still overheating and being weird (Page 1/16)
cartercarbaficionado JUN 07, 08:46 PM
finally got some hot days and it's been 85 degrees and it finally started to overheat again and make some interesting noises so I'm not sure what's going on but I'm gonna try that better fan mod and the low temp fan switch to try and remedy this again. also getting a bumperpad air dam to graft to the aero style front end
armos JUN 07, 09:26 PM
Fan switches haven't been reliable for me.
If your car is AC equipped then you can force the fan on by turning on the AC, even if the AC doesn't actually work (mine doesn't).
If it can't easily stay cool with the fan on, then you have a mechanical problem with the cooling system.
1985 Fiero GT JUN 07, 09:34 PM
It should easily stay cool without the fan, the fan should only turn on when stopped, idling in traffic for 5+ minutes, and it should turn on for about 30 seconds-1 minute, turn off again, and be good for another few minutes. Those under car coolant tubes and having the radiator separated from the engine compartment (2 seperate spaces to draw heat from the engine, and the air across the coolant pipes), asking with the higher fluid volume of the Fieros system, make for a fairly efficient system when everything is operating properly. Have you replaced the water pump ever? If it was replaced with one with a plastic impeller, that could slip and give you basically no fluid flow. Also the front air dam from an Aero nose is a necessity for the Aero nose, as that is where the air comes from to go through the radiator. Lower temp fan switches and what not are not your issue, if you are moving, you should not "overheat" (Fiero gauges are also notoriously wrong, if the gauge reads in the red, that is literally meaningless, get a scan tool to get the ECM temp reading, or use a physical thermometer) actual overheating is to the point where it is puking coolant out of the overflow reservoir, in liquid and steam form.

[This message has been edited by 1985 Fiero GT (edited 06-07-2024).]

cartercarbaficionado JUN 07, 11:02 PM

quote
Originally posted by 1985 Fiero GT:

It should easily stay cool without the fan, the fan should only turn on when stopped, idling in traffic for 5+ minutes, and it should turn on for about 30 seconds-1 minute, turn off again, and be good for another few minutes. Those under car coolant tubes and having the radiator separated from the engine compartment (2 seperate spaces to draw heat from the engine, and the air across the coolant pipes), asking with the higher fluid volume of the Fieros system, make for a fairly efficient system when everything is operating properly. Have you replaced the water pump ever? If it was replaced with one with a plastic impeller, that could slip and give you basically no fluid flow. Also the front air dam from an Aero nose is a necessity for the Aero nose, as that is where the air comes from to go through the radiator. Lower temp fan switches and what not are not your issue, if you are moving, you should not "overheat" (Fiero gauges are also notoriously wrong, if the gauge reads in the red, that is literally meaningless, get a scan tool to get the ECM temp reading, or use a physical thermometer) actual overheating is to the point where it is puking coolant out of the overflow reservoir, in liquid and steam form.



if you've followed along my journey of this car you would know that it's boiled over a few times and I've done headgaskets and a new metal impeller water pump. I cannot find an aero nose air dam so I was going to modify the bumperpad kind to try and help force air into the rad a little more and this fan litterally doesn't pull air through the rad at random and the fan won't run on its own at all. so the fan switch is not working correctly since if I ground the wires it works just fine
anyways I was going to do the much larger fan mod and some other things to help alleviate the overheating since I haven't added the extra load of it's ac compressor and its already overheating within minutes of its fan being off in traffic so clearly it needs the extra help before I go adding more thermal stress to it
cartercarbaficionado JUN 07, 11:22 PM

quote
Originally posted by armos:

Fan switches haven't been reliable for me.
If your car is AC equipped then you can force the fan on by turning on the AC, even if the AC doesn't actually work (mine doesn't).
If it can't easily stay cool with the fan on, then you have a mechanical problem with the cooling system.


that's what had been working but the system is having an issue that is related to the radiator fan
1985 Fiero GT JUN 07, 11:26 PM

quote
Originally posted by cartercarbaficionado:

if you've followed along my journey of this car you would know that it's boiled over a few times and I've done headgaskets and a new metal impeller water pump. I cannot find an aero nose air dam



Ok, yeah I've read quite a bit of this "Tangerine of a Fiero", but I don't remember exactly what's been done to it. Really is a troubleshooting nightmare haha.

The Fiero store has the Aero air dam for sale.
cartercarbaficionado JUN 07, 11:34 PM

quote
Originally posted by 1985 Fiero GT:


Ok, yeah I've read quite a bit of this "Tangerine of a Fiero", but I don't remember exactly what's been done to it. Really is a troubleshooting nightmare haha.

