95RedEX

Maybe we need to step back a minute... What all have you done to this car recently? I know you said your replaced the radiator cap and thermostat. You rebuilt the engine so I'll assume that's why you have a new headgasket & ARP studs. I'll assume the coolant is 5,000 miles old too and the correct mixture of water/coolant.

When I said flush the radiator, some oil change places will do it for like $50 or so. They hook up your car to a machine and runs some cleaning ---- through to get everything out of everywhere. What's gets me though is the hot and not cooling pipes.

For the life of me, I can never remember which way the cooling system flows. If one pipe isn't getting hot, it means you're not circulating coolant at all. I would almost suspect your thermostat and for the 8 or 9 bucks, I would try another, maybe something with a lower heat rating than the one you swapped in. Beyond that, if one is getting warm and the other is getting hot, I would guess that the thermostat is opening, but the pump is not circulating the water fast enough. I really don't even understand HOW the pump works and how it can fail, but it does happen...

Either that or bleed the system again. For at least 20 minutes. Keep adding and squeezing your pipes until no more air comes out. And make sure your fan works too. See where your temp is at when it kicks on. Let us know what happens.

95RedEX

I wonder if taking the thermostat out completely would show whether or not you have any internal blockage?

When you purged your system, did you turn the heat on too?

90turbohatch

Thanks for the help 95RedEX. I've got a built turbocharged d16a6. I also have a block guard which i believe could cause the car to overheat but my engine was not overheating even on hot days in the summer. It has just been happening recently. When i put the engine in approx. 5000 mi ago I put a new honda oem water pump and thermostat with a 50/50 coolant/water mixture. Since the overheating I was just adding water when the radiator was low. I decided to replace the rad cap because I have no idea when the last time it was replaced. The symptoms I had led me to believe I had a bad thermostat and possible air in the system. So i threw in a new stock temp(I believe 180 degree F.) stant thermostat and tried to bleed the system. I filled the radiator with the bleed screw open until coolant came out and closed the bleed screw. Then I started the car and turned the heat on full hot high blower and added 50/50 mix until the rad was full. I let the car run for at least 40 mins fan never came on. My heat was hot. I took the car out for a drive and it overheated in a few mins. Pulled over overflow full and fan on. Heat got cooler and lower rad hose was cold. I let the car cool down refilled rad and drove home. Car got real hot again on the way home. When I got home the fan was on and the lower hose still cold. Still no circulation. Pump? Blockage in rad? Thermostat? I took the upper and lower hoses off the rad and flushed it with a hose real good. It seemed to flow very well. Refilled cooling system and took it out for a drive. Overheated again- that was my last post. Lower hose still cold. Next day I tested both thermostats. I heated water till 190 degrees and dropped the honda one in. It seemed to open all the way. Removed the stant from my car and tested that also. It also opened. I decided to run with no thermostat. I filled up the cooling system and started the car. I let it run for alittle and the lower hose got pretty warm. I also squeezed the lower hose. I could feel the coolant flowing. Yay!!! Pump seems ok!!! Took the car out for a spin. Got on the highway and boosted a couple times. The temp gauge didn't budge. I gotta get going. I'm gonna post again later and let you know what happens. sorry so long and i hope it makes sense

hotrex

removing the thermostat will just prolong the time until you see the symptoms....

90turbohatch

you think my symptoms point to headgasket as you stated earlier? what do you think is going on?

95RedEX

Aren't block guards notorious for adding heat?

95RedEX

I was thinking about this again this morning... How are you purging the air? You should set the heater control to hot, open the radiator cap and then start the car. It really doesn't matter if the overflow is filled, but the radiator should be filled to the top. Let it run for awhile and you can try to bleed it with the bleed screw, but IMO, that thing is worthless.

While it's running, grab the radiator hoses and give them some quick squeezes to try and burp any air pockets out. You want to do this for awhile until the thermostat opens and recirculates the water in your engine (hopefully bringing some air with it). The level in your radiator is going to go down or spill over... Just keep adding and squeezing and adding until you're 100% sure that the air is out.

I'm not sure if this addresses why your lower hose is cold, but ---- it, I'm sure you don't want to take Hotrex's advice and tear your head off just yet...

90turbohatch

yeah, I believe so, but I didn't have any overheating problems for awhile. I don't think the blockguard is my problem. Also, I think it flows sufficiently. -just doesn't cool the top of the cylinder as much. here's a pic
[img height=500 width=650]http://usera.imagecave.com/ahsnowbd/DSCN0855.JPG[/img]

90turbohatch

You are right on me not wanting to rip the head off yet. It just seems to amaze me that that would be the problem. I've got arp head studs and a cometic head gasket and only running 8 psi boost. I'm sure there are plenty of people here reusing stock gaskets and used head bolts with no problem. Actually i know someone who is reusing headbolts and headgaskets with over 100k. mi and running 15 psi boost. I've tryed to bleed it how you said with the exception of squeezing the hoses. Maybe I still didn't get all the air out yet somehow. I'm gonna try again. thanks for the help

95RedEX

If it's not the HG, Hotrex owes you 5 bucks.