Help! 1996 corvette overheating

[ztrouble8]

I have a 96 coupe with LT4/ 6 speed and it overheats when idling. I checked both relays and both fans run. I replaced the water pump and pulled the radiator, cleaning out loads of debris including blowing out the fins on the radiator and the condenser. Airflow is not an issue. Ran the car in my driveway for over a half hour with the AC on and it easily maintained the temp. The problem comes in when I turn the AC off. Is it possible that the low speed fan has no oomph anymore and is turning without moving much air? It climbs to 230 in a few minutes and drops if I get the car moving.

 

[LLC5]

I have a 96 coupe with LT4/ 6 speed and it overheats when idling. I checked both relays and both fans run. I replaced the water pump and pulled the radiator, cleaning out loads of debris including blowing out the fins on the radiator and the condenser. Airflow is not an issue. Ran the car in my driveway for over a half hour with the AC on and it easily maintained the temp. The problem comes in when I turn the AC off. Is it possible that the low speed fan has no oomph anymore and is turning without moving much air? It climbs to 230 in a few minutes and drops if I get the car moving.

230*F isn’t terrible at idle in hot weather. Most fans turn on about 225-230*F. My C5 fans turn on at exactly 228*F at idle.

 

[ztrouble8]

Wow!

230*F isn’t terrible at idle in hot weather. Most fans turn on about 225-230*F. My C5 fans turn on at exactly 228*F at idle.

That's uncomfortably high! It stays under 200 when the AC is on. I appreciate your input. Maybe I'll get brave and see if it keeps it from getting any higher than that.

 

[LLC5]

That's uncomfortably high! It stays under 200 when the AC is on. I appreciate your input. Maybe I'll get brave and see if it keeps it from getting any higher than that.

You don't want modern (basically OBD2) engines to run too cold or reliability, efficiency, and power will all be compromised, the 180*F days are over and done.

200-235*F is what they are designed to be run at, over 240*F is too high.

 

[Robertwav1]

My 93 aux fan turns on at 228°. It has always been this way. This happens only in a traffic situation.

 

[Scottsredvette]

Same as above, my 89 C4 normally ran 230-235 in heavy traffic.

 

[Otter]

Same as above, my 89 C4 normally ran 230-235 in heavy traffic.

Yep, the 89 I had previously did the same.

 

[Tuna]

Appears to be normal.
My old '96 LT4 would warm up to around 230 idling and at parade speeds with the AC off. AC on turns on the fans and cools it down.
The 'reverse flow' LT1 and LT4 engines were known for this behavior. My old '92 did the same.

 

[Wayback]

On at 228,kicks off at 217 on my 93. I friggen almost had a heart attack when my 1st C4 the 85 ran high,then found out it was normal.

 

[gmhowe]

My 85 does the same thing here especially in the summer. But its Phoenix so its expected