The Fiero store has the Aero air dam for sale.


oh then I'll have to purchase that and every single thing to go along with it then so I'll add that to the budget
and it's alright, this car is legit a nightmare but it's so fun to throw into a corner and nail the throttle and just let it sing
armos JUN 09, 08:38 AM

quote
Originally posted by cartercarbaficionado:
this fan litterally doesn't pull air through the rad at random


Doesn't pull air? I don't understand. Is the fan running or not? Is it slowing down?


quote
that's [using the AC switch] what had been working but the system is having an issue that is related to the radiator fan


I'm trying to understand what does and doesn't work.
When you use the AC switch, does the fan always come on?

When the fan is on, does it keep the car cool?


I understand that the automatic fan switch (based on coolant temperature) doesn't work. But I'm unclear whether anything else is wrong.
Yellow-88 JUN 09, 09:50 AM

quote
Originally posted by cartercarbaficionado:

finally got some hot days and it's been 85 degrees and it finally started to overheat again and make some interesting noises so I'm not sure what's going on but I'm gonna try that better fan mod and the low temp fan switch to try and remedy this again. also getting a bumperpad air dam to graft to the aero style front end



What "interesting" noises? What symptom details are you calling "over heating"?
82-T/A [At Work] JUN 09, 10:34 AM

quote
Originally posted by cartercarbaficionado:

if you've followed along my journey of this car you would know that it's boiled over a few times and I've done headgaskets and a new metal impeller water pump. I cannot find an aero nose air dam so I was going to modify the bumperpad kind to try and help force air into the rad a little more and this fan litterally doesn't pull air through the rad at random and the fan won't run on its own at all. so the fan switch is not working correctly since if I ground the wires it works just fine
anyways I was going to do the much larger fan mod and some other things to help alleviate the overheating since I haven't added the extra load of it's ac compressor and its already overheating within minutes of its fan being off in traffic so clearly it needs the extra help before I go adding more thermal stress to it




It's strange to me that it's running as hot as it does... and you're having so many issues with cooling.

If your car is running optimally... as in, totally perfect / new... the radiator fan should essentially never come on. I'll compare it to my 1987 Fiero SE / V6 as it ran back in ~1999. It had maybe 75k miles on it, totally stock except for hogged out manifolds, but all fluids having been changed, etc.

In ~70 degree South Florida spring weather, the car would sit in the parking spot (in the shade), running... fully warmed up, and the radiator fan would NOT come on. It would sit perfectly at about the 2/5ths mark. Only other thing I'd done is put Redline WaterWetter in there. But this is more or less what you can expect for a car that's running *perfect* ... fan should really never need to come on, even at idle if everything is good.


With the miles you have, the first thing I tend to consider / look at are (in this order):

- Bent cooling tubes (can't remember if you said you looked at this)
- Stuck thermostat (which I know you've already fixed)
- Correct thermostat caps (which I know you've already looked at)

At this point, if I don't notice anything wrong. I'll literally flush the entire cooling system... not just drain everything out, but completely flush it all out. As a poor kid, I probably didn't replace the hoses unless I needed to, but I would even take out the radiator, cap off the bottom, and fill the radiator with solvents (something like MotorMedic's Radiator Flush). I'd shake it all around and let it sit, and then shake it even more... and then flush it with a garden hose (all while, the radiator is out of the car). I'd usually see all kinds of sediment and rust come out.

I'd also get one of these guys: https://www.fleetpride.com/...ol-accessory-atd3404



... I'd use that to make sure all the fins on the radiator were totally straight and clean. If you have air conditioning, you'll want to do it on the condenser as well.


Now, important... the outside of the radiator gets as nasty as the inside does. With the radiator still out... you can use some HVAC condenser spray to clean the outside. Something like this (I can't remember the specific brand I used): https://www.zoro.com/nu-cal...r-4290-75/i/G1188056

I'd use it on both the condenser as well as the radiator.


I'd then get a high-pressure garden hose (not a pressure washer) and spray the radiator from the opposite end (from the back to the front). Basically... the radiator spends its entire life getting air going in one direction, so it builds up dirt, grime, etc... in one direction. Easiest way to blow it out is to spray water from the other side... and you'll be amazed what shoots out of there (both the condenser and the radiator).


I'd then put it all back together, and if you've checked everything here... and you KNOW you have a good head gasket... then it's absolutely got to be something like timing.


Chances are, you either have a kinked cooling tube, or your radiator is more or less clogged.