. Which engine do you have?

I'd like to know which engine Eric is observing, but it would seem that 180 F for the V6 and 195 F for the N* would both lie between the 4th and 5th marks.

Spyke
12-20-11, 10:05 AM
I know that on the v6, the termostat starts to open at 194F and is fully open at 225F (Gm spec).

During the winter, my cts and my dad's sts both v6 runs between 194-200F

During the summer, both runs between 200-220.

Smiling Jack
12-20-11, 10:33 AM
I know that on the v6, the termostat starts to open at 194F and is fully open at 225F (Gm spec).

During the winter, my cts and my dad's sts both v6 runs between 194-200F

During the summer, both runs between 200-220.

I infer, then, that this is model year dependent.

As I have posted previously I believe that for 2006, the V6 thermostat is 180 F and the N* is 195.

I also have noted previously that in 100 F outside temperature, and heavy A/C use, my '95 N* sat at about 205 F.

AllWheelEric
12-20-11, 11:05 AM
Interesting. So what I gather from this is each division looks to be about 16 degrees C. Which engine do you have?
That's on the 2005 V8 1SG which includes a "performance cooling package." It does appear that the gauge is linear.

MacMuse
12-20-11, 02:35 PM
OK, fun with iPhone & Rev2 app.

84114

ECT in the upper right corner 190 while the needle showed...

84115

Yes, I have a CEL. Just came on last night. No noticeable problem, appt. set for Thursday morning.

Greg00coupe
12-20-11, 09:46 PM
thanks Batu. yes your explanation that its not really a gauge makes sense to me. mine hangs below 1/2 in ALL types of weather. I wondered why it never changed? Question is when there is a problem what will it to? Just jump to H or move up gradually? I suppose there will be some DIC message. I know in cars with real gauges once you learn the patterns in the temp gauge monitoring it is a good indication of a developing problem.

C&C
12-21-11, 05:52 AM
thanks Batu. yes your explanation that its not really a gauge makes sense to me. mine hangs below 1/2 in ALL types of weather. I wondered why it never changed? Question is when there is a problem what will it to? Just jump to H or move up gradually? I suppose there will be some DIC message. I know in cars with real gauges once you learn the patterns in the temp gauge monitoring it is a good indication of a developing problem.

Your gauge sounds as it is performing properly; the thermostat (when function properly, as yours is) regulates the engine temperature and keeps it at the just below half level. Your cooling system has excess capacity to cool (when needed if functioning correctly) and the thermostat will restrict the flow to maintain the proper temperature, which is required for economy and engine efficiency. If you encounter a increase in load, and the cooling system just can't keep up, you may see a slow rise on the needle; if your thermostat fails (in the closed position) you'll probably see a much sharper rise in needle position. If either condition reaches an attention getting point, the DIC should indicate a high temp problem.

Smiling Jack
12-21-11, 10:53 AM
..............................,,,,,,,,,,,,,
..........
........... if your thermostat fails (in the closed position) you'll probably see a much sharper rise in needle position. If either condition reaches an attention getting point, the DIC should indicate a high temp problem.

My info is that (at least for the V6) the thermostat has a by-pass mode; so that when it is stuck closed the coolant can flow around it. With this by-pass, the symptom of a stuck-closed thermostat will be an operating temperature that is a bit too low, i.e. the opposite of what we would traditionally have expected.

Can someone please confirm or correct this?

C&C
12-21-11, 11:45 AM
I can't be sure either way; the Service Manual doesn't mention anything about a thermostat bypass. (except when not up to temperature sending coolant bypassing the radiator). I know they sell thermostats that, if becoming inoperable, will stick in the open position, (which would just delay warm-ups as you described); don't know though.

Smiling Jack
12-21-11, 01:10 PM
I can't be sure either way; the Service Manual doesn't mention anything about a thermostat bypass. (except when not up to temperature sending coolant bypassing the radiator). I know they sell thermostats that, if becoming inoperable, will stick in the open position, (which would just delay warm-ups as you described); don't know though.

Thanks.

Anyone got any additional info ?

KRSTS
12-21-11, 06:47 PM
I believe all modern thermostats are designed that if they fail, they will remain in the open position.

Smiling Jack
12-21-11, 08:17 PM
Thanks for the education.

I guess it's myself that is "stuck" (in the past).

I tend to think of "modern" in regard to cars as referring to anything that developed after I started driving (1960).

Thinking back, I used to laugh at my Dad when (in the 60's) he re referred to cars made after World War II as "modern."