Temp gauge is asleep!

[bigbluebus2500]

Just got my first Caprice, it's a '94 woody wagon.
The temp gauge is not working but it does move.

Here's what it does.
Key in position 1 (off): needle is at about 25%
Key in position 2 (engine off, ign. on): needle is all the way to the left (Cold)
Key in position 3 (starter engaged): needle abruptly goes all the way to the right (Hot)
Once engine starts, needle abruptly goes back all the way to the left again, and does not move from there, unless the engine is turned off again, then it moves about 25% towards hot.

Question: Since the needle does move, is the problem related to the sender switch or the gauge itself?

[luckydriver]

i have this issue with my SS...get it fixed asap..i tried 3 different senders on the engine and none worked so i let it go..then one day the engine stopped because i overheated and it's not a pretty thing. once the new engine is in i'm going to try the OE sender and hope thats the issue but if not, ill be running lines for a dash temp sensor for sure. ill never drive with a broken gauge again

[bigbluebus2500]

Originally Posted by luckydriver

i have this issue with my SS...get it fixed asap..i tried 3 different senders on the engine and none worked so i let it go..then one day the engine stopped because i overheated and it's not a pretty thing. once the new engine is in i'm going to try the OE sender and hope thats the issue but if not, ill be running lines for a dash temp sensor for sure. ill never drive with a broken gauge again

I would like to and I'm trying to get it fixed as quickly as I can, but no one here has responded yet with the location of the sender or possible cause of the gauge's erratic behavior.

[luckydriver]

pass side of car near back of engine is an aluminum type cylinder which is a heat shield..i think it's between the rear plug and 2nd one) .pull the heat shield back and the sensor is under there..need a deep socket (maybe plug socket, i forget) and just unscrews but antifreeze pours out so be quick! i've changed this 3x so i'm an expert at it now!

i forget what brand of sensor my parts guy gave me but hope the OE part works. my gauge was tested by my mechanic (jumpering it) and he said the gauge itself works since it was pegged during the test..so i'm assuming has to be the sensor..

this is NOT our cars but it is what the sensor looks like

http://shbox.com/1/temp_sensor2.jpg


part 50 here

http://parts.nalleygmc.com/showAssem...modelYear=1995

[Jim Spahr]

There are two Coolant Temp Sensors on the LT1 engine. One is on the pass. side cyl. head where the diagram shows no. 050. The other one is on the water pump at the very front of the engine. One feeds the engine temp. to the PCM and the other feeds the engine temp to the dash coolant temp. gauge. I am sorry I can't remember which does which. Shoebox on the F body version of the LT1 should also show a CTS on the water pump. A long while back, some B body owners were using a three wire coolant temp sensor and rewiring it so that this one sensor would send the same temp. to both the dash gauge and the PCM. The temp, you saw on the gauge was what the PCM saw. Both of the stock CTS were a two wire sensor.

[luckydriver]

dash gauge is the pass side

PCM is the water pump

[bigbluebus2500]

The sensor on pass side has only 1 lead. I thought that a coolant sensor for a temp gauge would need 2 leads.

Ok so what is the sensor in the very back of the engine on top, under the EGR valve? It has 3 leads.

[1slow96]

Pass. side temperature "SENDER" only needs one wire. My problems with this were damages to the wire/connector. I believe the item you refer to at the back of the intake is for oil pressure.

[chevyryder26]

im going through this right now, i replaced one but i guess ill have to try to waterpump one next....anyone have exact part numbers from advance or autozone? or does this need to come direct from chevy?

[chevyryder26]

dude at advance gave me three part numbers wt3025 ,wt3025z, w3t000z, and 36403... if you search advance autoparts website they will show up, so far ive tried wt3025 and no change....