The sending unit that runs to the gauge in your dash is on the drivers side cylinder head, but that will not effect the actual temp. of the car. No sensor will determine the temp of the car, only other factors such as a stuck shut thermostat, fans not working, air dam removed, air in the system, etc...

I would replace the thermostat.

 

Heres something I found when My 95 Overheated on me. I had a 260 degree spike one night and after troubleshooting the thermostat, coolant fans/ switch and bled the air out of the system. After all that It still got hot. Problem solved by replacing the Radiator cap. The rubber seals were dry rotted and were not making contact with the radiator. you need a good seal on the radiator in order to keep the cooling system pressurized. Pressure helps keep the coolant at operating tempature. Any try that and see if it helps.

 

If that's truly the method you used there is still air in the system. Let the engine cool and refill it to the bottom of the filler neck. Start the engine and let it idle. When the radiator hose gets hot, open the bleed screws a few turns and keep them open until a steady stream of coolant comes out, You'll want to use rags to keep coolant off the Optispark. Anyway, when a steady stream of coolant comes out close the bleeder screws and fill the radiator to the bottom of the filler neck. REplace the cap and you should be fine.

 

I just wanted to add something that has worked well for me and it is jacking up the front of the car.
hope this helps
~greg

 

alright everyone. about an hour and a half ago i went to pick up the lady in the camaro. Well, after about 5 minutes the temp gauge was a little over a quarter the way up. i did about 80 on the highway for 5 minutes and my car pretty much stayed the same temp. As soon as i hit the exit ramp and slowed down to stop, the gauge shot up... I pulled into her work, opened the hood tried to bleed the system yet again, shut the hood, got in the car, leaned over and looked under the car and noticed there was a BBUUNNCCHH of water leaking from the LID of the coolant resovoiar. I filled it up with a bottle of water after it cooled back down. and i drove home. Again temp stayed about right even when i was only doing 35 40. I pulled in my driveway and yet again alllllllll the pouring water. BTW i JUST bought a RAD. cap off of summit for my Z yesterday. It got here today and said 16 P.S.I. I WAS PISSED!!!!! ALSO i know my cap is DEFFIDENTLY shot. It's all rusted on the inside except for the spring. I hope this info helps you guys help me. once again thanks for allll your guys' (and girls'??) help.

 

so the car heated up on my gauge all the way to the top. I opened my hood, looked at my radiator cap (measures temperature) and it said 240 degrees exactly. After 10 minutes it was half way up, i went through the McDonalds drive through for breakfast and i noticed it shot all the way up to 260-- the point of no return. I let the car sit for a half hour, got a mile up the road and let it sit AGAIN for 20 minutes. I really can't afford a 200 dollar water pump. But i'm out of guesses. I drained the system, refilled it, put a new R. cap on checked radiator for leaves/ any blockages. Only thing left is to buy a water pump. If the head gasket warped it's going to the scrap yard. I'm an 18 year old college student who works at meijer for 100 bucks a week with a baby in 6 months. BUT if i TRULY need a water pump i NEED to be sure that's the problem because after that my account is SPENT. I have a 16 P.S.I. radiator cap that Summit sent me ($31.96!!). The standard is 18 P.S.I.,(that's SUMMIT RACINGS fault) but i don't see any difference. My coolant light is on all the time now. (Little down arrow pointing to coolant). Every time i put water into the coolant reservoir the **** drains out after the car gets a little hit. maybe a blockage in there somewhere??? Any other guesses would be appreciated guys. Thanks much in advance. i REALLY need to get this figured out, because without this car my fiance and i have nothing to get to work in or to school.

 

If you want to see if your water pump is working pull the radiator cap off,start the car up and see if the water is circulating.One thing,did you put the coupling that connects the water pump to the water pump shaft back on? Part 39. Image below courtesy of shoebox. Also hows you oil press.?When my z overheated this fast it was due to spun main bearings,lets hope this isnt the case.




http://shbox.com/ci/water_pump.jpg

 

alright, well as far as part "39" goes. My dad put the whole water pump back on after he replaced the distributor(the biggest pain in the *** EVER!!!). So i can't really tell you if he put it back on. But i can tell you there were no parts left over. BUT i CAN take off the water pump probably in under 5 minutes to happily check for you. I did the radiator thing. I turned the car on for about 5 minutes, radiator filled alllllll the way to the top and started to overflow..... NO circulation i guess that means??? thanks. Ill wait for your reply until i take off water pump and check for water pump drive shaft(#39)

 

You shouldn't have to pull the pump to see if that part is installed. Pull off the intake elbow and you can see the waterpump..shine a flashlight in there and you should be able to see the area in question. There is a splined shaft on the back of the pump and a splined shaft sticking out of the timing cover. The part is a coupler that connects them....

If the coupler is there it's likely the water pump is bad. But there is one more thing you can try...take off the thermostat neck and remove the thermostat. Using tin snips, cut out the middle part, leaving essentially a big washer. Reinstall this 'washer' and check for flow. No flow this time means the pump is shot for sure....

If the coupler isn't there then that's the problem and you don't have to cut up the thermostat to prove it....

BTW, if you can remove the water pump in 5 minute you're a better man than I am!

Good luck to you...

 

ive been messing with this coolant system for a week. i've done everything other than take off the water pump lol. so this wont phase me. well i'm going to go check that coupler i'll message back what i find. I think it's going to come down to a new water pump because there is NO circulation whatsoever. Thanks for all the help

 

I would just jack the front of the car up on car ramps so you can pull the fans out.You can sit under the car and Pull the six bolts holding the water pump.Remove water pump,If the couplers there replace the water pump and gaskets,if its not thats the problem.Hope this helps.

 

well, i pulled the water pump. I have a refurbished one i bought from O'Reillys (murrays). I will install tomorrow. it was 79.00 hopefully it works or im **** outta luck. thanks for all the help appreciate it.

 

I didn't read anything about replacing the thermostat. Did you put a new thermostat on or not?

 

remember refill it with the front jacked or ramps. this will help the air escape since air rises.

 

Sounds like you're chasing deamons or you're missing something.

1) you don't have to drain and refill the system everytime; you're just introducing more air into the system everytime you do this.

2) When you replace the waterpump, also replace your thermostat; it's like $12.

3) Refill the coolent system and leave the cap off; start the car. Let it run for a WHILE!!! then keep letting the air out of the bleeders. Also, turn your heater on to make sure water is circulating in there and no air bubbles are trapped in there.

4) After the car warms up and no more air comes out; then put the cap on and continue to let it idle in your driveway. Watch for your fans to cycle on and off. You don't need to drive it or even move it to do this.

Then report back what happens when you do exactly this. No going for a blast around the block to warm it up; just take your time and do above.