The fan switch in my '88 doesn't come on until the engine hits about 220 on the temp gauge. Is this normal? I don't like it to be that high, but maybe it's for emissions. I have heard that the Corvette switch will fit the engine and it will bring the fan into play at a lower temp. Does anyone know if this is true? If not, can anyone recommend a replacement that will bring the fan into play at a lower temp? If I have to, I will run the engine with the new switch until I have to get smogged and then put the old switch back in.
The low temp fan switch shouldn't affect your smog test. If you use a 195 thermostat, the car will run in its proper heat range. The low temp fan switch has the effect of turning on the cooling fan before temperatures get critical. You can do the same thing by pressing any of the AC function buttons which will turn on the cooling fan at any temperature.
The low temp fan switch shouldn't affect your smog test. If you use a 195 thermostat, the car will run in its proper heat range. The low temp fan switch has the effect of turning on the cooling fan before temperatures get critical. You can do the same thing by pressing any of the AC function buttons which will turn on the cooling fan at any temperature.
Good info. Thanks... I have a newer thermostat in the vehicle as it is, but I believe I replaced the old stat with the lowest temp stat I could get, which is, as I recall, a 165. Does that number make sense? It helped run the car cooler until the summer really heated up and then the gauge would still hit 220 before the fan came on. This was usually when I was sitting in stop-go traffic and couldn't get airflow through the radiator. Once I hit the freeway, it seemed to be ok, which makes sense to me. With the older stat, even hitting the freeway didn't help that much. Maybe it was defective, too...
195 is where Pontiac determined to be the most efficient heat range for the Fiero. That might be for most engines, too. ECM programming is set to adjust the air-fuel ratio for best power and mpg. If the engine temperature is below that, the fuel to air ratio is increased and the engine will use much more fuel. This could possibly set a Rich Burn trouble code. That couldn't be good for the catalytic converter, either.
If you had to drop thermostat temps that drastically, I would look at the coolant pipes underneath to see if they've been crushed. Also, the radiator to see if it's clogged. You may need to backflush the system. Replace the Coolant Temperature Sensor in the end of the lower manifold, just above the water pump. Be sure your gauge is reading correctly. You might replace the temp gauge/light sending unit in the corner of the trunkside head, near the #5 cylinder. Then, with the engine at ambient temperature, turn the ignition to ON without starting. The gauge should move to the 100* f mark. When in the OFF position, it should sit on the very bottom of the thermometer symbol.
If you aren't familiar with the two temperature senders, the one above the water pump has an oval head and the one in the head has a round head with a split in the side. Auto parts stores have bad info and try to sell the oval head and a splice-in harness to replace the gauge/light sending unit.
195 is where Pontiac determined to be the most efficient heat range for the Fiero. That might be for most engines, too. ECM programming is set to adjust the air-fuel ratio for best power and mpg. If the engine temperature is below that, the fuel to air ratio is increased and the engine will use much more fuel. This could possibly set a Rich Burn trouble code. That couldn't be good for the catalytic converter, either.
If you had to drop thermostat temps that drastically, I would look at the coolant pipes underneath to see if they've been crushed. Also, the radiator to see if it's clogged. You may need to backflush the system. Replace the Coolant Temperature Sensor in the end of the lower manifold, just above the water pump. Be sure your gauge is reading correctly. You might replace the temp gauge/light sending unit in the corner of the trunkside head, near the #5 cylinder. Then, with the engine at ambient temperature, turn the ignition to ON without starting. The gauge should move to the 100* f mark. When in the OFF position, it should sit on the very bottom of the thermometer symbol.
If you aren't familiar with the two temperature senders, the one above the water pump has an oval head and the one in the head has a round head with a split in the side. Auto parts stores have bad info and try to sell the oval head and a splice-in harness to replace the gauge/light sending unit.
Thanks for this information. I will check it out. My radiator is new. The transmission oil cooler side of the old radiator developed a leak on the upper connector, so I decided just to replace the whole radiator. Shortly after I did that, I started tearing into the car to replace a bunch of leaking gaskets and seals, and then one thing led to another and now I am changing out the engine and replacing it with a 3.4 out of a '94 Chevy. The engine is being rebuilt by a company that built an engine for my friend and they did a very good job. I later found out that they might be hot and cold when it comes to doing a good job. Hope I get a Wednesday engine and not a Monday or Friday build.
Anyhow, I wasn't able to drive the car when it was hot outdoors, because the weather had cooled off. So I don't know if the new radiator will handle the cooling better or not. We shall see, if I ever get my engine and get it installed.
FYI, I have the car sitting high in the air and I have been completely through every inch of pipes, lines and hoses that go from front to rear. The cooling pipes don't even have a scratch on them, and even though the connecting hosed look and feel good, I am replacing them while I have the engine out and the car in the air. I had to replace the expansion tank as there was a crack in the old one. I did that when I replaced the radiator.
Thanks again for the info...
[This message has been edited by eti engineer (edited 01-16-2021).]
I have Rodney's 185/195 switch with the 180* thermostat on all my Fieros. Passes CA smog no problem.
Thanks. Appreciate the input. I will keep the stat I have right now and see if I have any issues with smog. Hopefully not. I am thinking that with the 3.4 going in, in place of the 2.8, I may need to use a cooler fan switch anyway. I will play with it once I get the 3.4 dialed in and see where to go with it. I will pass along any information I glean as I go. I have time to play since I am retired and living well, thank God. Don't know what I would do otherwise. Things are pretty tough out there right now. It's scary.
Here are also high flow stats that are available from Stant, Mr Gasket, Meziere and others. The valve area is larger. Summit carries them.
------------------ " 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 "
