OK, I searched posts for hours so I am just going to throw this out there
My car, as pictured, runs on road for about 5 minutes on the road and the gage heads straight for 200'. Turning the defrost on brings it down a touch, but not much. I am a C3 head so this pressurized system is a new animal to me. I've told thermostat bad and all the horror stories. No leaks, no visible overheating, just runs hot--and it feels hot when I open hood too. Best I can tell the motor is stock, has 71k on it. And runs fine--just hot.
any suggestions would be appreciated.

 

It probably has a 190 thermostat in it. The new cars are designed to run between 200-220, the fans don't even kick on until nearly 230. The reason turning on the defrost brings down the temperature is that the defrost turns on the ac, and the ac turns on the fans. Monitor your guages, but don't worry, it sounds normal.

 

Don't worry, its all good. My '94 runs anywhere between 198-230(in traffic). Its normal for the c4's. My dads L98 runs about the same.

 

The fan isn't programmed to come on until 228 Sounds crazy but it's fine the way it is.

 

Your car is the first year of the programable learn computers.
If you don't like your settings you can buy a hyper tech programmer and reset the computer in the car yourself.
They run about 200.00 bucks or less.
I reset my computer,fans to come on at a lower temp but remember the fan will run more and may cause premature failure.
I installed a 160 stat and the car runs around 180 to 205 in traffic.
Your year car you can change all kind of things but read up on it first.

 

Nothing came up in a search on this subject huh?

To be serious, 200 is perfectly normal.

 

I'm pretty sure the 94s had 180 thermostats in them; mine does anyway. Make sure your radiator is clean. I have had the fans reprogrammed to come on at about 215 and 220. In normal weather (not super hot) I run about 190-205 degrees. In this current super hot 100 plus heat we are having in the west, I run about 205-212. I also have an electric water pump which helps even out the temps in city driving.

 

without resetting the fans, anybody else put in a 160' thermostat? I thinik that is the minmum you should put in this model.

 

Gets kinda cold in Amarillo, I think I'd go with the 180. All the thermostat will do is allow flow sooner, it won't really affect your normal running temperature (unless it's really cold!)

 

I ran the 160 thermo in my 96 for @ 9 or so months while waiting to get a tune. IMHO, it was useless before changing the fan settings. My temps didn't change, in fact I think my temps may have been higher expecially in town sitting in traffic (or I may just have been more conscience of them). Now w/ the fan settings changed--she runs 180 - 185 max in town and 175 on the highway. Again, JMHO...

 

Amarillo, cold? for about 45 days in winter and then its hot dry high desert
the term dustbowl comes to mind.

 

what effect does air in the system have? who makes this hyper tuner programmer? any info?

 

The short of it is that air in the system means that the cooling system will not cool as well. The long of it is that air is a poor conductor of heat. Air in the system can lead to cavitations at the WP impeller. Air can compress while water is almost incompressible. Air in the system allows the coolant to boil at a much lower temperature than if the system is well purged. The cap acts like the weight on a pressure cooker and regulates the pressure in the system. A system like the ones in C4's can keep the water from boiling up to about 260 degrees F at which point the general says we should turn off the car, wait for it to cool down and contemplate whirled peas.

 

That is why the system is under pressure. That 15psi increases the boiling point of the coolant to approx. 260 degrees F (at sea level).

The bottom line is, temps in the 200 - 220 range are perfectly normal for a C4 and will cause absolutely no harm.

 

