'92 240SX KA24DE problems: Waay too hot!?

[S14Dorikin]

Background on the problem:Ok, I bought a '92 coupe to become my next project car. Before I can do any swap of any kind I planned on running it with the stock KA as a reliable daily driver. When I bought the car the seller made me aware that the idle was high and he thought it might be a vacuum leak, easy enough right? So I bought it but could never find the vacuum leak. After a week I got really annoyed and had to find it! Idle being around 1500-2000 and sometimes fluctuating up and down and sometimes, but rarely, sitting right at 1000.

A few friends and myself also tried dumping some seafoam into the engine to sea if any leaks would show itself, nothing. However, when we unplugged the vacuum line from the brake booster to put in the seafoam we found that instead of the car sputtering and having to blip the throttle to keep it going while sucking the seafoam, like most cars do, the engine actually stayed fine and the idle calmed down to normal without manipulating the throttle at all....hmmmm.So we figure instead of a vacuum leak, its getting too much vacuum in the crankcase. We take off the oil cap while the engine is running and it starts blowing out A LOT of air through the hole. My valve cover gasket also looks like its seeping a little. My first thought is the PCV is bad and its not relieving the air from the crankcase. So I buy a new one, and off we went through the whole KA24DE PCV replacement mission, how fun. I went the under the car route by removing the alternator and draining the radiator.

Heres where my problem lies:After I replaced everything I find that Alternator belt is squeeling like hell until I rev it and my idle has not changed from before and is still effed up. NOT only that BUT, my temperature is rising like crazy, all the way to Hot in around 4 minutes of sitting at idle.I let it cool down over night and waited for my friends to come over. We opened the radiator cap and topped it off a little because I opened it the night before and it spewed everywhere.I start the engine with the cap off so my friend can "burp" it and monitor the coolant in the radiator. All of a sudden he yells "shut it off!" I look over and he says "it just spit all the coolant out the radiator cap!" After this we're thinking maybe the thermostat went bad and is stuck closed and isn't letting any of the coolant into the engine so it winds up ejecting out of the radiator and the engine gets hot since theres no coolant coming in.

Tomorrow I want to buy a new thermostat and maybe a new coolant temp sensor to see if that helps the idle and overheating. I might also try cleaning the throttle body and IACV. I just wanted to get opinions from others. I'm not too experienced in this, my friend is almost finished with his Automotive tech degree, but I'd really appreciate any help from anyone.Like I said, this is my daily driver for a while and I just want to get this engine running smooth. Thanks in advance.

[Florida240sx]

CTS could be the cause for idle problems.I don't run a thermostat in either my vert nor my ka-t hatch.I've had 0 problems bleeding the cooling system. Even did with a thermostat on a friends cars.Get one of the radiator fill funnels so you cna actually have more water than needed above radiator Fill up to top and start squeezing top radiator hose.Once bubbles stop crank the motor and continue squeezing. Do this about 3times. Then start the engine and kill immediately. Squeeze hose again.. Repeat step again. Now start engine while squeezing hose run for about 15secodns and kill the engine. You should be good to go as far as air trapped in the system.

[Florida240sx]

You've run a tank of gas through it yet? Possible low octane?? Checked fuel filter?

[S14Dorikin]

CTS could be the cause for idle problems.I don't run a thermostat in either my vert nor my ka-t hatch.I've had 0 problems bleeding the cooling system. Even did with a thermostat on a friends cars.Get one of the radiator fill funnels so you cna actually have more water than needed above radiator Fill up to top and start squeezing top radiator hose.Once bubbles stop crank the motor and continue squeezing. Do this about 3times. Then start the engine and kill immediately. Squeeze hose again.. Repeat step again. Now start engine while squeezing hose run for about 15secodns and kill the engine. You should be good to go as far as air trapped in the system.

I'll try all of that before I do a thermostat. But not sure if I'll be able to burp it without it gushing out at me like before.

You've run a tank of gas through it yet? Possible low octane?? Checked fuel filter?

Ran about half a tank, I'll check it though.

[S14Dorikin]

Ok, replaced the Coolant temp sensor but Idle is still high at start up. Once it hits the point where its at running temperature the idle bounces up and down between 1600-2400. After bouncing for about 5 minutes the temperature goes all the way to hot.

I havn't changed the thermostat but it seems like coolant is circulating so I'm not sure if thats the problem. Anyone have any other ideas?