noticed the primary (?) drivers side fan comes on at about the 3/4 way mark on the guage Im assuming this is 238. When is the second one supposed to come on. If I sit in traffic long enough it damn near pegs the gauge. Once Im moving it runs a little below halfway and maintains it Ok most the time.

Is there a way to make these come on earlier, its driving me friggin nuts. Radiator is near new and so is water pump.

Is the 2nd relay the one towards the front or the one behind it?

I know these are supposed to run warm but this is stupid.

 

Was it burped properly?

 

I have no idea, only had it two days.


2nd fan does not come on when AC is turned on.

Is there a fan switch in the head that is lower temp I can put in it?
Wheres the 2nd one located?

 

GM changed some things with the introduction of the LT1 (e.g. the coolant flow is reversed through the engine -- cooled coolant enters the engine via the thermostat).

The Engine Coolant Temperature (ECT) sensor (which is screwed into the front of water pump) directly feeds the PCM, which in turn feeds information to the Digital Dash (via the CCM I believe).

So, using the 'gauge' button on the DIC (driver information center), cycle through the different digital dash readings and examine/advise the digital dash's 'coolant temp'.

By contrast (and I presume the gauge you been looking at) the analog temp gauge is fed by a seperate coolant temp sensor mounted in the passenger side engine head towards the rear of the engine.

Generarlly both coolant temp gauges should be about the same.

BTW, the fans are controlled by the PCM, so unless a 'bypass' ground temp sensor is installed, or the PCM is re-programmed, cannot just change a temp switch to cause the fans to come on differently.

Typical temps should be 195-200 F during normal driving (A/C on or off), up to 228 F at a light with A/C off before primary fan (driver side) comes on, or at 236 F the secondary fan (passenger side) will also come on assuming A/C is off. With A/C on, both fans should come on pretty much right away (assuming the A/C system is properly charged).

If they are not about equal, it could imply numerous issues, such as:

1. wrong thermostat (LT1's take a special thermostat with an extra plate on the bottom to close of the internal passage ways).
2. blockage in the heater hoses or heater core.
3. air trapped in the engine.
4. steam/air bleed-off lines clogged (at the back of each head routed to coolant pressure tank).
5. debris clogging the A/C condensor, preventing air from getting through to the radiator
6. radiator cap defective and not holding in pressure
7. head gasket failing
8. coolant old and no longer preventing spot-boiling

 

The relay closest to windshield is for the secondary. You can swap the connectors to verfy that your secondary is operating correctly.

On my '94, my secondary would not kick on when I turned on AC. I checked the AC charge, and it was low(compressor was cycling on/off way too much at idle). After I charged the AC system, the secondary now turns on when AC is turned on. There was a thread on this by another '94 owner about a week ago.....

What temp is displayed on your digital readout when the "analog" gauge is almost pegged in the Hot zone ?

 

I dont know, Ill have to check the "real" temp. Fan doesnt kick when AC is on, think I know what I have to do.
Thanks guys.

 

I posted about this last summer too -- here's the link:

http://forums.corvetteforum.com/c4-t...-on-by-ac.html

 

Sounds like your car was running as it should be, these motors are made to run hot....emissions emissions and emissions. My 93 LT1 (40mi) used to run the same...way too hot, found a mechanic who had gm programmes for these cars and can go into the computer and alter the temp.
My 1st fan now comes on at 203 second at 205, brings temp down to 193-195.
Absolutely perfect! best money I ever spent, unless your car has some other physical problem, this is a guaranteed fix

 

Checked today when the needle is just about half way its at 195
When its almost pegged its at 227-230 where the first fan comes on.
Funny if it moved anymore it would read 260 on the gauge yet its 30 deg lower, Still going to replace the secondary relay, does not come on when the AC is on, ac switch is hooked up and charged fwiw. no codes that i can see.

 

Did you try plugging the secondary wire harness into the primary relay to verfy the fan motor is good ? The primary and secondary relays are identical, so nothing bad would happen. I've done this before to my '94 to check the secondary fan.

 

Good idea, Ill do that first.

 

My 92 still has the sticker on the cluster that sez "these gauges are not analog...blah blah blah"
You gotta go by the digital in the dash for actual temp. Silly sticker, but I can't bring myself to remove it...