Coolant temp
Thread Starter
Teching In
Joined: Nov 2012
Posts: 6
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Coolant temp I recently got a 98 formula firebird and just now noticed that when parked and idling the temp gauge goes up to a little past 210 before it starts to drop. I hooked up a scanner I have and it shows the coolant temp goes up to 232 before it starts to drop. So, my question is, what temp are these cars supposed to run at? Also, why does my gauge read different than my scanner? Sorry for the stupid questions but Im a noob
mine with a stock thermostat runs under 200 max during city driving(usually in the low 190's) and in the 180s when on the highway. Im reading temps through the pcm on my scan gauge.
Id check that your coolant is good and full and that your fans/thermostat are working because those temps are pretty high
Id check that your coolant is good and full and that your fans/thermostat are working because those temps are pretty high
TECH Resident
Joined: Oct 2008
Posts: 801
Likes: 1
From: Anaheim Ca.
mine with a stock thermostat runs under 200 max during city driving(usually in the low 190's) and in the 180s when on the highway. Im reading temps through the pcm on my scan gauge.
Id check that your coolant is good and full and that your fans/thermostat are working because those temps are pretty high
Id check that your coolant is good and full and that your fans/thermostat are working because those temps are pretty high
I was wondering why you stick with stock thermostat, and are not on the 160 degree bandwagon like everyone else? Normally my car runs below 200 fully warmed and slightly over when i drive hard in the summer.
TECH Resident
Joined: Oct 2008
Posts: 801
Likes: 1
From: Anaheim Ca.
just never changed it out lol. even when I did my engine swap and had the water pump off, it never really crossed my mind to change out the tstat. the highest temp iv ever seen in my car was 230 and i shut it down in a parking lot because my radiator cap cracked and coolant exploded everywhere. that was a shitty experience lol
Normally my car runs below 200 fully warmed and slightly over when i drive hard in the summer.
Normally my car runs below 200 fully warmed and slightly over when i drive hard in the summer.
Yeah, you'll see worse gas mileage with a lower temp thermostat. If the car isn't tuned for the thermostat, there's really no benefit. In fact, it can be harmful on a stock engine due to the longer warm-up period when the t-stat opens at a lower temperature
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What are the conditions of where your car is at?
Mine used to run to 230s then drop in summer time. This was with stock t stat and stock fan settings. This was always the norm with my car in summer conditions.
Mine used to run to 230s then drop in summer time. This was with stock t stat and stock fan settings. This was always the norm with my car in summer conditions.
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Brett Foote
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
232°F can be a perfectly normal coolant temp with stock fan settings in hot weather with the A/C running in traffic. The dash gauge is not completely accurate, even on the '98 models (which are actually more accurate than the '99+). Stock fan settings can allow coolant temps to reach as high as 235°F before triggering the high speed fans. Stock fan settings are as follows:
Low speed on/off: 227°/218°F
High speed on/off: 235°/228°F
So as you can see, they are programmed to run rather hot from the factory.
Some people like a 160°F t-stat and a cold engine. Unless the setup is extreme/forced induction, I see no benefit to this for an LS1. Lots of info on both sides of this debate if you want to do a search. I know I've posted about it in great detail many times over the years.
Low speed on/off: 227°/218°F
High speed on/off: 235°/228°F
So as you can see, they are programmed to run rather hot from the factory.
Some people like a 160°F t-stat and a cold engine. Unless the setup is extreme/forced induction, I see no benefit to this for an LS1. Lots of info on both sides of this debate if you want to do a search. I know I've posted about it in great detail many times over the years.
Thread Starter
Teching In
Joined: Nov 2012
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My car is completely stock as far as I know and it was around 50-60 degrees outside when I was reaching this temperature. I actually just did a coolant flush and put in a new 186 deg. thermostat. I followed the instructions on installuniversity and after bleeding the air out of the system I decided to plug in my scanner and see how the temp on the scanner compared to the temp gauge on the car. Since 210 is the middle of the gauge on the car I figured everything was good, but after seeing what the scanner said I was kind of worried.
I will check to make sure nothing is blocking the radiator and verify the fans are coming on at the right time. Do you guys think I should pull the thermostat and check to make sure it is opening at the right temp? Thanks a lot for the help so far
I will check to make sure nothing is blocking the radiator and verify the fans are coming on at the right time. Do you guys think I should pull the thermostat and check to make sure it is opening at the right temp? Thanks a lot for the help so far
Joined: Nov 2001
Posts: 34,623
Likes: 2,541
From: Schiller Park, ILL Member: #317
My car is completely stock as far as I know and it was around 50-60 degrees outside when I was reaching this temperature. I actually just did a coolant flush and put in a new 186 deg. thermostat. I followed the instructions on installuniversity and after bleeding the air out of the system I decided to plug in my scanner and see how the temp on the scanner compared to the temp gauge on the car. Since 210 is the middle of the gauge on the car I figured everything was good, but after seeing what the scanner said I was kind of worried.
I will check to make sure nothing is blocking the radiator and verify the fans are coming on at the right time. Do you guys think I should pull the thermostat and check to make sure it is opening at the right temp? Thanks a lot for the help so far
I will check to make sure nothing is blocking the radiator and verify the fans are coming on at the right time. Do you guys think I should pull the thermostat and check to make sure it is opening at the right temp? Thanks a lot for the help so far
T-stats only regulate a minium temp. Max temp will be regulated by cooling system capacity and airflow (or fan settings at idle/slow speeds).
Did you take any readings while driving at constant speed for some time?
Thread Starter
Teching In
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I went on a drive for about 25 minutes tonight and the temp stayed between 192-194. The outside temp was 40 deg. After the drive I let it idle and the temp went up to about 230 and the fans kicked in and cooled it to 212. So I'm thinking maybe the low speed setting might not be working. I'll have to look into how to test that out tomorrow. Thanks again for the help
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
I went on a drive for about 25 minutes tonight and the temp stayed between 192-194. The outside temp was 40 deg. After the drive I let it idle and the temp went up to about 230 and the fans kicked in and cooled it to 212. So I'm thinking maybe the low speed setting might not be working. I'll have to look into how to test that out tomorrow. Thanks again for the help
Sounds like the fans are working as well. 230° is only 3 degrees above the cut-on temp for the low speed fans, and it's not uncommon for the temp to rise a bit before airflow from the fans can bring it back down.
If it dropped all the way from 230° to 212° while sitting idle, then the fans are definitely working (and most likely at low speed since high won't engage until 235° and would shut off at 228°).
IMO everything sounds normal.
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
OP said he installed a stock 186° t-stat (actually they are 86°C/187°F), which will maintain about 190-194° at the coolest during steady low-rpm cruise in cool weather. That is exactly in line with his temps.
Things are going to get hot at idle, even when it's only 40-60° outside, since there is no airflow until the fans kick on. And stock fan settings are programmed to keep the engine hot under those conditions. Stock fan settings are posted above.
Things are going to get hot at idle, even when it's only 40-60° outside, since there is no airflow until the fans kick on. And stock fan settings are programmed to keep the engine hot under those conditions. Stock fan settings are posted above.