I have an 87 C4 that always had an overheating problem I have the stalker fron end and live in southern Idaho it gets hot here in the summer. with the A/C on in traffic it would hit 240 250 and one time 273 ( on the old engine ) with no control so I would have to turn the A/C off an bake. I tried the water wetter stuff distilled water and what ever other crap they said would help but nothing. had a custom built 5 row staggered core radiator built didn't help a thing except for making my wallet $875 lighter put a Balck Magic pusher fan on it then replaced the stock fan with a Black Magic puller worthless. Built a custom sealed air dam in front of the radiator completely sealed. Sealed the radiator to the a/c condensor a/c condensor to the core support sealed the core support to the air dam and nothing still couldn't run the a/c if it was over 85 degrees outside. took the rubber seal out of the hood by the windshield to let air pass over the top of the motor nothing worked. I know there's more that I have done but I can't remember I had it to every radiator shop in town and they all said that they couldn't think of anything more to do except move to Alaska. Finally I went to the junk yard and bought a stock fan out of a 93 for taurus made an aluminum shroud mounted the fan Installed a 160 amp alternator because this fan pulls 70 amps on startup and a Moroso filler neck that I put in the top radiator hose as close to the stat as I could at the highest point so I could get all the air out of the motor and radiator and finally it worked. this is a 2 speed fan I have only run it on high a couple times. you know when you walk up to a fan that blowing hard and it takes your breath away this fan does that in low speed. in low speed with a 160 stat 95 -100 degrees outside in traffic with a/c on this thing would run 155-160 so I put a 205 stat in it now it runs 200-203. I spent about $2000 and hundreds of hours poking and hoping. the final solution cost me $35 for the fan ( Junk yard ) I think $160 for the alternator (Jegs) because the fan would pull my battery below 12 volts when it was running with the stock alternator and about another $100 in wire and a 70 amp solid state relay from my local control house and took about 30 hours to get it all done oh and about 20 hours of **** from friends for putting a ford part in a chevy. there are alot of sites on the internet that show you how to wire these fans and it's not tough at all if you need them let me know and I will send you the links

 

THE C4 AND C5 NEEDED TO HAVE MORE AIR FLOW TO THE RADIATOR ESPECIALLY IF YOU HAVE MODIFIED THE ENGINE A BIT. WE HAVE THE PERFECT SOLUTION FOR YOU ITS CALLED THE BIG MOUTH PERFORMANCE AIR DAM AND HERE IS A LINK FOR YOU LOOK AT WHAT THE FORUM GUYS SAID , PLUS IT LOOKS VERY COOL AS WELL !

http://forums.corvetteforum.com/show...light=bigmouth

 

Thanks but if you look at the front of my car, I have a bigger mouth--all of the air from the front is pushed straight at my radiator. thanks for the thought.


[QUOTE=golfman2008;1561261905]THE C4 AND C5 NEEDED TO HAVE MORE AIR FLOW TO THE RADIATOR ESPECIALLY IF YOU HAVE MODIFIED THE ENGINE A BIT. WE HAVE THE PERFECT SOLUTION FOR YOU ITS CALLED THE BIG MOUTH PERFORMANCE AIR DAM AND HERE IS A LINK FOR YOU LOOK AT WHAT THE FORUM GUYS SAID , PLUS IT LOOKS VERY COOL AS WELL !

 

took out the car today. its 90 degrees. After a 15 minute 70+mph run down the I-40 to New Mexico, then 15 back, I sat at the offramp light and it climbed to @220 degrees or so. this car is so different from my C3's in this respect. Did the same thing with my 82 collector that has a 160 thermostat and it was resting about 190. I know the C3 gets more air, much more from the bottom of the car than this C4.

there is a mod to turn the front plate sill into an ram air vent for the intake, has anybody ever seen this turned into a ram air grill for radiator? I am concerned about the turbulence it may or may not cause under the hood.

Any body seen the air damn I have modified with vents(like brake ducts) that would aim to radiator--got to be some racers out here that have a clue what I mean.

time for some aero mods.

 

Have you crawled under it and pulled the leaves and pine straw out of the radiator? Also, from the top if you remove the shroud you can get the rest of it. These cars are like vacuum cleaners for road debris.

ref: http://forums.corvetteforum.com/show....php?t=1730275

 

Yes, it is different than a C3. The C3 had a mechanical fan. The C4 has electric cooling fans. The electric fans will not even come on until close to 228 degrees F.

Sitting at a stoplight, it's perfectly normal for you car to get to 220. The cooling fans are not running yet. Turn on the A/c, and they should come on.

If your car will not stay below 230 degrees, then you have some issues to deal with. As was mentioned, look for debris clogging the radiator fins. When the fans come on, these cars will "suck" up all kinds of stuff.