I have a Z24 Cavalier and theres white smoke coming out the exhaust and timing chain makes a lil rattle noise when I first start it in the morning and tends to stall until it reaches the temp of 165ish then it seems to run perfect and it also idles at 600 rpms when it should idle at a 1000 im thinking new water pump and timing chain should fix the problem it dnt leak oil and im not losing any antifreeze please help if you know any possiblities on wht the problen can be THANK YOU

SOURCE: 2000 maxima overheating

You have a new radiator and thermostat, so your coolant was flushed. Was the radiator "burped" afterward to get rid of air bubbles? If not, that needs to be done first - it would explain virtually every symptom you're seeing.

Jack up the car so that the radiator cap is elevated. With the coolant topped off, start the car and let it run until it's about 3/4 of the way to overheating. Then shut it down and go have a beer. When it cools off enough to safely open the radiator cap, do so, and any air trapped in the system will bleed out.

What you're doing is circulating the coolant and the air bubbles inside. The bubbles get lodged behind the thermostat and stay there, keeping it from opening (this causes the car to heat up). When you later pop the cap off the radiator, the pressure is vented from the system, the thermostat opens, and the bubbles pass through. They'll work their way to the radiator (since you've got it elevated) and pop out the open cap opening.

Your coolant level will likely drop somewhat after doing this, as the air bubbles will be gone and the space they took up in the system is now available. You may need to add a little more coolant, so top if off (with the car back on the ground) and recap the radiator, fill the overflow to the marked point on the tank, and you're good to go.

Try this if you haven't already, and post back up with your results. If it doesn't solve the problems, we'll take it further.

SOURCE: 1989 Cavalier Z24 3.1 rough idle and hesitation

I had the same problem with my Z when i had it. But it worked when i just left the little hose off of the EGR valve.

SOURCE: 98 Deville Northstar temp runs up to 240 when idle

Yes it is headgasket. Mine had same problem. Yours might not be severe as of now, you can try these other solutions. THERMAGASKET... Which you can buy online, and get your money back if it does not work... And stuff in a bottle at Autozone Repair headgasket with NanoTechnology! I would try and sell it quick, because these engines are very costly to repair and most mechanics wont even attempt headgasket repair, and plus you have to TimeSert the block...

SOURCE: rough idle on 1999 chevy cavalier z24

Check for vacuum leaks. Spray some carb cleaner or WD40 around the intake manifold, trottle body and any vacuum lines. Check for loose connections on engine wiring harness (Maybe you disconnected a sensor, and forgot to re-attach it?).

SOURCE: 1987 nissan pick up (z24 engine), while driving

blown head gasket between cylinder 2 and 3 ck compression