Coolant sensor

[manlion]

1. Is the temperature sensor (in/by the water pump) controlling the temperature gage the same sensor that controls the EEC and HVAC "-24" reading?

2. I find info on a sensor located in/by the water pump(it is a thermasitor).

3. The one in the block is for the idiot light (it is just a switch).

According to this post about troble codes:
http://www.buickforums.com/forums/showthread.php?p=43614#post43614

Has this information been decoded?

According to Cory: (Page 1)
-24 is the WP.

According to one member (Thanatos), (Page 2)
"-08 is indeed at the WP. THe reading defaulted at 173* or something close, when unplugged".

According to (Electralt1) (page 2)
Used the HVAC method to read the codes on the LT1 i swapped into a 85 Electra estate. What i also observed is that -08 & -24 seem to be the same. One is fahrenheit and the other is celsius. Both readings seem to go up together when idling from cold start. Diagrams indicate that the tranny has a temp. feed to the PCM but one would expect the tranny to heat up at a delayed rate because no work is being done at that point and the thermostat has not opened.

As far as I know, there are two temp sensors on this LT1. The ECT sensor and the gauge temp sensor. Only one sends a signal to the ECM, the other sends its impedance to the dashboard gauge; there is no [COLOR=blue !important][FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif][COLOR=blue !important][FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif]cylinder [/FONT][COLOR=blue !important][FONT=verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif]head[/FONT][/COLOR][/FONT][/COLOR][/COLOR] sensor communicating with the PCM. Later this week i will observe more thoroughly the HVAC info and maybe borrow a scanning tool.

 

[MrBuick (Magnum)]

we don't know what -08 reading actually is. I has been said it is the sensor in the head, but I don't buy it.

 

[frostydevil]

We actually do not know what the -08 reading is. -24 has been confirmed as the temperature at the water pump in Celsius. This coolant temp sensor in the Water Pump is what sends the signal to the ECM and in turn is read through the HVAC or climate control. It is also what determines when the idiot light turns on as this is controlled through the ECM and throws a code.

The coolant temp sensor in the passenger side head, between cylinders 5 & 7, is for the dash guage reading only.

 

[manlion]

I think the one in the block does the idiot light. It is just a switch.

 

[paart]

I think the one in the block does the idiot light. It is just a switch.

I don't think so. It's been awhile since I "messed" with mine, but if you ground the wire at the head sensor, I think you'll see that the dash temp gauge goes to maximum. I think it's also unlikely that it is the "-08" reading since that one wire appears to go directly to the the gauge.

 

[manlion]

Do you remember if when you grounded the wire from the one in the block did the idiot light come on?

 

[MrBuick (Magnum)]

There is no coolant sensor in the block. There is one in the passengers side head, or the Water pump.

 

[manlion]

My mistake. I am just visualizing the picture I saw. I thought it was in the block. However, I am sure it was called and referenced as a switch. The one in the water pump is specified as a thermister. Therefore, I am wondering if the one in the head is for the idiot light.

Another question: if a scan tool is hooked up would it read the same temperature as the -24 on the HVAC?

 

[frostydevil]

Once again....
The sensor in the head, between cylinders 5 & 7, controls the dash guage only.
The idiot lights are controlled through the ECM and the sensor in the water pump sends the signal to the ecm, that just happens to be available to view through the climate control.

Another question: if a scan tool is hooked up would it read the same temperature as the -24 on the HVAC?

I would think so....

I am actually doing alot of research on this sensor, not just on this forum, and I have not really read anything conflicting as far as the info I have just told you. My dash guage is completely dead at the moment, and not to hijack your thread, does anyone know what else, besides the sensor would cause this? i.e. ignition switch module perhaps? I have heard that just changing the sensor in the head will "most likely" not fix it, and the issue is more likely to be somewhere else. Any truth to this?

Or....Has anyone installed an aftermarket guage? Which one? And how and where did you install? Is it fairly easy?

 

[bonscott]

Any news on the mysterious -08 reading?
Put a new 180° F stat in my car. I´ve notice that the -08 reading mostly fluctuate between 178° and 182° while the -24 reading at the waterpump is between 92°-95° Celsius, both readings do correlate with each other, if one goes up the other does it too.

 

[The Roadmaster]

Once again....
My dash guage is completely dead at the moment, and not to hijack your thread, does anyone know what else, besides the sensor would cause this? i.e. ignition switch module perhaps? I have heard that just changing the sensor in the head will "most likely" not fix it, and the issue is more likely to be somewhere else. Any truth to this?

Or....Has anyone installed an aftermarket guage? Which one? And how and where did you install? Is it fairly easy?

My dash gauge was dead. Changed the temp sending unit and it works fine now.

$7.85 part at NAPA

 

[bradlarsen]

my temp guage was not working on my 93 RMS, replaced the temperature sender, $29.00 which is on the side by the cylinders, and the guage now works. The temp sensor by the thermostat was also done, and all codes were eliminated after restarting. Replaced the co2 sensor on the manifold, and my gas mileage improved like new.