: Seville/Deville temperature gauge-2000-2004



Submariner409
11-04-08, 11:16 AM
The attached gauge with photoshopped temperatures was created by one of our members a couple of years ago by blanking off the radiator with cardboard and logging the temp rise. I installed a ScanGauge and here's what I get under normal driving warmup.

Compare these figures with the gauge tick marks, beginning with tick #1 at 9 o'clock. Remember that the thermostat on these Northstars starts to open at 188 and is fully open at 206.

#1 - <90 degrees
#2 - 115
#3 - 140
#4 - 165
#5 - 190-208 (desired operating range, needle steady)
#6 - 225+

Caddyshack100
11-04-08, 08:04 PM
That is really neat, its one area of the car that I always thought needs improvement, the gages really dont tell you anything, I know some people decry the digital dash in the Devilles but at least they will tell you what you want to know in the area of engine management.

ted tcb
11-09-08, 09:02 PM
For the 96-97 STS, there is a hack procedure that will bring up the operating temp on your DIC display. I did it, and loved having that info at my fingertips. Sadly, it doesn't work on the post '98 cars.

Some speculate that GM felt the typical older owner demographic would panic if they saw their cars temp steadily rise to operationg temps of over 208 on hot days, so the DIC info was omitted ... shame.

JimD
11-10-08, 11:36 PM
....Sadly, it doesn't work on the post '98 cars.
That is why I used my OBD interface box plus laptop to read the reported coolant temperature in degrees and relate that information to temperature guage position; I was not concerned about "overheating; I was simply curious about the actual numbers.


Some speculate that GM felt the typical older owner demographic would panic if they saw their cars temp steadily rise to operationg temps of over 208 on hot days, so the DIC info was omitted ... shame.
The temperature guage driver is digital and the sample rate is too slow (in my opion). The slow sample rate allows/causes the needle to 'jump' slightly as the coolant temperature cycles through 'normal' variations.

Some demographics might get nervous about seeing the temperature guage 'jump'. I bet the fuel needle gets more attention than the temperature needle.

Submariner409
11-11-08, 11:17 AM
You'll see a LOT of posts in here about the gauge needle moving past about 12:00.

Most so-called "gauges" are so heavily damped that they are useless. A modern car driver would panic if they could actually observe the oil pressure cycling from 15 psi to 60 psi, up and down, in the course of normal everyday driving. Same for a temperature or vacuum gauge.......nothing in an internal combustion engine is static, and especially with an electric fan cooling setup, temperatures hop all over the place. I daresay JimD has seen his coolant go from 194 to 224 and back a skrillion times, which is normal. If some of our posters actually saw what was going on, there would be a rash of coolant threads and perceived "problems". Better to damp out the information than create bogus service problems. Granny would have a fit: "My gauges move !! Something's wrong......"

Jim, The gauge driver looks to me like it usually counts in 2 or 3 degree steps, sometimes not. In any event, the ScanGauge makes my driving experience more comforting.

JimD
11-11-08, 07:15 PM
....Jim, The gauge driver looks to me like it usually counts in 2 or 3 degree steps, sometimes not. In any event, the ScanGauge makes my driving experience more comforting.
I have logged several cold start (<60 degree coolant temperature) situations trying to get a sense of what toggles the PCM from open loop to closed loop.

Two degree jumps in indicated coolant temperature dominate the log files. One degree and 3 degree jumps do happen, but the 2 degree jump is by far more common before the thermostat gets in the game.

Submariner409
11-12-08, 03:09 PM
Right on.......Just did a 45 degree - 216 degree warmup and the ScanGauge climbed in 2 degree steps. I'll have to designate one of the gauges to show the loop sequence vs. temperature. The thing can show any 4 of 12 gauges simultaneously. www.scangauge.com

Right now I'm watching coolant temp, intake air temp, timing, and throttle position in %.

tman2093
11-27-08, 01:03 AM
I'm going to add a gauge with actual numbers eventually. I don't want it to look tacky at all, I'm thinking to put it under the kick panel in the drivers seat footwell where I can see it if I want, but it's not an eyesore

Submariner409
11-27-08, 09:54 AM
One of the difficulties of adding either a mechanical or electric temperature gauge to a Northstar installation is the lack of extra cooling jacket plugs which are large enough to pull and then thread a thermocouple or sending unit into. The existing sending unit is, in fact a thermistor (temperature-dependent resistor), so the ScanGauge discussed elsewhere makes a viable addition to engine status monitoring because the car's system already monitors engine temperature to within 2 degrees F.

Submariner409
03-04-11, 07:40 PM
Here's an update..........