I was driving about 80mph but had to slow down to about 65 due to traffic, when I noticed my "check guages" light was on and my coolant temp was up in the red. I turned the heater on full and pulled off the highway. There were no signs of coolant leaks and the radiator fans were not on.
I have several questions.
1) Does the coolant temp guage measure temp from the same source as the temp sendor that turns on the radiator fans?
2) Does this sound like a stuck thermostat?
3) If the radiator is full when I check it, what else should I check?
Thanks for your help,

 

The fans should have came on at that temp. For your 1st ? is no, first is check the level, and then check to make sure the air dam is still in place, and make sure there is nothin blocking the condensor.

 

well the temp ur are looking at on ur dash (if i remember correctly) is a sesnor on ur cylinder head...

so i would check ur thermostat, toss it into a sause pan w/ water.

but sounds like ur fans arent working, those things are loud and when the second one comes on its extremely good at cooling ur system off, after a minute of my second fan coming on (usually if im on surface streets my temp will creep up on me, and usually i'll notice but sometimes it will get to 230 before i notice) so it'll take about 1 minute to get to 195 from 230, so it works quite well...

 

Update,
The air dam is still in place.
There is nothing blocking the air flow to the radiator.
The coolant was about 16oz low in the radiator and was a little below the fill cold line in the coolant reservoir.
I filled the radiator and the reservoir.

Do you think the low coolant would have caused my problem?
I still don't see any signs of leaks including anything out of the exhaust... Where did the coolant go???

 

1) Learn to f'ing spell....You're not text messaging your dimwit friends...It's a forum and if you want to help people who have a problem, at leasts APPEAR to have some coherency...and intellect.

2) Sounds like your fans aren't working..? How the hell is he supposed to 'hear' them at 80mph?; Aside from that, the airflow at highway speeds blows away idling @ a dead stop.....irrelevant.

3) The first fan kick on at 226+ degrees by design, but running the A/C will kick them on regardless of temperature shown.

4) If you're in doubt of your facts, direct him to ever-reliable, doubt-proof Shoebox.

Rue the day your mess of a resume crosses my desk...

/rant off...

I'm just tired of the clueless Z-owners that can't be bothered to pick up a book, read their manual from cover-to-cover, or present a concise, well-written answer ...

 

Holy ****!

 

Hey UNIQUE..... just from your name... maybe you figure you are, but dang dude, take a chill pill. We all know newb is just trying to help and giving him options. If your talking about his "ur", I don't see any biggie with that. If you don't like his answer just correct him, no need to bust on him, his friends or his intellect.

 

Mark, best laugh I have had tonight!

 

16 oz is quite a bit of coolant to be down on. I think your biggest problem is not so much why the car ran hot, but where all the coolant went. You probably need to check all your hoses and also see if the water pump is leaking or you might be replacing an Opti pretty soon. I know that in the past when a thermostat went bad, it would stick until the pressure built (causing the temps to go up), then it would be forced open and the temps would go down again.

Try letting the car idle in your driveway for 10-20 minutes (with you watching it) and see if your temp gets above normal. You should hear your fans kick on. Then check for drips under the car.

Hey Unique, much like the rest of us you aren't perfect either.

Might want to check your resume while your at it.

 

heh ive had my fair share of coolant problems, but this one is truly Unique...

Im sorry that my writing is flawed and that you have taken insult by my lack of intrest in the art formerly known as grammar. I didnt realize posting on here was such i would begin each artical with my sir name. If its expected to respond with the answer only shoebox would know, I would find help elsewhere because often times his replys come slowly but surely while i want an immidiate answer. This paragraph has fragments and run on scentences but please excuse my inabilty to exersize my freedom of speech with perfect grammar.
This is truly my fault. I appreciate your venting on me...

Please forgive me,
-Newb

 

For what it is worth, I appreciate all the help I can get. So, thank you.

I let the car idle for about 20 minutes this morning and it quickly warmed up to a little over 200* and stayed there... I'll re-check all of the hoses and around the water pump for signs of leaks.
What other things might cause loss of coolant? Would a bad radiator cap cause something like this? I'm not sure why the fans did not turn on when the temp guage showed the system overheating... When I turn on the AC, the fans came on. That being said, I agree that at highway speed, there was plenty of air flow, so the fans should not have been necessary. Could air in the system cause a problem such as this?

Thanks again,
Steve

 

Check the rubber hose between the radiator fill neck and the reservoir for cracks. If that hose cracks, it allows air to be sucked into the radiator when the system cools down, rather than coolant from the reservoir. Also, now that you have refilled the system, check the air bleeder screws to make sure you have all the air out.

 

Haha, here you are telling him to show "coherency...and intellect" when it appears that you haven't mastered the use of the period at the end of a sentence. Also, I have placed in italics your 1st grammar error above, in this wonderfully composed rant of yours. It is *at least APPEAR to have* and not *at leasts APPEAR to have*. Thanks for playing.

Good point. However I don't agree that highway driving "blows away" airflow movement with the fans on at idle. My car used to run hotter on the interstate than it did in town. My theory is that the cooling fans are more efficient at moving air through the radiator because on the highway air has to be drawn up and then through the radiator. Like I said, just a theory.

Wow you must have a lot of time on your hands. You also must be real important if you actually have a desk, and someone trusts you to review resume's. The guy made three points, and two of them were right on target. Yes the sensor that reports to your gauge on the dash is in the cylinder head, and also testing the thermostat by putting it in some water and heating it up would be a good idea. I think he misread the part about slowing down, and thought that maybe he was stopped and heated up because the fans didn't come on. It's an honest mistake. Also, he or anyone else on here doesn't need a commentary from you about how clueless you think he is Why don't you go review some resumes.

Actually Mr. Unique07, I'm not done with you yet. You decided to waste some bandwidth on this thread, there were 3 questions asked by the original poster, you successfully answered..... hmmmm wait a minute.... <looks around> 0. ZERO!! You outlined four points, and then summarized it with a paragraph that sounded like an eight year old crying in the supermarket when his mommie won't buy him the fruit roll up he wants. You added absolutely nothing to helping this guy out here, just whined. Thanks for your input, now you can go review those resume's.

 

Ohhhh boy.........give me a tissue.

 

The fans don't normally run at highway speeds.