radiator air flow (Page 1/2)
itzikbns AUG 14, 03:47 PM
Hi there,
I have an 86 SE 2.8 manual 4 speed, on these very hot days, my water temp is high and I noticed the fact that the radiator fan has no way of blawing the air, it is facing a wall... the only opening is below, how bad is that? any known upgrades/improvements?

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Itzik

1985 Fiero GT AUG 14, 04:38 PM

quote
Originally posted by itzikbns:

Hi there,
I have an 86 SE 2.8 manual 4 speed, on these very hot days, my water temp is high and I noticed the fact that the radiator fan has no way of blawing the air, it is facing a wall... the only opening is below, how bad is that? any known upgrades/improvements?



When everything is working properly, no leaks, no kinks in the pipes, stock engine, no sludge buildup, the cooling system is perfectly adequate for keeping it cool, and only needing the fan when stopped in traffic for a significant time. On the other hand the temperature gauge is notoriously unreliable, very often reading significantly higher than it's supposed to. Even with a higher power turbo 3.4l engine, it stays around 185* (180* or 185* thermostat, I forget) and under heavy/prolonged/frequent acceleration never goes past 220, with all original radiator/pipes, and a water to air intercooler radiator taking up the entire radiator opening under the front (all air that the radiator gets has to go through the intercooler first).
Patrick AUG 14, 04:43 PM

quote
Originally posted by itzikbns:

any known upgrades/improvements?



Hood vents. Plenty of posts/threads here covering that.
cvxjet AUG 15, 12:05 AM
Things that can cause overheating; A) Does the fan actually work? A-2) The fan switch can degrade to where the fan only comes on when the car is overheating- I went to a slightly lower temp switch which completely solved the problem. (Too low and the fan runs all the time)

B) Check the pipes under the rockers- when the car is jacked, some shop personnel do not understand how easy it is to crush the coolant pipes.

C) The water pump....Some replacements come with a plastic impeller- it heats up, expands, and then slips on the metal shaft...Be sure to only install >>Metal impeller<< water pumps.

D) The Fiero >>Mid-engine<< cooling system is a bit difficult to fill- I usually fill it at the radiator cap (With the Thermo cap off), then install radiator cap, then fill at the thermostat cap, then install thermo-cap, then start and warm up engine >>Without<< the thermostat.....let cool, then remove thermo-cap and fill some more- continue this cycle until no more water is needed, then install thermostat. Air bubbles in system can cause flow problems leading to overheating.

A hood vent is a great mod- but should not be needed...if everything is in proper shape.

I drove my Fiero all over the west- Utah, Nevada, Arizona....HOT!!! and never had any overheating (Until I installed the bad waterpump)
Patrick AUG 15, 12:24 AM

quote
Originally posted by cvxjet:

A hood vent is a great mod- but should not be needed...if everything is in proper shape.



Agreed... but it is an upgrade/improvement. With the added air flow through the radiator, the rad fan doesn't need to come on as often or for as long when the going gets hot.


quote
Originally posted by itzikbns:

any known upgrades/improvements?



Lots of pictures of different hood vents in this old thread.


Another popular mod is to replace the factory fan switch, which doesn't turn on until 235°F, with a lower temperature fan switch from Rodney Dickman. He sells two types, but the one I and many others favor is the 210° on and 200° off fan switch, which is used with the factory 195°F thermostat.


quote
Originally posted by itzikbns:

...my water temp is high



How high is "high"? And what are you basing that temperature reading on? The Fiero's temperature gauge is known to be less than accurate. Unless your reservoir is puking out coolant, your Fiero may not have any problem at all.

[This message has been edited by Patrick (edited 08-15-2025).]

jelly2m8 AUG 15, 01:09 AM
I'm not opposed to anyone adding a hood vent to their car, but they should fix the over heating problem before considering adding a hood vent to solve an over heating problem.

If the car has an over heating problem, you can install a hood vent or easier remove the hood entirely, it will still have an over heating problem.

[This message has been edited by jelly2m8 (edited 08-15-2025).]

itzikbns AUG 15, 02:30 AM
thanks all for replaying, high is about 260, I have additional filling cup on the pipe that goes to the radiator in the front boot and it has water temp sensor, I think it's quite accurate, I can't add hood modifications since it's a ferrari 308 replica, I got have spare wheel, I thought about adding opening in the boot area in front of the fan and design a manifold that will evacuate the air to both wheels area.... I will first test if it's head gasket and refill the cooling water the right way with vacuum

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Itzik

Dennis LaGrua AUG 15, 04:02 AM

quote
Originally posted by itzikbns:

thanks all for replaying, high is about 260, I have additional filling cup on the pipe that goes to the radiator in the front boot and it has water temp sensor, I think it's quite accurate, I can't add hood modifications since it's a ferrari 308 replica, I got have spare wheel, I thought about adding opening in the boot area in front of the fan and design a manifold that will evacuate the air to both wheels area.... I will first test if it's head gasket and refill the cooling water the right way with vacuum




First make sure that the proper coolant fill procedure was followed. If a vacuum test of the cooling system is done and the problem is determined to be a head gasket failure as the cause of the overheating problem; you can purchase some very good sealers that will fix the problem quickly although it might be temporary and not long lasting. A friend had this problem on his V6, and followed the procedure to use a product called "Bars Leaks" to fix it. That was three years ago and all is still fine. While a head gasket replacement would be the best alternative, head gasket sealers do buy you time.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 08-15-2025).]

Patrick AUG 15, 04:12 AM

quote
Originally posted by itzikbns:

...and refill the cooling water the right way with vacuum



I'm not sure what you're referring to... "with vacuum".

Here is the procedure I follow to fill a Fiero's cooling system.
olejoedad AUG 15, 07:00 AM
Does your 308 replica feature the Fiero air dam under the radiator support?

The air dam is essential for proper airflow through the radiator.