C4 Low Temperature Cooling Fan Kit

[retiredSFer]

I own a 1993 40th Anniversary 6-speed that comes close to overheating in the summer as I live in the desert southwest (115-120 degrees). The secondary fan comes on at 238 degrees and I want to lower that number to 185 degrees using a 1984-95 (C4) 185 degree Low Temperature Cooling Fan Kit. Has anyone made this conversion? The instructions refer to the “Factory Cooling Fan Switch.” The service manual refers to an “Engine Coolant Temperature (ECT) Sensor.” Are they the same thing? The instructions say it is located on the cylinder head between spark plugs one and three or six and eight. The service manual shows the ECT on the lower water pump housing. Connecting the secondary fan relay is pretty straight forward, but I am not sure what sensor or switch to remove. Also, assuming I remove the right one, will bypassing the ECM cause codes to appear? I own a Z06 too, but it does not come close to overheating in the summer. Can anyone help? ROGER

[c4c5specialist]

HI there,
The 2 pin sensor on the water pump is specifically for the ECM and engine operation, do NOT modify that.
Your fans are temperature controlled by the ECM.
If they are NOT coming on at 228, there is a problem.
Also, check for debris in front of the evaporator/radiator assembly.
Allthebest, c4c5

[retiredSFer]

Originally Posted by c4c5specialist

HI there,
The 2 pin sensor on the water pump is specifically for the ECM and engine operation, do NOT modify that.
Your fans are temperature controlled by the ECM.
If they are NOT coming on at 228, there is a problem.
Also, check for debris in front of the evaporator/radiator assembly.
Allthebest, c4c5

Thank you for your response. Both fans come on at the correct temperatures per the service manual. The problem I have is in the summer months where outside temperature can reach 115* or higher. As long as I am on the highway the temp is fine, but in traffic it runs extremely hot. What about reprogramming my PROM to turn the fans on at: Primary on/off: 205/195 and Secondary on/off: 210/200 along with a 160* thermostat?
Thank you again for your assistance.
Roger
Las Vegas

[c4c5specialist]

HI there,
I believe that you have debris in your radiator/condenser assembly.
If your other car doesnt have this issue, the fans should cool down the vehicle easily.
Allthebest, c4c5

[retiredSFer]

Originally Posted by c4c5specialist

HI there,
I believe that you have debris in your radiator/condenser assembly.
If your other car doesnt have this issue, the fans should cool down the vehicle easily.
Allthebest, c4c5

Thanks, I'll check again. My other cars are newer and they seem do fine? Traffic in Las Vegas is becoming stop and go and with 115*-120* outside temperatures, it is like opening an oven door. Thanks again.

[irfgt]

If you have your A/C on, the fans should run constantly negating the need for a different fan switch or programming. You do not want the fans to run until they are needed. It kills engine power and puts undue stress on the charging system.

[retiredSFer]

Originally Posted by irfgt

If you have your A/C on, the fans should run constantly negating the need for a different fan switch or programming. You do not want the fans to run until they are needed. It kills engine power and puts undue stress on the charging system.

Thanks for your response. As long as my AC is on, the primary fan is on. The secondary fan does not turn on until the temp reaches 238*. I just want the secondary fan to come at a lower temp as the summer months are brutal in the desert SW. I can have my PROM reprogrammed vs. adding a switch or sensor which bypasses the ECM. Thanks again.
ROGER

[c4c5specialist]

Originally Posted by retiredSFer

Thanks for your response. As long as my AC is on, the primary fan is on. The secondary fan does not turn on until the temp reaches 238*.
ROGER

Once again, if your secondary comes on with the primary already on, there has to be something in the cooling module restricting air flow.
Allthebest, c4c5

[retiredSFer]

Originally Posted by c4c5specialist

Once again, if your secondary comes on with the primary already on, there has to be something in the cooling module restricting air flow.
Allthebest, c4c5

I do agree with you and tomorrow it goes up on jack stands and I will look for a restriction.

[ken mohr]

Originally Posted by c4c5specialist

Once again, if your secondary comes on with the primary already on, there has to be something in the cooling module restricting air flow.
Allthebest, c4c5

He is right. You should see what was in mine. Very seldom do I get to 210* now. Never if I am in motion.