So I installed my electric fan setup with a radiator probe-type adjustable thermoswitch.

1.The radiator probe has been inaccurate so far(stuck in the very top by the upper neck). It shut off the fan at 80C this morning and then around 88C tonight.
Question:Can I wire in a true coolant temp sensor in place of the radiator probe? The probe has two wires. My Greddy sensor is two wires, but the sensor for the instrument cluster is one wire. Which one?

2.What is the max "safe" coolant operating temp? It got up to 100C(212F) a few times while romping on it.

 

Also, I'm using a V6 Fiero fan.

 

gonna bump this up..I wouldn't mind the Info also.

 

The inconsistency is just the way those things work. It's pretty hard to make and keep constant contact with the radiator fins. The problem is the contact with the fins changes when temperature changes.

I use one like that currently, but I stuck the bulb inside the upper hose and it is actually in the flow of the coolant. I had to put a bit of sealant over the wire to keep it from leaking.

Max save temp a matter of opinion. I have had mine up to 240F when I was first setting the adjustable thermostat, but then I also use Evans coolant so that wasn't a big deal for a short time. I would not want to see the temps over about 225F.

You can put a thermal switch in and use that. Drill and tap the thermostat housing or get an upper rad hose adapter.

 

Buy an adjustable fan thermostat and set it at 190F. The coolant temps should never go above 210F. If they do you need better ducting, better fan, or both. Might want to try 30% antifreeze, 70% distilled water with water wetter. An aluminum radiator is unnecessary on a street car.

http://www.rjays.com/Cooling/elec-fans-01.htm

 

Thanks.

 

Actually, I think the issue with those "fin probe" fan triggers is that your temp gauge (and please, ditch the stock gauge for a real, aftermarket unit) is measuring the coolant temp and the probe is reacting to the temp of the matrix core metal.

Since the fluid can shed it's heat much faster than the metal can, there is always a discrepancy.
This is probably exacerbated by the contact issues that jackchild noted, but I don't think that is the main problem.

Unless the gauge and the probe are both in direct contact with the coolant, you're not getting an "apples to apples" comparison and the two will be much harder to get in sync.

 

I was never totally happy with my adjustable temp switch until I moved the bulb to the dead center of the radiator. It seemed to run a bit better after that but was never really that great.

Putting it into the coolant flow creates a possible leak point.

The more reliable thing would be to ditch the adjustable thermostat and use a fixed temp switch. Drill and tap the water pump housing. Get a temp switch for around 92 degrees.

 

I have noticed that even with the fan switched on, the coolant temps(according to the GReddy gauge, sensor before tstat) are rising to 100C constantly.

I thought the Fiero fan was supposed to be a sufficient unit for FCs?

 

what about thermal paste used for processors? That should help seal the tiny gaps.

 

My **** ran Hot today. it was warm out here in seattle maybe 83. runs fine for 20 30 miles then it starts to rise. when i pull off and idle then it wants to cool down.. This stock clutch fan sucks.
new thermostat too.

 

Bad radiator?

I've always recommended the GM fan above others, but the Fiero came with two different styles of fan. Can you post a picture? Maybe you have the crappy 4 cylinder fan.

 

It's never bad to have your radiator cleaned and tested in the spring when it starts getting warm anyway.

 

I do have a stock radiator with some flattened fins, so that needs to be addressed.
The Fiero fan I have is very similar to the one on your writeup, Aaron. It definately came off a V6, I pulled it myself. It has it's own shroud, 5 blades.

 

An overdue update:
I switched to a aluminum Koyo radiator. I cleaned it, checked fins, and bled the system (PROPERLY).

My temps still creep up to 100C, and like before they are very erratic. Sometimes the temp will stay between 80-90C. Then while cruising at highway speeds, the temp will stay stuck around 100C??
I definately have the V6 fan.

Thermostat problem? Radiator probe needs to go?

 

Could be either, or both.
The weird thing is your highway temps, which should be the lowest but aren't.

The thermostat is a cheap easy fix and would be the first thing I'd change.
After that, the probe needs to go, replaced with a proper temp switch.