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Overheating---but why?

 
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Old 06-08-2007, 04:54 AM
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Overheating---but why?

So I've had an overheating problem for awhile now...and I can't seem to find out what it is. It doesn't overheat in the city if I drive normal, but if I shift at a high rpm, go to a high rpm in the city, it will get warm...about 225-230. When I'm on the interstate or highway is when it heats up, but only when going straight/uphill. When I go uphill it seems like the temperature rises big time. I went on a cruise last weekend through the black hills where I live, and i was only going 5-10mph, but I was going uphill for awhile, and it heated up to about 245 so I pulled over. When I go downhill at any speed and rpm, the temperature will drop to 200....new thermostat, radiator was flushed by tires plus, and I cant seem to figure out what it is.
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Old 06-08-2007, 08:12 AM
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When you go downhill, you're getting a lot more air into the radiator. This will decrease temps a bit.

Do you have a slow radiator leak somewhere? it could be any random heater hose to the coolant bypass hose(s).

One thing i can say you should look at is the thermostat ground. yes, there is a ground wire that is connected to the t-stat housing.
If not that, i'm gonna have to say to replace your thermostat with a genuine Honda one. OEM temps are around 270-280 degrees. I've had troubles with aftermarket t-stats, such as Napa and Autozone ones on my old Accord.

...also, how do you know what temps you are at? you have some sort of gauge/meter?
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Old 06-08-2007, 10:21 AM
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since you're not seeing the problem when you're going fast, the air flow is helping to cool the radiator. so... i'd check to see if you have something blocking coolant circulation... like a clog in your radiator or radiator hose.
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Old 06-08-2007, 03:08 PM
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no, I see the problems more when I am going fast, thats whats weird...so that eliminates out fans not working...ya its a checker auto tstat, and I heard go genuine honda only, but it says its a 190 degree tstat, and in town, it says at about 200, or at least usually

and no radiator or hose leaks that are visible
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Old 06-08-2007, 06:46 PM
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Originally Posted by Prelude13 View Post
When you go downhill, you're getting a lot more air into the radiator. This will decrease temps a bit.

Do you have a slow radiator leak somewhere? it could be any random heater hose to the coolant bypass hose(s).

One thing i can say you should look at is the thermostat ground. yes, there is a ground wire that is connected to the t-stat housing.
If not that, i'm gonna have to say to replace your thermostat with a genuine Honda one. OEM temps are around 270-280 degrees. I've had troubles with aftermarket t-stats, such as Napa and Autozone ones on my old Accord.

...also, how do you know what temps you are at? you have some sort of gauge/meter?
and yes, I know what temp I'm at....it'll stay around 200 for awhile, and then when it heats up it gradually goes up...normally in the city i dont have the problem but when im on a highway/interstate or a long distance uphill stretch, it'll go up and up until about 245-250 is when I pull over...but it almost seems like when it says its at 240-250 i can put my hand on the radiator cap and its not even hot....like its a false reading, but then i decided to see what happened if I just kept going, so i did, and then the overflow started spraying, so, im not sure
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Old 06-08-2007, 07:58 PM
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head gasket leak maybe, i was having the same problem, no visable leaks and heating up at the oddest times, my head gasket blew between the water jacket and the cylinder so it was loosing the water inside the cylinder, finally i took the spark plugs out and turned the motor over and it was shooting water out of the #2 cylinder the only signs i had of it was a slight studder when i would crank it up but after it ran for a sec it cleared up and ran fine
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Old 06-08-2007, 08:11 PM
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I say head gasket... I remember you being supercharged and you seem to have the symptoms of a leaking head gasket. your confident your not leaking coolant so then it must be the head gasket.
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Old 06-08-2007, 08:13 PM
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Actually, I'm N/A :) But head gasket was something I was looking into....and it would have to be an extremely small and hidden break.

This is something that the honda guru where I live posted...any new info from his feedback?

--
If it is overheating on the freeway, but not in town, 99% of time it is the radiator itself.

-An air bubble wont make it overheat only on the freeway.
-A bad thermostat would make it over heat all the time.
-A bad fan will cause overheating in town more-so than the freeway(because on the freeway you have alot more air traveling through your radiator).

---

also, sometimes my aftermarket temp gauge will take a few minutes extra to actually work...the stock gauge will start rising almost 2 bars (half way on the digital bar gauge) before the aftermarket gauge gives me a reading, and then it just shoots up to where its supposed to be.....coolant sensor(s) bad? And what exactly does a bad coolant sensor do. Does it cause overheating or just a bad reading? They both give me about the same reading.
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Old 06-08-2007, 08:40 PM
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sorry... I have a bad memory if I'm not getting a grade for it lol.

that guy seems to be right on the ball.

are throwing a coolant sensor code? check the sensor. it has a green plug that runs from the hose that comes from the radiator to the block. (plug could be black on some h22's.) check to see if its getting any constant voltage. I guess that's the easiest way to check that sensor...
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Old 06-09-2007, 03:05 AM
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No CEL at all. I know where both sensors are, but yeah I guess its just finding out if they're bad or not.
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Old 06-09-2007, 04:26 AM
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Old 06-09-2007, 04:44 PM
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Old 06-09-2007, 10:15 PM
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I say head gasket. I know from current experience. good call ace. p.s. go with a mugen t stat and fan switch.
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Old 06-10-2007, 02:58 PM
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Where would I go about finding those at? And I heard use honda tstats only
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Old 06-10-2007, 03:49 PM
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As it is, I wouldn't trust you washing my balls. And I typically let any trick hoe from OT do that.
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Reading this thread was like watching pulp fiction the first time...

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