Question if related to overheating (Page 1/1)
Fieros4evr AUG 25, 09:05 PM
I read the recent topic about overheating and followed the steps to pinpoint issue. I have a 1987 Fiero 4 cyl. and this was the result:

-No fan running on acc & start
-Fan runs ONLY when climate control is turned to ON in the car. (No cold air working)

I saw in the other topic about the Compressor related to fan function but I don’t think that I have a compressor installed in my Fiero. Attached are photos of what I see. These photos are the best that I could take due to tight location. These views are standing from the back looking in the direction of the passenger side firewall.





This photo below are the connectors for the compressor, which has been sitting like this in the engine not connected since I brought this car.



So, My question is: Could the unplugged compressor wires in my car have any relation to the overheating issue?

Thanks for viewing.

[This message has been edited by Fieros4evr (edited 08-25-2023).]

Vintage-Nut AUG 25, 09:18 PM
TO ME - No.

Did you read these threads?

Hot Wired Radator Fan by MasterBaker
https://www.fiero.nl/forum/Forum2/HTML/147129.html

180 or 195 Thermostat by MasterBaker
https://www.fiero.nl/forum/Forum2/HTML/147099.html

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Original Owner of a '88 GT and 'Under Refurbishment'

[This message has been edited by Vintage-Nut (edited 08-25-2023).]

Patrick AUG 25, 09:31 PM

quote
Originally posted by Fieros4evr:

...the overheating issue



What are the indications of "overheating"? Is coolant puking out of the coolant reservoir?
Fieros4evr AUG 25, 09:58 PM
Vintage , Yes. Read them All test done according in both. Result, all I mentioned.

Patrick, no puking (knock on wood) just temp gauge goes to red markings/ far right without ac switch turned on.

[This message has been edited by Fieros4evr (edited 08-25-2023).]

theogre AUG 25, 10:05 PM
87 L4 has different rad fan wiring.
Has Nothing to do w/ AC wiring except AC/Heat control head can make it run.

Dash gauge reading at 220-230°F does Not = overheating.
ECM sees ~220°F on it's own sensor then ECM turn on the Rad Fan.

See cave https://web.archive.org/web...cast.net/~fierocave/
Rad Fan and rest of cooling section.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Vintage-Nut AUG 25, 11:08 PM
The only Iron Duke I had was my ’84 2M4 SE....


quote
Ogre's Fiero Cave
87-88 Fiero with the 4-cylinder DIS motor, the ECM controls the fan. These cars have no fan switch in the block. The ECM activates the single speed fan at 225°F and turns it off below 211°F. The fan is also activated by the AC as in previous models. (The ECM is able to run a 2 speed fan or a second fan but I am not aware of any 87-88 4 cyl that is setup for either.)



My '88 L4 ECM circuit shows the Coolant Temp Sensor feeds the ECM (pins 8 & 12) and the radiator fan relay is pin 21.

Try to ground wire 21 and see if the fan will turn "On". If yes, check the Coolant Temp Sensor and don't believe the failure is the ECM relay....

Of course, the coolant system is "Full" meaning no air; the thermostat and radiator cap are 'good' and the water pump is working.

Edit: Added a Link which has more info on the Coolant Temp Sensor..

Question re '87 cooling fan by waynrayn
https://www.fiero.nl/forum/Forum2/HTML/141586.html

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Original Owner of a '88 GT and 'Under Refurbishment'

[This message has been edited by Vintage-Nut (edited 08-26-2023).]

Fieros4evr AUG 26, 03:07 AM
VintageNut & theogre, Thank you for replying. I will spend the weekend following the information you provided. I will give you both an update soon.