HELP! 1999 Civic LX Running Hot Out of Ideas!!!!!

[civic2000sivtec]

I really need some help guys! I just bought a 1999 honda civic sedan lx automatic with 128k. Only upgrade is a Spectre cold air intake. The car is for my wife, so she comes home the first day driving it and says that it starts to get hot when she is going up hill. So of course I did the basics, flushed radiator with Prestone radiator flush, replaced thermostat and replaced upper and lower radiator hoses. So I get in the car and take it down the road with a/c on. I start going up a hill, the tranny drops a gear and the temp gauge starts to climb. I let off the accelerator and it slowly starts to cool down after I top the hill. So I hit the next hill, start to climb the hill, the tranny drops a gear and the temp starts to climb. I turn off the a/c button and no change, then I turn it from cold to hot and the temp starts to drop while still climbing the hill(It was a very long hill). So I try to repeat what happened. Turned around and started up the hill with the knob dialed to cold. Start up the hill and it starts to get hot, switch it to hot and immediately starts to drop to normal. I have no water in the floor boards so that should knock out the heater core. The electric fans come on and off. The only time it gets hot is going up a hill with the knob on cold air whether the a/c is on or not. If you turn the knob to hot air it automatically starts going back to normal. I need some ideas guys. This is my wife's daily driver and she drives 40 miles one way to work. HELP!!!!!!!!!!!

 

[2slo4u]

Did you properly bleed the system?

 

[civic2000sivtec]

Only thing I did was after I filled up the radiator I started the car, turned heater on hi with radiator cap off and overfill cap off. I finished topping off the radiator and let it run at normal operating temp for about 15 minutes. Is there something else I need to do to bleed out the air?

 

[2slo4u]

Nope that's the bleeding process. Hmmm

 

[motozachl]

Forgot to burp the system buddy. Squeeze all the coolant hoses to loosen all the trapped air bubbles while running it w.o the cap again

 

[civic2000sivtec]

k. just got off of work and gonna try that now. cap off, squeeze on hoses while car is running at normal temp. back in 30 minutes!

 

[civic2000sivtec]

So I took off the radiator cap and started the car and when it got to normal operating temp I worked the hoses toward the radiator like you do to a tube of toothpaste. I did the upper, lower and the two going to and from the heater core. Still no luck. I still can't even fathom what else it could be. But this maybe another clue, not sure if it's related but I did the sea foam treatment and noticed the white smoke coming from the manifold area. I took off the cover and found a crack from the o2 sensor bung back down to the first weld downstream on the manifold. It appears to be small so I tried to fix it with some high temp jb weld like stuff made for upwards of 2100 degrees. I followed the directions and it came out crumbly. Just thought that maybe that crack in the exhaust manifold may have been related but not sure. Come on guys, keep the ideas coming!!!! It only happens when the air selector temp is on cold and when the engine is under load.

 

[gugiey]

nvm.

 

[motozachl]

Re-read the OP. It sounds more that the coolant isn't cycling through the system properly. When you turn on the heat its like adding a secondary mini radiator thus the engine will cool down a little bit. This actuallly saved me once in which I was stranded with a bad leak in the system, cranked on the heat and it kept the temps down manageable to drive to an auto store. I am thinking that perhaps the water pump is intermittantly working, or some sort of clog around the switch valve that runs to the heater core

 

[TokyoSkies]

Re-read the OP. It sounds more that the coolant isn't cycling through the system properly. When you turn on the heat its like adding a secondary mini radiator thus the engine will cool down a little bit. This actuallly saved me once in which I was stranded with a bad leak in the system, cranked on the heat and it kept the temps down manageable to drive to an auto store. I am thinking that perhaps the water pump is intermittantly working, or some sort of clog around the switch valve that runs to the heater core

I think motozachl here is onto something. My old 'teg used to overheat randomly, I'd run the heat, and it'd cool down quickly. It turned out my water pump was intermittently seizing. Check the water pump/gasket!

 

[civic2000sivtec]

So water pump it is. I will reply when I get it replaced. maybe a week or so. don't get paid till then. Thanks again for all the help.

 

[TokyoSkies]

So water pump it is. I will reply when I get it replaced. maybe a week or so. don't get paid till then. Thanks again for all the help.

If that doesn't solve the issue, the only other thing I would suggest is a new radiator. Maybe there's a pinch or something in the core.

 

[civic2000sivtec]

alright, thanks again for the help guys