So I'm doing a complete rebuild of my Duke and I'm wondering if I should replace the thermostat 195f with the stant 180f thermostat?
I did a LOT of reading on this, and 195 degrees isn't always the best option... just because it was stock. Back in the 1960s and 1970s, most cars actually came with 160 degree thermostats from the factory. Companies starting putting 170 degree thermostats in because it made the defrost more effective, and they eventually determined that 180 degrees was more or less optimal ... it wasn't that much hotter... so no real wear on the engine and engine components, and was optimally more efficient for combustion, etc.
The idea that a 195 degree thermostat is the best thermostat for all engines just isn't true. It really depends on the kind or generation of motor. Our Iron Duke engines are basically 1970s technology, with early 80s fuel injection. The same engine (but with a carburetor and older valve design) came with 180 degree thermostats from the factory. But on the Fiero's Iron Duke...there are three temperature sensors on the engine, though one of them feeds the ECM, so it knows what temperature the engine is operating at and can properly handle running a 180 to 185 degree thermostat without creating issues.
Anyway, at some point in the early 1980s, the EPA Federally mandated 195 degree thermostats because they believed it would improve emissions. The hotter the combustion chamber, the less likely there would be any unburned fuel, etc. And, there is something to that of course... but things have changed over the years. Our fuels are different, the catalytic converters are more efficient ... if you still have that old hideous 25 pound catalytic converter in your car, replace it with one of the newer honeycomb style ones.
I wish I still had the paper... but back when I had a 1984 Fiero 2m4 SE in the mid 1990s, Florida used to have emissions testing. I had a factory cat, and I was passing, but ended up replacing it with an Ocelot from the Fiero Store because I wanted more performance. The emissions slip I got at my next testing was night and day compared to what I had before.
Anyway... if you live in cold climate (Wisconsin?) and you don't drive your car in stop and go traffic... I'd keep it at 195 degrees. But 180 degrees will be just fine... I wouldn't go any lower than that though.
Originally posted by 82-T/A [At Work]: I did a LOT of reading on this, and 195 degrees isn't always the best option... just because it was stock. Back in the 1960s and 1970s, most cars actually came with 160 degree thermostats from the factory. Companies starting putting 170 degree thermostats in because it made the defrost more effective, and they eventually determined that 180 degrees was more or less optimal ... it wasn't that much hotter... so no real wear on the engine and engine components, and was optimally more efficient for combustion, etc.
The idea that a 195 degree thermostat is the best thermostat for all engines just isn't true. It really depends on the kind or generation of motor. Our Iron Duke engines are basically 1970s technology, with early 80s fuel injection. The same engine (but with a carburetor and older valve design) came with 180 degree thermostats from the factory. But on the Fiero's Iron Duke...there are three temperature sensors on the engine, though one of them feeds the ECM, so it knows what temperature the engine is operating at and can properly handle running a 180 to 185 degree thermostat without creating issues.
Anyway, at some point in the early 1980s, the EPA Federally mandated 195 degree thermostats because they believed it would improve emissions. The hotter the combustion chamber, the less likely there would be any unburned fuel, etc. And, there is something to that of course... but things have changed over the years. Our fuels are different, the catalytic converters are more efficient ... if you still have that old hideous 25 pound catalytic converter in your car, replace it with one of the newer honeycomb style ones.
I wish I still had the paper... but back when I had a 1984 Fiero 2m4 SE in the mid 1990s, Florida used to have emissions testing. I had a factory cat, and I was passing, but ended up replacing it with an Ocelot from the Fiero Store because I wanted more performance. The emissions slip I got at my next testing was night and day compared to what I had before.
Anyway... if you live in cold climate (Wisconsin?) and you don't drive your car in stop and go traffic... I'd keep it at 195 degrees. But 180 degrees will be just fine... I wouldn't go any lower than that though.
I appreciate all the info. I do live in Wisconsin and it is my daily driver. So would a 180 in the summer 195 in the winter be a good idea? My car has previously had overheating issues although I am actively rebuilding the entire engine and refreshing a lot of old components so I'm imagining it will do a much better job keeping cool after the rebuild but still I wanna build it the best that I can. Also I'm running it with a glass pack in place of the cat and a GT dual outlet muffler in stead of the single outlet muffler.
I appreciate all the info. I do live in Wisconsin and it is my daily driver. So would a 180 in the summer 195 in the winter be a good idea? My car has previously had overheating issues although I am actively rebuilding the entire engine and refreshing a lot of old components so I'm imagining it will do a much better job keeping cool after the rebuild but still I wanna build it the best that I can. Also I'm running it with a glass pack in place of the cat and a GT dual outlet muffler in stead of the single outlet muffler.
The thing is, a 180 degree thermostat won't solve overheating issues, so you'll want to resolve whatever is causing that. I can't really say by guessing, but often times, the pipes that run under the door thresholds get crimped (people think they're frame supports and jack the car up with them). So check those...
Also, a radiator doesn't last forever, and you likely need to (at a minimum) take it out and flush out the entire thing, including washing the radiator backwards with A/C condenser cleaner.
One consideration not mentioned in this discussion is at what temperature the ECU triggers closed loop operation. Does it trigger based on operating time ( O2 sensor being warm enough) or water temperature?
My 4.9 swapped car triggers closed loop operation at 176°F, so a 180°F thermostat is out of the question for me.
Originally posted by 82-T/A [At Work]: The thing is, a 180 degree thermostat won't solve overheating issues, so you'll want to resolve whatever is causing that. I can't really say by guessing, but often times, the pipes that run under the door thresholds get crimped (people think they're frame supports and jack the car up with them). So check those...
Also, a radiator doesn't last forever, and you likely need to (at a minimum) take it out and flush out the entire thing, including washing the radiator backwards with A/C condenser cleaner.
I'm probably gonna be getting a fully aluminum 4 row soon here. I know my tubes are in good shape but I did find a hole in my thermostat housing 💀
I'm probably gonna be getting a fully aluminum 4 row soon here. I know my tubes are in good shape but I did find a hole in my thermostat housing 💀
We did the same thing... it was really hard to get the top radiator bracket on. My daughter used a dead-blow to re-shape it so it would fit the new wider radiator. I think if we had to re-do it, I might have put spacers on the bottom bracket. You'll see when you get it... it doesn't fit perfectly in like the original does.
Originally posted by 82-T/A [At Work]: We did the same thing... it was really hard to get the top radiator bracket on. My daughter used a dead-blow to re-shape it so it would fit the new wider radiator. I think if we had to re-do it, I might have put spacers on the bottom bracket. You'll see when you get it... it doesn't fit perfectly in like the original does.
I'm sure I'll have to do a little retrofitting but I'm up for it.
We did the same thing... it was really hard to get the top radiator bracket on. My daughter used a dead-blow to re-shape it so it would fit the new wider radiator. I think if we had to re-do it, I might have put spacers on the bottom bracket. You'll see when you get it... it doesn't fit perfectly in like the original does.
I had to eliminate the two rubber mounts at the bottom of the radiator, and use thin rubber mats (like from a rubber floor tile) instead. The top bracket holds the radiator very tight so I don't think the radiator is going to be bouncing on its mounts. But yeah, it isn't exactly a plug-and-play installation. The OEM-style radiator with plastic tanks seems to be out of stock indefinitely (and has been so for a few years I think) so that is what drove me to the aluminum radiator.
