NOOdS

my swap was done in OCT 2009. i replaced the timing belt, water pump, and thermostat. it ran fine, i even took it to the track a couple times. never had an issue with overheating. i noticed it burning oil, then i had a rebuilt done in FEB 2011. during the rebuild, i had put in itr pistons, jdm itr headers, injen cai, skunk2 mani, skunk2 tuner 1 cams. ive put on 1500 miles to break it in before i opened up the throttle. i still use the same radiator i had on the civic, its not oem, but i never had an overheating problem before the rebuild. ive noticed it only overheat when im doing 80mph or over, when i drive normally in the city or freeway, it doesnt overheat. ive tested it up to 70mph and its fine. ive tested my fan, and it works fine, but when my car does overheat, the temp would go down when the car is moving, and i notice my overflow bottle is filled to the top and splashes all over my intake. the radiator was tested, and theres no clogs. my car is fine if i drive the speed limit, but whats the point of having all these parts on and i cant even take it above 80mph without it overheating. please dont flame on here about the speed. everyone builds a fast car for a reason. is there something wrong with my setup? how can i fix this problem? because im out of ideas.

frankenghia

kinda sounds like thermostat maybe not opening and closing like its supposed to. Have you checked it? I have seen new ones fail.

90_EX_Civic

id say this too.

only thing i can ask is did you get any head work done? might need some water ports opened up... just suggesting

pityocamptes

Do you think it could be an issue with running lean at that speed?

godluvstegs

what thermostat brand are you running?

pityocamptes

The thermostat issue does not sound right. Its either opening or its not. Should not matter at any speed - in fact you would normally see it at lower speeds (stopped) with very little pump circulation and air movement across the block. If he is not overheating at lower speeds, I don't think it is a thermostat issue.

Another issue, besides high speed lean conditions, is perhaps your radiator is too small to distribute the heat away with higher temp speeds, increased water flow, at higher speeds thus not allowing the block to cool off... since the higher temps would basically keep the thermo open constantly.

NOOdS

i have an oem thermostat from acura. ive only had it on for a yr and some months. do you guys think the thermostat would go out that fast? i didnt change the thermostat timing belt or water pump when it was rebuilt. overheating started after the rebuild.

pityocamptes

Are you overheating at any other speeds other than the 80 mph+? If not it does not sound like a thermostat issue. If it was a thermostat issue you would be overheating at ALL speeds, regardless. It sounds like either high speed lean conditions or your rad is not cooling the engine off fast enough at higher speeds/temps. Perhaps caused by the after market improvements - it may be running lean due to less fuel?

frankenghia

If it was running that lean wouldn't it throw a lean code? Are you sure the builder used the correct head gasket? Im just throwing out some ideas.

frankenghia

Also.... if your t-stat is stuck open, at higher speeds the car can't cool the coolant fast enough.

NOOdS

only overheat at 80 mph+ but not while im driving, when i come to a stop, the temp shoots up.

at normal speeds, the temp stays normal.

how would i test if im running lean? i do get better mpg even with the upgrades. i used to get 28 mpg, now i get 31 mpg.

pityocamptes

Ok, so it does overheat at STOPS. Correct? Is the upper hot and lower hose cold? if so its your thermostat. Otherwise are you sure that the temp sensor is working, along with the fan? I assume your rad is in good shape and not plugged? Its probably not a lean burn condition. I did not reailze it happens when at idle which means no air transfer through the rad and no coolant cooling...

NOOdS

if i drive at normal speeds, then temp is normal even at stops.
if i drive at 80mphs +, it doesnt overheat until i come to a stop. does that make more sense?

im not sure on the temp sensor, but the fan does kick on. radiator is roughly 3 yrs old and still in good shape.

pityocamptes

Ok, so if you are driving down the road at 90 mph for, lets say 20 minutes, it would NOT overheat during this time? It would ONLY overheat as you started to slow down and approach a stop sign, etc.?

NOOdS

correct.

i know you might tell me that its my fan, cause when im actually driving, the temp drops to normal temp.

ive tested the fan by having it parked and letting the engine idle until the fan kicks on. and it does, i know the fan works.

NOOdS

oh and i forgot to mention, when its overheating...i popped my hood checked my fan and its blowing but it seems like its not enough to cool down.

pityocamptes

You know it actually sounds like your thermostat is stuck open or your running it without a thermo stat. What does the lower and upper hoses feel like temperature wise?

NOOdS

top is hot and the bottom is cooler.

ill probably have to check that out then, maybe it got stuck open. thanks

pityocamptes

Well, that actually sounds normal as far as hose temp goes...

hyperblu

check for air in the system

NOOdS

i know this is not the problem, if theres air in the system...itll overheat no matter how fast im going.

im pretty sure other people are running more aggressive parts than i am with their stock half sized radiator with no problems. so i dont think my upgrades would be the issue. maybe ill just check out the thermostat, then maybe change out the radiator if it doesnt cool down.

pityocamptes

I would venture to say its either the thermo stat or your rad. On my non honda vehicle, I put an aggressive engine in, and found I had to go with a bigger rad over stock as it was not cooling down like it should have. I ended up using a Summit Hut aluminum racing rad and it actually cools better than the stock copper (dating my vehicle, hahahaha)...

hyperblu

Incorrect. In my cavalier, my water pump was leaking pretty rapidly and as the coolant would get low, air would enter the system (bad reservoir cap). As long as I had a good amount of air going through the rad it would be fine, but as soon as I would slow down or idle, it would start rising until I topped off the coolant.

Kohen

I'd say blown head gasket. Maybe do a compression test.

hondaOchibi7

Ok when you go 80+ then come to a stop and it begins overheating, does the temp come back down after a while of normal driving? If it does Ill say its just the small radiator taking a while to keep dissapating the heat without 80+ mph wind helping it.