I know there was a thread on this not too long ago, but no one seemed to get their temps. much over 220. Mine reached 240 today in normal city traffic. I just got this car in from Arizona and have not flushed the radiator yet. Is this a dangerous temp. and if it is, what measures should I take to remedy. This is an 89 model coupe, all stock. Thanks

 

I think 240 would tend to bother me a little bit. Sitting in traffic in very hot weather, I will see temps hit the low 230's with mine. My fan kicks in right around 230, so it never goes much over that before cooling itself down... Although I think the fan kicks off again around 220 or so and then the process begins anew.

Running down the freeway in high heat conditions, I usually see temps around 205-215. When the sun goes down, if it's a nice night, I feel much more comfortable with 193-198 highway and no more than 205 city driving...


Since the car is new to you, I would definately flush the radiator. Also remove the shroud and clean out in front of it... there could be leaves and whatnot stuck in there causing you to heat up.

My car also came from AZ. One thing I found in the winter months was that I could never get any heat... I assumed the thermostat was stuck open. Imagine my surprise when I pulled the thermostat housing to find.......... nothing! Thats right, no thermostat. The previous owner had just removed it completely... Nice. After replacing it, I also found that my heater control valve was clogged - keeping me from reaching operating temperature.

I put the factory 195 degree stat back in and changed the control valve. The temperatures I described above are what I get now with everything functioning as it should...

 

I'm going to flush the radiator and change the oil soon. I checked for trash next to the radiator and that wasn't a problem. Once I do the flush, I guess I'll go from there. THanks

 

I just took a class from one of the Corvette gurus named Chris Petris. He says that the very hottest you should ever get with a C4 is 230. Here is a pic of the area BETWEEN the radiator and AC condenser. You cannot see what is there unless you pull the radiator shroud off first. I think you can see there on an LT1 but not on the 84-90. This is mine with 3" of leaves and crud.


Here is the" after the shop vac" pic

I drove the car on a trip to the Chicago area after I did this clean out and even though it was at a dead stop with the AC on in 94 degree outside temps for 45 minutes on I-94/80 the highest it got to was 213.
You can search the Forum for a how-to for this operation. I would also suggest that you replace your radiator cap with a new GM part along with a full flush of the radiator and heater core and new radiator hoses too. Both Richard Newton and Gordon Killebrew (2 other Corvette Gurus) have stated that overheating and burst hoses are the #1 reason you find a C4 dead on the highway.

 

Great info. there. Thanks. By the way, I can get plenty of heat to my car. I just turn on my air conditioning!

 

Sounds like you have a couple of things to fix

 

Another thing to look at is the front spoiler. It's not unusual to see the spoiler broken out on older C4's and it is an important component in keeping these cars cool. They force air up into the radiator as the car is moving and go a long way to keeping the temps down. If the spolier is broken out in the middle or missing there will be significantly higher temps.

 

How do you guys get these exact temperatures? Have you installed different guages? My stock guage goes from like 100 to 260 so all I can do is ballpark the temp.

 

I replaced the radiator on my 88, and found the above mentioned leaves and also plastic shopping bags melted to the coils!!

 

We have very good eyesight.

Actually, the cars with the star wars dash (84-89) had digital readouts for coolant temp. In 1990 Corvettes went to analog gauges but in 1992 or 93 digital readouts for coolant temp, oil temp and volts were added to the gauge package as well. I don't think 1990 or 91 had the digitals available.

 

Since I drive almost daily in stop and go traffic, I put a switch in my car and hot wired the fan. That way it will just run the whole time I'm in traffic. My car hasn't gone over 214 - oil and 212 - radiator yet this summer.

 

You can get a digital readout, in celsius, by doing a couple of button presses on the climate control unit. The combination and number you select afterwards eludes me ATM, but I know I read it here on the forum.

 

OK guys, I just flushed the radiator and renewed the anti and everything is fine. The fan is kicking on when it reaches 229 just like my owner's manual says and immediately brings it down to around 200 at idle in town. I think, at this pt. it's working, at least, as it was designed to. Thanks for all the help.

 

Mine routinely runs in the upper 220s to mid 230s during the summer in traffic. If I have the roof off I just turn on the AC on and the temp comes down. Fans don't normally come on until 230+. Haven't had any problems.

 

Mine seems to be set to come on at 229. Now that the coolant has been changed it seems to be working perfectly. Thanks

 

don't forget to purge the air out of the system. That is VERY important.

 

there are more people on this fourm trying anything to see how low they can get their temperature....

next thing someone will create some dry ice pump... i can see it now... "i sit in traffic in arizona in 119 degree weather with heavy traffic and the air conditionin on and my temp is below 100!!!!!"

it cracks me up...

 

i got bored one day and yank my radiator. after removing all the leaves, cig butts and a beer bottle cap and a plastic bread wrapper i held it up and tried to look at the sun....dayum...that thing was plugged up real bad, mostly the center section. took me hours to get it cleaned out.
mine is all stock and it never goes above 210-212.