I live in Phoenix where it will be 100 degrees this week my 96 is running at 220 degrees. Is this about right? and if it is what temp should I start to get worried. The fluid level is O/K

 

Normal operating temps:
Sitting still with engine running: 215°F - 235°F
Moving at any speed above 35mph: 190°F - 200°F

Note:
All temp readings listed are based on the digital temp gauge.
When the digital temp gauge is reading 228°F, the analog gauge will look like it is almost pegged. But look close, and you'll see the needle just short of the shaded area.

Some people don't like seeing those temps, but they will not harm anything.
A cooling system in good condition with the proper coolant mix and pressure cap, will not reach the boiling point until close to 260°F

 

If you aren't comfortable, pull the radiator and have it boiled out at a radiator shop......scale build up inside kills heat transfer.

Only use distilled water from here on out........

 

I've seen my early C4 run close to 240* in stop-and-go traffic during the summer (of course, WI is nothing like AZ). While it initially worried me, the car doesn't seem to mind it.

 

X2

I would get concerned at >240

 

I have a 1990 and I just changed my original thermostat from a 195 to a 180 and it runs the same in traffic as it did before. The temp runs close to 120 then the fans kick in and it cools down. My problem was a lack of heat.

 

selecting air conditioner will activate the fans and run cooler if the air is not being used.

 

Not likely that your radiator needs boiling out, BUT...my money is on it really needing the cooling fins cleaned out, particularly at the bottom of the radiator. C4's use air from the bottom of the car and all kinds of small debris gets into the radiator and A/C condenser fins and it pays to clean them out.
Normal temps over 35 should be about the opening temp of the thermostat, a few degrees higher in the summer. While sitting at a light the main fan will come on at 228F and the second fan at 238 F. GM says to shut the engine off at 260 F and let it cool down. I doubt very much that you will ever see 260. GM says this because 50% coolant at 15 psi boils at 265 F and most of the heat is in the heads and boiling coolant cannot remove much heat and you could damage valves or the heads. If no boiling would occur, even 265 F is a nothing for an automobile engine. A lower opening temp themostat will do absolutely nothing to your coolant temp except in cold winter temps. Thermostats set the minimum temp an engine will run at, but once the thermostat is fully open it has no effect on the coolant temp. The coolant temp then settles where the radiator gets rid of heat as fast as the engine makes it.

 

Have a similar problem on my '95. Have seen the temp gauge showing 260 frequently while stuck in traffic. But shortly after hitting that peak, it drops rapidly back to about 210, which seems to be where it normally sits. Changed thermostat/radiator cap to catch anything obvious, but assume the problem is in the fan operation (and assume the fan(s) kicking in is the reason for the rapid drop in temp). Only had car for six months (180k miles) but thought one of the things replaced by last owner was the radiator. Last month, I ran over a 'gator' (semi trailer tred) that took out the air dam underneath and beat up some of the underside. Had that repaired but after reading post, wonder if damage could have occurred to the radiator or could debris have damaged the lower radiator fins. Looking for the next logical place to turn my attention too. Suggestions??
PS - this is my third Vette, but after working on the plumbing for this one, am still not sure how to check the correct water level. How do I tell when I've got the right level?

 

I've seen this said in the past and I just did it so I'll have to agree: Remove the shroud and clean out the cavity between the condenser coil and the radiator. I really can't believe what I found in there and you wouldn't think it because everything was clean. When I removed my rad I had squirrel nests in there and at least 4 rows were clogged with muddy, rotting leaves. I removed the radiator + vacummed out the crap + a tranny cooler + pressure washing everything = HAPPY CAR Then I added a screen to keep this crap from happening again. Check "My Garage" pics and look at the screen I added to my front air-dam, I picked up the galvanized screen at Home-Depot .

 

caddyboy84 - Thanks for the info. Will check to see if I have debris, and have contacted my body shop to schedule a re-examine to see if the radiator fins got damaged.

 

The radiator is protected by the condenser coil, so if anything, the condenser coil got damaged. If the damage isn't bad you can "comb-out" the damage with a coil comb. I bought my comb set from a catalog at work, so I don't know if a local store would have them but it's a MUST HAVE for any tool box. Do a Google search for condenser coil comb set and see if you can find it, maybe E-bay has a set.

 

The OP is in Phoenix, and Arizona water can be hard as a rock.

But I'd check for debris first.


Chuck

 

If it really bothers you to have your car run this hot, there's a solution, do what I did...Plus your car will be faster, because your wallet will be much lighter...........WW

Install Dewitt's aluminum radiator
Install Dewitt's high speed fan
Install 180 degree thermostat
Have fans set to come on at 195-200 degrees.......Problem solved...WW

 

LTX engines have a 180 degree thermostat from the factory.

 

Good Tip about cleaning out the bottom of radiator. I'm still new to the C4 and just went outside and found leaves and sticks jammed up there. Thanks.

 

Clean out the A/C condenser / radiator cavity FIRST. see attached

 

A word of warning to the OP.

Your '96 radiator is not as easy to access as the instructions in the previous post.

There are six (6) fasteners for the upper shroud that are a PITA to remove. Three (3) on each side of the shroud.

What I have done is reverse where the fastener is attached after removing the upper shroud. This makes the screws accessible from the bottom front of the vehicle. Corvette has the fasteners attached where you need to remove the screws from either side of the shroud in the engine compartment. Probably easy to do during assembly before the hood is installed.

You will be amazed at what type of debris you will find.

 

Just did a customer C4. You would not believe the junk in the rad and condenser! Also, I put in a can of rad flush, and flushed the whole motor out about 4 times. Then I realized the brand new thermostat was stuck closed. I put in a new one and also drilled a hole in it to allow air to bypass. Then the damn brand new fan switch on the passenger side went south, so I put in a programmable, and Bob is your uncle. It ruined the looks of the engine bay, but at least the car works now, and this is a one-fan 1984 model. Patience, patience.

 

It's been 6 1/2 years so he's probably fixed the problem by now...WW