ok here is the story. from begining to end.

first off..

Fans work. ALWAYS on ( toggle switch)
thermo is good ( checked in hot water on stove)
new water pump
new temp sending unit in head.


gsr block
b16 head
all BRAND new honda OEM parts inside the motor ( complete overhaul)
stock sized pistons ( no overbore)

NO WHITE SMOKE OUT OF TAIL PIPE
NO LOSS OF COOLANT
NO COOLANT IN OIL
NO OIL IN COOLANT

FLUSHED entire coolant system with a hose, including the heater core and radiator.

SYSTEM HAS BEEN BLED ON INCLINE WITH HEATER ON FOR EXTENDED PERIOD OF TIME> NO AIR IN SYSTEM!!!


car gets hot when i mash on it hard SOME TIMES.

within a 25 second span ( while under HARD acceleration) the temp will go from normal operating temp to right below the H and then back down to normal after i put it in 5 th and start coasting..

it only does it half the time.. some times i can drive it hard all around town and it will not over heat. then other times it will get hot on the pulls i do..

i KNOW it is getting hot because the overflow tank gets filled up when it gets close to H on one of those runs..

.................................................. .................................................. ....................Above is the way it is now .

earlier last week the issue was way worse and the car could idle all day and not get hot but as soon as i started down the road it would over heat. SO i replaced the water pump and bled the system hard core and replaced the thermostat etc etc and the car wouldn't even get warm hardly. i drove it 120 miles to get it tuned on the dyno, did 20 pulls on the dyno and drove it 120 miles home with NO issues of over heating...

now all the sudden it warms up before i get 2 miles down the road and will STAY at normal operating temps at highway speeds for my entire drive to work ( 60 miles) and ONLY gets hot when i really mash on it through the first three gears at least...and only then it is just every other time.

any ideas??? im about to install a new head gasket but im going to do a leak down test first since i just snugged up my headbolts from 60 to 63 ft lbds..

 

this is a dumb question but the collant is filled up all the way right.

if you did not get a new thermostat get one they are cheap

check and make sure that your radiator isnt dirty on the outside?????? thats what happens to refridgrent components i guess it couple effect car rad's

 

If you suspect head gasket check underneath oil cap from crap build-up. Drain your oil and take a look at it. This happened to me once before. Ended up having a cracked sleeve. OH and one other time when my deck was warped.

 

took the valve cover off and no crap build up . oil looks fine man. i check it constantly and it looks good... also in regards to having the coolant all the way full yes it is

the motor doesn't have more than 800 miles on it since it was in the machine shop getting a SLIGHT over bore and then once i got it in the car fully assembled and brand new i drove it for about 200 miles before i had ANY signs of any of these over heating problems.. lol same weather outside and everything..

 

how is your fan? Does it pull "good"

 

this is such an immediate surge of heat that the fan has nothing to do with it. the fan is only useful if im setting in traffic.. not when im going 120 on the highway..

but if i must answer this question then YES the fan works great and moves tons of air. lol

plus outside air temp is about 70 degrees.

i appreciate the responses so far . this is stressing me out alot so im not trying to be a dick. just trying to hear something new.

 

what else did u throw at the engine when u did the "slight overbore" ? what is the bore

 

well everything inside the motor is OEM honda parts. slightly oversized PR3 pistons. ctr cams etc etc..

nothing major. all motor car. and had no issues driving it around till all the sudden one day under normal driving it got hot and BAM i can't get it fixed...

 

are you sure its not the gauge or wiring, get a mechanical temp gauge and hook it up just to check before you go more crazy

 

wait....you only have 800 miles on it when you take it and do 20 pulls at the dyno? i never even consider that until 2500 or so miles. Honda doesnt recomend driving a new car past 5000 rpms till 4-5000 miles on it. i def would have waited before destroying a large investment like that. just my $.02

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaJDMimports &raquo;</TD></TR><TR><TD CLASS="quote">wait....you only have 800 miles on it when you take it and do 20 pulls at the dyno? i never even consider that until 2500 or so miles. Honda doesnt recomend driving a new car past 5000 rpms till 4-5000 miles on it. i def would have waited before destroying a large investment like that. just my $.02</TD></TR></TABLE>

he is fine, the motor breaks in in ten minutes. Just change the oil after the first 10 minutes and she is good ot go. AFter 500-1000 change to synthetic. The most important part of a built is tuning. If your afrs are lean you will melt pistons.

