Does anyone know at what coolant temperature the "idiot needle" moves up and out of the normal range (50% on the gauge)?

I've been conducting a little testing to prove to myself and to MINI that my driving lights are not contributing to my overheats. Put the lights back on to day and took a drive up to Mt Charleston. It was around 110 degrees to day and the computer read as high as 94 semi steady and peaked briefly at 95. Last week I drove it around town without the lights and it rarely reached 94. But...it wasn't nearly as hot outside and I didn't push it up a hill in high gear (low RPM and therefore low water pump speed).

The point of my question is whether a degree or two matters or does it have to climb another 10-15 to even move the needle. really want to have a convincing argument to MINI that the lights aren't a factor

Anybody know?

 

Anyone?

 

I'm not totally sure, but I would think that the gauge runs on the sensor, which is basically a rheostat that defines what the temp is based on resistance. If you use a paperclip or wire to totally cross the wires (no resistance, it would jump into the red, if you could vary the resistance, or measure the resistance on the temp sensor you could determine how hot it has to go to move the needle.


Also- a Scangauge will show you the coolant temp, and also the computer trick with the reset button in the speedometer will show coolant temp from the computer (option 7 I think?)

 

Thanks for responding...

I used the computer test mode to read the coolant temp directly so that isn't an issue. The eyeball average temp was about 2-3 degrees higher than it was before I reinstalled the lights. That could have been the fact it was really hot that day, or the fact I was driving uphill.

I did notice that the idiot temp needle never moved off dead center.

Either way, my issue is whether 2-3 degrees is "in the noise" or if that is pushing me dangerously close to an overheat.

I understand that I can drive the needle by changing the voltage, but unless I know what temp equates to what voltage that doesn't really help.

 

I don't think that 2-3 degrees is sufficient to move the needle any noticeable distance. And I'm sure its not the difference between normal temp ~185-195 degrees, and overheating, which is around 220 or more (usually...)

I would start to wonder weather the overheating is due to a faulty fan...or something of that nature...

what are the symptoms of overheating?

 

You must be new here . Go here for the whole gory mess, but in short after 8 coolant blowouts the dealer finally found that my head was warped. machined and reinstalled. Then they said they wouldn't reinstall my driving lights because their location is blocking the lower radiator and "probably" contributing to the problem. As I said above, the lights (at most) add a couple of degress to the water temp...I say at most becasue the hill and ambient temperature were probably a factor as well.

That said, stating that 220 is a typical overheat temp is helpful.

Would still like to know however at what temp does the needle leave dead center...

 

Sin MINI
I have the ScanGauge II and have seen temp from 160 to 202 and the temp gauge never moves off center. Not sure what it takes to move the gauge into hot but I would expect more than 220.
The stock gauge is mostly worthless.

 

Tell me about it...it basically confirms what you already know after you see coolant streaming out behind you...

Plus, a warning light should be in front of your face, not off to the side in the Speedo.

<sigh>

 

I have a Defi Control Unit and Digital display on my '05 MCS. The water temp will run at about 190 on the highway. It climbs quickly to 224 when the car is sitting at idle, at which point the thermostat opens. Temp quickly drops back to about 205. It's cool to see how this process works and reassuring to see that thermostat open like clockwork at 224 degrees. I guess my point is, the only way you can really monitor your water temp is to install a gauge of some kind. You should be able to pick up a decent Autometer water temp gauge for about $70 and it's pretty simple to hook it into your upper rad hose. It's worth it just for the peace of mind. IMHO.

 

Thanks, but I have no issue about how it's DESIGNED to work. I used the OBC in test mode and saw the same things (never got over 202 however)

I'm looking for the temperature at which the engine is determined to be overheating and the needle begins to move. I have had several overheats and from expereince the needle gives you no warning....partly because it goes up so fast from "normal" to "hot" but also because it's out of sight over on the Speedo.

So, at idle you've seen it get as high as 224? That's much higher than I've seen...Does the temp needle move at all?

 

I have the OEM NAV unit so there is no needle, or anything for that matter, until the overheat idiot light pops on (hopefully). That's why I went with an aftermarket system. You can watch the digital readout climb real fast when the car sits at idle, but it comes down just as fast when the thermostat opens up. Did you check that your thermost was actually opening?

 

After the 3rd overheat they replaced it. After the next one they replaced the thermostat housing. After the next three the TS appeared to be working. Turned out I had a warped head. The machined and replaced. Everything is running OK for now, but it did each of the previous 8 times as well, just before the coolant would blow out.

 

Granted I'm not an expert in this, but I've never seen a car where if it's going to overheat, the temp gauge slowly goes up. All of them had a normal temp gauge one minute, then maxed out the next. This makes sense considering a thermostat failure or pressure loss would cause the engine to rapidly heat up.

The temp gauge on my Chrono pack also appears to be more then just an idiot gauge. If I switch from freeway to stop/go driving I can see the needle climb about a needlewidth or two before the fans kick on. Considering it's just a 180 degree sweep covering 220F, you would only get one degree of movement for every 1.2F degrees the temp change. That's not much. Fortunately I just use it to tell when the engine is warmed up and ready to be thrashed on!

Sin,
I do however feel your pain regarding the light placement. I had a cracked thermostat housing once and my engine overheated when stuck in traffic. I didn't notice for awhile because the light was so fair out of my field of view. I have to think about checking the temp to see or notice both the gauge and light. It was then that I realized that my gauge was definitely working like a real analog gauge as it was several needlewidths past normal on my drive back (was able to get back home with enough airflow to keep it from overheating again, but still hotter then normal).