Thermostat

[the_integra_man]

Hi,

Just wondering if someone can tell me whether I need a new one. I have two integras, one is a RS and the other is a R. The RS seems to run at normal operating temperature most of the time cooling down slightly when on the highway or on a cold night. It stays around the half-way point for the temperature guage. The type r however seems to go a lot lower than this.. I'm not sure if it is because it cools more efficiently or if I am getting a bad reading (maybe need new thermostat?). It will work its way up to the halfway point if I am sitting in traffic or stopped at a light or something but when I get on the highway the temperature guage goes to around 25%, sometimes even less... Any thoughts?

[beastnatch]

Do you have any coolant treatment type of fluids mixed with your coolant/water mixture (like water wetter or purple ice)? Different thermostats are rated to open/close at different temps, usually lower if you get into the high performance oriented ones. Just a couple of thoughts.

I'm not sure if the operating temperatures are any different (or not) on the two engines. Someone here might have some input on that.

[coolhandluke]

The operating temperatures should be the same. Full operating temperature should be just below the halfway mark, weather it is a brand new engine or 155k. If the car isn't fully warming up or cools down when the car is moving, the thermostat is probably bad. Honda designed them to fail shut to prevent engine failure from over heating. You could still be causing damage if the engine isn't reaching full operating temperature, so I would recommend changing the thermostat asap. It's a cheap and easy fix. $14 for the thermo, $12 for coolant, $4 for RTV sealant, and go to town.

[the_integra_man]

Those were my thoughts... I just wanted to make sure before I threw away money for nothing. Thanks!

[citrus3000psi]

usually lower if you get into the high performance oriented ones.

Its actually higher temps for performance, heat = power.

[beastnatch]

usually lower if you get into the high performance oriented ones.

Its actually higher temps for performance, heat = power.

Pretty sure it's the other way around. Here are a couple of excerpts from inline four regarding a couple of the more well-known ones out there...

The Mugen thermostat opens up at a lower temperature than a factory unit allowing the coolant to flow through your engine sooner which reduces coolant temperature.

The Spoon thermostat opens up at a lower temperature than a factory unit allowing the coolant to flow through your engine sooner reducing coolant temperature.

[citrus3000psi]

Marketing gimmick...sorta...

Getting coolant to the block to help with reliability, not with power.

Heat makes things atomize faster, like fuel...

[PhucYu00]

I've had a few B18c's that took almost a half hour to warm up (not any fun in colder weather) replacing the thermostat immediately solved the problem both times. As well as heating up much quicker and staying at a good operating range..my gas mileage improved as well.
While I'm taking up space...my full-race GSR runs a little hot, so I put a 180degree tstat in it and it stays much cooler

[coolhandluke]

Honda designed the thermostat's to fail open. When they fail (open) the coolant starts circulating the block before the block is fully warmed up, so it takes longer for the block to warm up.