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Topic: Primary Fan Runs all the time

in Forum: C4 Cooling and Heating Systems

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Primary Fan Runs all the time (1/7)
5/27/18 10:19am

aldocar
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Joined: 12/3/2016
Posts: 92

I had new blistein shocks put on my 88 and what a difference I love them. Since car was in the shop and I purchased a new temperature switch that was to kick on primary fan at 200 deg and shut off at 183 deg I had my friend install the new temperature switch. He also flushed the system and changed top and bottom hoses. Car runs a lot cooler but the fan comes on at 175 and the car will never run lower than 175 in a million years so fan stays on. Solved temp problem but this will not be good for fan motor. His wiring is to the primary relay under master cylinder. The temp sensor has to be screwed up. Car runs between 183 to 195 that's just 1 day. the old range would be 188 to237 in traffic.

Time to install a manual switch? Some how I knew this would end this way I should just ignore the dam digital gauge.

Thanks for any help. Oh i got a good price on the shocks from Mid Atlantic 400 free shipping.

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Re: Primary Fan Runs all the time (2/7)
5/27/18 10:17pm

Hot Rod Roy
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Mission Viejo, CA - USA

Vette(s):
Yellow '84 Coupe

Joined: 3/18/2015
Posts: 74

What is the part number of your new coolant temperature switch? I am using an ACDelco D1855B, and it works fine. It's rated to turn the fan on at about 215* and off at 200*.

Cool

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Re: Primary Fan Runs all the time (3/7)
5/28/18 6:32am

aldocar
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Posts: 92

Eckler's part # 25113224-1 on at 200 deg and off at 185deg. I checked it out this morning and I see that he put a sealer on the sending unit the instructions said not too it was self grounding. Could the sealer read hotter than the bare unit and will the sealer burn off through use. I let it idle and the temp never went over 184 this is good when in traffic. I had this done about 2 days ago and have not used car except for sort trips.

thanks for your help and Have a good memorial day!!

Since the wiring is done I could order a new sender and put it in. I would check with Eckler before doing this.

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Re: Primary Fan Runs all the time (4/7)
5/28/18 11:06am

Hot Rod Roy
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Mission Viejo, CA - USA

Vette(s):
Yellow '84 Coupe

Joined: 3/18/2015
Posts: 74

aldocar said:

Eckler's part # 25113224-1 on at 200 deg and off at 185deg. I checked it out this morning and I see that he put a sealer on the sending unit. The instructions said not to, it was self grounding. Could the sealer read hotter than the bare unit?

With a sensor with 200* on, and 185* off, the thermostat probably isn't opening all the way, so the fan will run all the time. The thermostat is trying to raise the temperature of the engine, while the sensor/fan is trying to lower the temperature! Yes, I'd call Eckler's. There is nothing that could cause the sensor to be at a higher temperature than the coolant. There would need to be another heat source for that to happen. Since the fan and sensor are working, the sealant on the sensor isn't causing any problem.

Cool

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Re: Primary Fan Runs all the time (5/7)
5/28/18 3:38pm

aldocar
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Joined: 12/3/2016
Posts: 92

Thank you!!!!

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Re: Primary Fan Runs all the time (6/7)
6/2/18 5:55am

aldocar
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Joined: 12/3/2016
Posts: 92

I called Eckler's and it came down that they had problems with the sensor coming on at the correct temp. He was honest enough to tell me at this point I will wire in a manual switch and when I hit 210 I will turn on the fan this temp only occurs if stopped on hot day or slow traffic. I could have pushed for a new temp sensor but if this one fails I will go to the ac delco that you have and eliminate the manual switch. Thanks for helping me out!!! This is the last purchase from them there are better shops out there.

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Re: Primary Fan Runs all the time (7/7)
6/13/18 6:10am

aldocar
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Joined: 12/3/2016
Posts: 92

Just completed wiring up the manual switch it was easy as the new temp switch wiring was easy to follow. I was able to run wire by battery through the door hinge area and into car someone had mentioned this area. Car is running at 185 to 188 on back roads when having fun with the curves it hits 190 to 194, have not been on pike but all seems fine I did add a water wetter product that seems to reduce by about 2 to 3 degrees. Along with new shocks I replaced top and bottom hoses and new antifreeze. I left the back up fan to come on based on original set up my thinking was if both were tied to the manual switch and I had a problem with the switch at least I had the back up fan at 230 plus.(plus I did not know how to do this with out blowing something up) Have a great summer and watch out for the many idiots that are on the road and multiplying as we speak.

|UPDATED|6/13/2018 7:10:59 AM (AZT)|/UPDATED|

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