Instruments - Temperature Gauge Reads High
Group Ref.: Electrical TroubleshootingBulletin No.: 338118
Date: November, 1993
SUBJECT:
TEMPERATURE GAGE READS HIGH, ENGINE DOES NOT OVERHEAT (INSTALL REVISED HARNESS AND COOLANT TEMPERATURE SENSOR)
MODELS:
1992-93 CHEVROLET CORSICA/BERETTA
(WITH 3.1 L V6, VIN T, RPO - LHO)
Condition:
Some vehicles may exhibit a high temperature gauge reading without an overheat condition.
Note:
If the engine temperature indicator lamp is on *and* the temperature gauge reading is high, this procedure will not apply. Please refer to the appropriate service manual section.
Cause:
Coolant temperature sender location combined with a 2 wire sensor may cause local gauge readings which are not representative of entire coolant temperature.
Correction:
Verify if the cooling system is functioning properly.
1. Check cooling system for proper fill and insure that there are no leaks.
2. Check coolant for proper glycol/water mix. It must be set at -34 degrees Fahrenheit, (-1 degree Celsius), (50-50 mixture). Too much glycol reduces the heat transfer and will make the gauge indicate hot. Coolant should be checked from the radiator drain cock (not the surge tank). An optical refractometer (J23688 or J38633) should be used. They are temperature compensated.
3. Check ECM coolant temperature with vehicle fully warmed up. Tech I should read 196 - 206 degrees Fahrenheit, (91 - 97 degrees Celsius), at normal driving conditions. At prolonged idle, ECM temperature will increase as total system heats up until coolant fans activate at 228 degrees Fahrenheit, (109 degrees Celsius).
4. Check sender and gauge function using appropriate Service Manual procedure. If no other causes for gauge high temperature readings are found, replace ECM temperature sensor with a new 3 wire temperature sensor (located in the intake manifold) and install revised harness. The revised harness will allow the temperature gage to obtain temperature readings from the coolant sending unit located in the intake manifold, allowing the temperature gauge to be representative of the entire coolant system.
1. Remove air cleaner assembly.
2. Locate the coolant temperature sensor connector from injector harness.
3. Cut off and splice the kit supplied harness to the harness end of the connector. Stagger the cuts so the splices do not overlap, approximately 40 mm (1-1/2") apart.
4. Splice like wires, purple to purple, yellow to yellow.
5. Remove insulation 10 mm (3/8").
6. Slip heat shrink wrap over wire before splicing wire.
7. Solder wire ends. Insure the connection is secure.
8. Slide heat shrink wrap over splice and heat with heat gun until sealed.
9. Cover with plastic conduit and tape conduit.
10. Secure the harness along the engine wire harness with wire ties supplied in the kit.
11. Disconnect coolant sender connector located on right side of engine (view A) and connect new coolant sensor harness into respective terminals. See Figures 1 and 2.
Parts Information
Harness Kit P/N 12154414
Sensor P/N 10096181
Parts are currently available from GMSPO.
Warranty Information:
For vehicles repaired under warranty, use:
Labor Operation Number: T3388
Labor Time: 0.6 hrs.