THSCC Forums

So the ITR takes a while to warm up and it's really not THAT cold out yet. It's got about 90k and is about 10 years old. So today on my trip down to Union County it was running a bit cool on the country roads cruising along at 60 mph or so. Cool as in bouncing between about 5% (0% being right on "C" and 100% being "H") and maybe 30%, which is still below a decent operating temp.

I'm going to change the timing belt, water pump & tensioner in the next month and swap the thermostat as well. My question is this, is there anything else that could contribute to a car running this cool and warming up so slowly other than a thermostat that is stuck open?

thanks!
-Matt

Where was it bought from? If bought in the deeper South, it's possible that the previous owner put in a lower threshold thermostat. I would expect though that your diagnosis is correct. - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

Matt, funny you should mention this. My new-to-me 1998 integra is doing the exact same thing. With my highway commute and the heat on it stays around 10-20% using your scale and the heat is not up to most Hondas I've been in. I immediately thought of the thermostat. I will be hopefully picking one up tomorrow and installing it sometime in the next week. I'll let you know if that fixes mine.

Also, how hot is your heat? In my case I believe the water temp really is low. However I have had the temp sensor go bad for the gauge in my old prelude. Hondas typically have two or three. Ecu, gauge, and fans all get one most of the time. It could be your gauge sensor is going bad. That's one of the two in the head under the distributor. You might be able to ohm that one out and check it.

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2001 Honda S2000 - SOLD
2012 Boss 302
2003 BMW 330i

Interesting that you mention that Aaron; it's the first northern car (Penn & VA) I've been comfortable buying though..

Mike, misery loves company, thanks for sharing. Looks like they're only $17 from Acura Carland in GA. Let me know how it goes... I guess it could be worse and be running hot.

I tryed turning the heat off this morning and it didn't make a difference though, but it's pretty warm to answer your question.

If I turn my heat off it does seem to help the temp gauge rise a little. I only say that as I have a constant 20 mile high stint where I can play with it at steady speed.

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2001 Honda S2000 - SOLD
2012 Boss 302
2003 BMW 330i

both of our b18 integras have fresh t-stats and they warm up quickly and stay hot even in cool temps. if your temp gauge isn't stable regardless of driving or ambient conditions then your t-stat is almost certainly faulty. could be the sensor too but that's significantly less likely.

Shoot the radiator with an IR gun when up to temp. Should be somewhere 180-200 depending on the t-stat. If 180-200 then bad sender. If cooler then missing or broken t-stat.

Even with as cooler t-stat the gauge reads normal. Idiot. Gauge that is

If the car has been at all molested then my guess is missing t-stat. If not, then I'd guess one of the prongs is broken. And no, nothing else I can think of would cause the problem.

I expect pics when you figure it out

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

If you have access to one, get an OBDII scanner and see what the temp sensor reading is.

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02 Focus SVT
STF 9

180 versus 195 T-stat could be the root.

Thanks guys for the feedback.. Strangely my morning commute (city driving) kept it right where it should be at about 40% once it warmed up since it was stop and go with lights and less higher speed driving (which keeps it cooler).

Interesting point Mike. I do hope there's one in there! You almost have to brace yourself for the worst when buying one of these things. Pics soon..

Shouldn't be. We've played with many different temp t-stats and the needle location when warm really doesn't change much if at all.

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

I agree. My old prelude defined the sections on the water temp gauge as "ranges" Often they spanned 40 or more degrees. The "dead zone" in the middle was another 30-40 degrees.

I'm expecting to find a stuck open t-stat, or no t-stat in my case.

edit- Honestly, I wouldn't worry that much about it, but I expect it is doing two bad things for the motor.

1. Impact on gas mileage
2. Not allowing the oil to get warm enough to get rid of moisture

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2001 Honda S2000 - SOLD
2012 Boss 302
2003 BMW 330i

Theoretically, if the motor never gets to temp, the motor runs rich and the excess fuel can "wash" the cylinder walls and prevent good piston ring lubrication. At least this is what I have heard on the internet, I find it a little hard to believe Still, there is no good reason to let a car run cool like that, and if a t-stat is broken you never know if it might stick closed, which would cause all kinds of suckage...

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

I'm hoping it's only washing the carbon off after 186k miles right now.

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2001 Honda S2000 - SOLD
2012 Boss 302
2003 BMW 330i

I had a Triumph Spitfire just like that once. Turns out the previous owner had completely removed the thermostat unit.

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Martyn Wheeler
AXing Kit's '05 Mazda 3, #29 HStock
(when The Gonzo Symphonic allows)