hello fellow vetters....ive just started noticing that me engine fan has started coming on right after I start the engine before the motor has even started to reach the normal cut on temp....it doesn't do it all the time,but was wondering if this is an indication to something that is going to be a major problem...any thoughts or suggestions will be appreciated..tnx jerry.

 

Just recently had the same problem on my 1990. The primary fan would come on and the analogue gauge would still show a cold state. I checked with my AutoXray scanner and when the fan came on the reading would jump from 157* to 235* and when the fan shut down the temp would drop and this was after a 2-3 minute cold start up. I did lose power also during this problem. Per Hooked on Vettes forum member the first thing to do was change the Coolant Temp Sensor at front of engine on intake as this feeds the ECM with data while the sensor between #6 and #8 plug on passenger side feeds the data to the analogue gauge. Still had the same problem so following his directions I traced the yellow wire from the CTS to the green connector of the ECM. The pin # was 16. Did a voltage check. Cold should be below 5 volts and as the engine heats up the voltage drops but when the temp spiked on my scanner the voltage did not change so the new CTS I installed was okay. That left the ECM as faulty so got a remanufactured one and all was okay. Note that I only had 22,314 miles on the car so was disappointed the ECM went but we are talking 23 year old part and located under the hood with all that heat. You will need to scan the ECM to see what temp it reads to verify a problem. Thought early on it might also be a fan relay but it wasn't as I had a spare new one.
Hope this helps and OP chime in with other thoughts.
Bill

 

The Fan also, comes on anytime the AC or Front Window Defroster is on.