Running Hot

[Otis3]

I have a 93 coupe with an LT1, the cooling fans are not working. The
temp got up to 227 while stopped in traffic, but went back to 190 as
soon as I started moving again. When I got home, I let it idle untill the
temp got up to 210, and neither fans were running. I check both fuses
and are OK. I looked in the Mid America catalog and found a fan switch
for a 84 thru 89, but nothing to help me. Does a 93 LT1 even have a fan
switch ? And if so, where is it located ? I really don't think both fans,
and both relays would go bad at the same time. Is there any thing else
that I should look at besides the fan switch ?

 

[Ken]

Have you checked for any codes?

 

[c4cruiser]

Those temps are normal. The stock thermostat is a 195 degree so expect operating temps between 195-205 or so. The primary fan comes on around 215 and the secondary fan comes on at 228. The secondary fan can also be forced to come on simply by turning on the A/C.

There's no fan switch per se as the fan relays are controlled by the ECM. Temp input to the ECM is provided by the coolant temp sensor in the cylinder head. The ECM will turn the primary or secondary fans off when the coolant temp lowers. With the A/C off and cruising at highway speeds, the fans seldom run.

Airflow thru the radiator is very important in keeping a C4 running cool. Look up under and behind the front license plate and check for debris. Use a stream of water from a hose directed from the fan side of the radiator to clean out the junk.

 

[vetteboy86]

Use a Jumper wire to connect the fans up directly to a 12 volt source. You could track this thing down. I dont know about the dual fan set up, but the fans dont come on at the same time. However one should come on when you kick the AC on.


Good luck
Craig

 

[vee93]

I have a 93 coupe with an LT1, the cooling fans are not working. The
temp got up to 227 while stopped in traffic, but went back to 190 as
soon as I started moving again. When I got home, I let it idle untill the
temp got up to 210, and neither fans were running. I check both fuses
and are OK. I looked in the Mid America catalog and found a fan switch
for a 84 thru 89, but nothing to help me. Does a 93 LT1 even have a fan
switch ? And if so, where is it located ? I really don't think both fans,
and both relays would go bad at the same time. Is there any thing else
that I should look at besides the fan switch ?

Check---or get-- your head pressure checked. A few months ago, my '93 couldn't idle in traffic for more than 2 minutes without the temp topping out. I don't care what the engine was built to withstand, nothing can take that kinda heat over time. My Vette's head pressure was up around 300+. It's corrected now-somewhere in the 200s and the Vette now runs smooth and strong. I also know that also corrected a stumble upon acceleration it was having in the low RPMs--especially when it would run that hot. Just a thought.