I have an overheating problem. First off, i have a completely rebuilt turbo h23a prelude motor. Darton sleeves, pistons, rods, headwork bla bla bla the whole 9 yards. It seems as if my engine will only overheat under boost. I have added a fluidyne radiator with FAL fans that are hotwired (permanently on), put on a new stock honda thermostat, and i still have the problem. It seems as if my coolant reservoir seems to keep filling up to the top with fluid and sometimes under boost it will fill up so much that the top will pop off and shoot fluid out. Then the engine overheats, usually after i boost .8bar+ for a few minutes. I replaced the reservoir but there is still a little bit of fluid that comes out near the top hat. One thing that happened frequently was air kept getting into the coolant lines, whenever i loosened the thermostat nut air would sputter out for a while until a constant stream of coolant flowed out. The fluidyne radiator came with a 13lb cap, stock caps are 15lb. Fluidyne told me a 13lb would be sufficient. But i had these problems BEFORE i added the fluidyne radiator along with the FAL fans that are permanently on when the car runs. I also have a check engine light that comes on when the temp reaches the middle of the gauge. I tried to get a code but it wont throw a code, instead it just blinks on off on off over and over. I know long beep = 10 and short =1, its a series of short beeps, ive counted it blink 100 times and it just kept going. I read my manual and it said the ecu going into back up mode. Also, i have no coolant in my oil. My oil is brown, not milky. Anyways, any ideas here why i am overheating and experiencing these things? I appreciate any help. Thanks guys!!!

-Anthony http://www.clemson.edu/~averma/newprelude

 

From what your saying, it really sounds like a blown head gasket. My car had the same problem. My car would run perfectly fine, until I hit boost. Once I hit boost, the coolant would come back out into the resvoir, and over fill. I took my head off, and found tiny little crack on my head gasket. I know you just rebuilt the motor, but you should check it though, from the symptoms your having, it sounds like a blown head gasket. Also check your block, pistons, cylinder walls.

 

what kind of coolant are you running? Check into the head gasket I agree with that. Oh boosting more than a minute at a time even makes mitsubishis heat up too. Use a 25 to 75water blend or just use something like redline or something similar. I use to have this problem not any more. Oh try running like dryer machine duct to your radiator if your intercooler is in front.

 

It may be your cap....maybe. The only experience with this that I have seen is my friends Integra. He bought a Fluidyne and it would overheat also. We noticed the pressure on the cap also. Fluidyne ended up getting him another cap with a higher pressure rating. He has not complained since.
Could be....

 

i dont think it would have anything to do with the radiator if it is always on...

 

I had a feeling the headgasket has went bad. How long did you drive around until you replaced it? And how bad is it to drive around with a possibly blown head gasket if you dont go around boosting? (Dumb question, i was just wondering) Also, did you have any coolant in your oil or vice versa? I bled the system again and emptied the coolant reservoir to the min level and boosted a few times to .8 bar and it didnt overheat. It overheats if i boost around for a few minutes and really get on it. Anyways, thanks for the info and let me know whats up