M-EJ1

I have a newly purchased 1991 Integra GS... this is a "project" car, fixer-upper type thing that I got for cheap.

I had to put a new radiator in it because the old plastic tanked one was cracked and leaking. At the same time, I did a coolant system flush and fixed a little leak from the upper radiator hose housing connector on the head (there was no gasket... doh.). I replaced the radiator with a new all-metal one from Performanceradiators.com, and used a new 13lb cap from the local auto parts store. I filled the radiator up, ran the car without the cap on for a while to get the bubbles out, topped off the coolant, and went for a spin.

Things were looking good until I really romped on it. Basically the car drove fine and the temp gauge stayed at about 45% all the time. On the way home after the test drive, I decided to push it a little and downshifted and took it all the way up to redline. Poof, white smoke everywhere, temp gauge skyrocketted, blew a bunch of coolant out from under the rad. cap. I drove parked it for a minute, let it idle, and the temp gauge slowly went back down to normal, and I drove it home. Thought it was just an air bubble, so I refilled the coolant and called it good.

Now, ever since then, it does the exact same thing every time I take it up to redline a couple times. For example, on my way to work, stoplights on the 60mph highway, so I rip through the gears only to see the temp gauge rising again, almost all the way to red, so I slow down, and it drops back down to normal.

What the heck is going on here? Do I still have air in the coolant system? My head has the little bleed screw on it, BUT it has been JB-welded shut by the previous owner (Maybe it was leaking?). Can I still get all the air out by just running it without the rad. cap and letting it bubble out? Do I have a blown headgasket? The car runs fairly normal otherwise, except it runs a little rich and throws a code 43 sometimes, I think due to a leaky Fast Idle Thermo Valve. I haven't really put two and two together, though I'm going to fix the vacuum leak tonight and see what happens. Compression is 175, 170, 175, 175... not too shabby at all IMO, which is why I can't believe it could be a head gasket.

Other than the high RPM temp problem, it has no trouble whatsoever with the cooling system. I let it sit idling for 20 minutes the other night and the temp gauge never changed, I can drive it as many miles as I want during the day with no troubles, highway, around town, etc. The only time the problem crops up is when I really romp on it. It has NO coolant leaks whatsoever, never smells like burnt coolant (unless it blows out of the rad. cap).

Anybody got any ideas? Thermostat maybe? Blown head gasket pressurising the cooling system past 13lbs? I'm getting frustrated, want to push the car off a cliff, it's turning out to be a money pit so far...

NJIN BUILDR

You may very well still have air in the system.You should get another housing or fix the bleeder that you have.Its very difficult and essential that the air is out.It helps to get the nose of the car as high as possible when you fill the system.Every little bit helps.This may fix the problem and its the first thing you want to do.
Glenn

M-EJ1

Sounds like a plan. I will see what I can do about the bleed screw tonight, I may just see if the honda dealership here can order me another one (closest acura dealership is 3 hours away). I'm also going to clean/adjust the FITV, and I'll see if I can get anymore air out by parking the car facing up a hill and running it with the rad. cap off.

Thanks for the tips.

M-EJ1

Alright, I managed to bleed all the air out as far as I can tell. I parked the car facing up a steep hill, and ran it until it was warmed up with the rad. cap off, some bubbles came out, I topped off the coolant, took it for a spin and the same thing happened.

So, I'm 95% sure I have the air purged out of the cooling system, what else could this be? It's perfectly fine all around town, on the highway, idling, even running through the gears quick... it only starts overheating when I really stomp on it. Tomorrow I'm going to pull the thermostat out and replace it, other than that, I can't think of anything else to try.

My dreaded thought is that this is a head gasket problem maybe? The car runs rich and sometimes throws a code 43, I actually posted another thread with some questions about that, but would a slightly leaking headgasket leak compression/pressure from a cylinder into the cooling system without it being really apparent that something's wrong in that department? I've always heard that you'll know it if the head gasket is blown, this doesn't feel like it and the motor has good compression numbers all the way around (175, 170, 175, 175).

M-EJ1

I know it's long guys, but this is starting to annoy me. Any ideas?

Cliff notes: the car overheats when I redline it, but never any other time. I've bled the coolant system, replaced the radiator, it's got a new radiator cap, etc. May be related to code 43 and running rich and misfiring?

M-EJ1

I feel like an idiot, but at the same time, I'm glad I finally got this fixed.

It was the hood prop... the clip is gone so it was just laying across the upper hose... you can take a guess at what happened when the hood was closed. At high RPM's the water pump was outflowing the restriction and building pressure in the radiator while starving the motor of coolant at the same time.

So, sometimes you just gotta check the simple things.