 

it has had 2 oil changes. broke it in with regular oil and just before the tune changed to synthetic.

i just found out that my fan was wired backwards so it was pushing air through the radiator to the front of the car insted of pulling it through to the engine bay.. so i am puttin the motor back together tonight and seeing if re wiring the fan fixes my retarded problem...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JOE BD-0 &raquo;</TD></TR><TR><TD CLASS="quote">

If you are going 120 on the highway, your car is trying to tell you that you indeed are an idiot and don't deserve our help or respect.....good luck</TD></TR></TABLE>

Why the hell do you car how fast he went.\

Delete what you said.

 

I had almost the exact same problem on my last crx......i would cruising on the freeway and all of a sudden it would rise to about a quarter ways from the H and then eventually would drop back down and would be fine for the rest of my drive.....I changed the thermostat and it worked for a while, but then the problem came back I was never able to figure out what the problem was either.

 

hmmmm.. as to the guy who is criticising how fast i went .. get a life. thats not the point..

ANYHOW.. i am trying one more thing tonight and ill post if it worked!

 

are there any exposed wires anywhere? my accord did this only it would do it when i turned,i had a wire that had the coating rubbed off and it would touch the body and ground out for a second and my gauge would spike then slowly come back down.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EA-THatchback &raquo;</TD></TR><TR><TD CLASS="quote">are there any exposed wires anywhere? my accord did this only it would do it when i turned,i had a wire that had the coating rubbed off and it would touch the body and ground out for a second and my gauge would spike then slowly come back down.</TD></TR></TABLE>

it doesn't spike. its a realistic rise. i checked to see what a spike looked like and it is alot more abrupt and goes all the way to the H..

 

re-wired fan so it turns correct direction now...
finished that last night. problem still not fixed.

final symptoms:

does it EASILY ( first pull) after driving on the highway for extended periods.. BUT only when i mash through gears HARD..

fills up coolant resivoir

bottom radiator hose COOL.. top one HOT...

 

thermostst not opening all the way?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx2nr822 &raquo;</TD></TR><TR><TD CLASS="quote">I had almost the exact same problem on my last crx......i would cruising on the freeway and all of a sudden it would rise to about a quarter ways from the H and then eventually would drop back down and would be fine for the rest of my drive.....I changed the thermostat and it worked for a while, but then the problem came back I was never able to figure out what the problem was either. </TD></TR></TABLE>

lol I have the same exact problem, but then again my radiator is pretty mashed.. missing about 2/3rds of the fins since they're all falling out and corroded.

 

I had a similar problem and did most of the tests you did as well, aside from pulling the thermostat. I even got the Mugen Rad cap to raise the boiling point. Prob was fixed for a while, then i would get spikes.

It turned out the head was warped. A local mechanic is swapping a replacement ZC head and some other stuff as I was going to Hawaii.

 

ok leak down test came out perfect...

im taking the thermostat out tonight and putting it back in with the spring and center section removed..

 

ok i did that thing with the thermo and made some observations while i was bleeding the system.. after i bled out all the big air bubbles i revved the car up several times and watched the coolant in the radiator. some little bitty bubbles came up every time i revved it up... but they were just the smallest possible and just swirrled around in there a little.. hardly noticeable.. the more and higher i revved it the more little bubbles came up and the dirtier the coolant looked... it also had some little black specks of something in it from time to time also..

 

the water pump turning is what causes the small bubbles,the coolant may just be curning up all of the stuff that you dont normally see when the caps off.im not sure what the black specks are.try taking the water pump off and see if the fins on it are rusted, that can cause poor water flow.

 

its a brand new honda water pump.

o and your right about the little bubbles..

im going to get new coolant hoses this weekend and see what that does..