temp gauge reading cold

I just picked up a 2000 LS 5 speed tonight (love it!!!) and was noticing on the way home that the temp gauge seemed to run very cool. It hovered around the 2nd or 3rd line at the very bottom of the gauge. If I wound the motor out a bit, the gauge creeped up a little but then would fall back to the bottom. I don't think it ever left the bottom 3rd of the gauge.

The ride was about 25 minutes of some stop and go and some back roads. The temperature outside was about 60 degrees.

I thought I read somwhere that the integra gagues registered normal temp sitting at about 1/3 from cold, but I wanted to confirm. Mine seems to like to sit below that right at the bottom. Bad thermostat possibly?

I haven't had a chance to dig around yet and check everything out, I just did not want to mess around if there was a cooling system problem.

I appreciate any help, thanks!


Unregistered User
it COULD be your thermostat... doesn't mean it is.

does the temp actually come off of the cold marker at all?
With the car being 9 years old it probably wouldn't be a bad idea to replace it anyways.


Super Duper Moderator
I'd install a new thermostat, see if that fixes the issue. It's an easy and inexpensive fix you can do yourself. The temp guage should normally read just below the halfway point when the car's at full temp, like at the 45% area.
im pretty sure the temp sensor is on the motor side of the thermostat meaning if the thermostat was bad it would be reading hot from not getting coolant flow...and if its not completely bad then it would still be reading hot due to the motor not getting good coolant flow to keep it cool....but thats a good place to start considering i have seen guys eliminate there thermostat so the coolant is constantly running through the motor keeping it from reaching normal operating temp and causing the motor to run cooler.


New Member
Bad thermostat my friend. I had the same issue and replaced it 3 days ago. Runs like a champ now! Like TegSox said, "The temp guage should normally read just below the halfway point when the car's at full temp." If it goes over half way you're getting hot!!


Super Duper Moderator
When a thermostat goes bad, it's either getting stuck in the open position (causing coolant to flow constantly through the radiator, never letting the engine itself get up to full operating temp), or the closed position (never allowing coolant through to the radiator, which will keep heat in the engine) or part way in between one of the two. Sounds like yours can't close all the way, jackacc. But hey, it's way better than it not opening enough! lol
I had a '89 Corolla with a bad thermostat a few years ago. It finally went all the way bad on me one day and got stuck closed. My temp guage nearly pegged all the way hot. I luckily made it home, I popped the hood, I could hear the coolant boiling inside the engine (I could hear something boiling inside the engine). The sucker probably would have siezed if there wasn't a -25 wind chill factor that day.
Thank you for all the replies. I thought it might be the thermostat but thought it could be a faulty sensor or gauge too.

Today on my commute in, the temp needle was right around 1/3 on the gauge while I was sitting at a light, then as I was going, it dropped all the way down to C and pretty much stayed there the whole time. It crept up a little bit here and there but for the most part, stayed at C.

It was about 44 degrees here today but that should not matter that much, it should still maintain normal operating temp right?

I have done a little work on motors before but nothing crazy. I have changed a thermostat in my old Jeep wrangler which was cake since the engine bay is so open. I did look at the link at the top of the page showing how to do the thermostat but it did not show exactly how it goes in. I will probably be able to figure it out.

Any other tips before I attempt it? Should I get the part from Honda or will Autozone suffice? Should I have the cooling system flushed out while I am in the process? I thought I heard that sometimes when you flush the system, junk gets stuck in the thermostat and can mess it up, so if I have it flushed, I can then replace the T-stat after?

Will I hurt the car driving it like this? It would definitely be worse if it was stuck closed, haha. I have been there before too!

Thanks again for the help!


Super Duper Moderator
When everything's working right in the cooling system, it should read the same full normal operating temp at all times in any condition. Now let me bring up a situation for the nitpickers where the guage may fall: If it's cold as fuck out, you sitting still just idleing, and you have the heat cranked, the needle may creep down a little.
A generic thermostat from a parts store is fine, you don't need to go OEM and get raped. Flushing is a good idea, maybe also you should replace the 2 main radiator hoses. Generics will work fine there, too. It'll be like $25 for both hoses and new hose clamps.
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Cool, thanks. I'll pick up a new T-stat this weekend if I have a chance. I was reading a little more about the repair and it looks like I have to locate and remove a drain plug on the engine block to drain the coolant in addition to the rad plug. Then the thermostat is located in a housing at the end of the lower hose.

The only part I was not clear about was when I am refilling the system, I have to get all the air out. I think I just fill the system (and maybe the overflow tank too up to the max fill mark), start the car with the cap on onr click, and there is a little bleeder valve near the upper hose I need to let air out of? That is what I was not sure about. I never had to do that on my Jeep, I just filled it, left it running with the cap off and added coolant once the system burped and the level went down.

I will get new hoses as well while I am at it I think. How do you flush the whole system though? Is it as simple as running distilled water through the rad and out through the drain plug? I think it is more complicated to flush out the whole system right? Should I bring it to a rad shop for that?

I don't know what happened, but he temp gauge is now reading at about 1/3 up on the gauge consistantly now. I have driven it a little harder the last couple days and played with the heat and AC a little but that is about it.

It stays right around 1/3 the way up the gauge like I thought integras were supposed to do. Could the T stat have been stuck open from sitting around for months without being driven and now it decided to work again?? I have no idea, but I am not complaining! The temperature was higher today though (like in the 60's as opposed to the 40's and 50's the other days) I don't know if that has something to do with it?

I'll keep an eye on it obviously but it appears to be functioning now.

Maybe my car is like Stephen King's "Christine" and it fixes itself :)


Super Moderator
Could the T stat have been stuck open from sitting around for months without being driven and now it decided to work again??
That is possible, but it means it will probably completely crap out soon. Although the warmer temps could have just help you get a little warmer

Just replace it. Thermostats are cheap anyway. They are like $10-$20 bucks unless you want to drop $80 on a Spoon thermostat for no reason
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