I was out for a cruise yesterday and got stuck in light traffic. The car started to overheat. It got up to 240, as soon as I started to move it cooled right down. It was only about 65 degrees yesterday, so i know why it cooled down. I'm pretty sure the fan isn't kicking on. Any ideas would be helpful.

 

Rob,refer to my post on your doorlock post. An inop fan can be the switch in the engine,the fan motor itself,the relay that controls the fan,or any wire or connection in between. Possibly in the later models it could also go thru the ECM. All my books are for an '84 and there will be some differences in the later models. again,Good Luck!
Ron

 

Don't know what year you have, but am assuming that you are referring to the temp reading from the analog gauge in the speedo. The later cars have the capability of reading the temp digitally, which is more accurate. (what year do you have)?

If this happens again turn the a/c on & see if it cools down fairly quickly. The fans come on at 226# & 236# under normal conditions.

These engines run warmer than most.

 

You could also check in front of the radiator. A conglomeration of junk (leaves, dirt, deceased bugs) collecty there and clog the radiator. It can be viewed, accessed and cleaned out via a hole on the passenger side in front of the radiator. It may not be the problem but a good cleaning can't hurt.

 

Sorry guys telling you what year it is would probably be helpful. Its a 91 with 96k on it. It got up to 240 or so and the check gauges light came on, just as I started to move. I'm not sure if the fan did kick on or if it was just the cool air cooling it down. This is my first vette and I'm trying to learn all I can about it. I appreciate all the help. And I'm sure I'll have plenty of questions.

 

240 is too high for 65 outside, especially when the summer hasn't heated up pavement/asphalt/road surfaces yet.

Put the heat on max, and grab hold of the heater core lines. If they're close to the same temp, you have little flow through the core (and maybe elsewhere too). If they're different temps, there's good flow through the core, and it's takin' some heat from the system in the form of cabin heat.

 

I just had the radator cleaned on one of my 95's and the shop said it was plugged up inside and outside.
Runs cool like new now.
He also said I had a leaky expansion tank [ I replaced it ] and a bad cap !
Your cooling system has to be up to snuff on these cars.
You can check your fans by putting A/C switch on and observing your fans both turning.