Cooling Fans
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
From the 96 FSM Page 6-639
AC off
Lo- 219 degrees
Hi- 228 degrees
AC on
Lo AC head pressure > 189
Hi AC head pressure > 225
AC off
Lo- 219 degrees
Hi- 228 degrees
AC on
Lo AC head pressure > 189
Hi AC head pressure > 225
Hman1987,
Your understanding of how your fans work sounds like it has been confused by all the differences between the C4 years.
As mentioned above by a few:
1. the 1996 LT1 has two fans.
2. BOTH fans should run together (i.e. at the same time).
3. With AC OFF, BOTH fans should run at 'slow' speed when the digitial coolant gauge hits or exceeds 228 F.
4. With AC OFF, both fans should run at 'high' speed when the digital coolant guage hits or exceeds 236 F.
5. With AC ON, both fans should run at 'slow' speed almost immediately.
6. With AC ON, if EITHER the digital coolant gauge reads above 236 F -OR- the AC pressure exceeds a pre-set pressure (typically hit during hot weather), both fans should run at 'high' speed.
If only one fan is running at any time, either one of the 3 relays has gone bad (on the driver side of the radiator cover) -or- the non-running fan motor has gone bad -or- there is a wiring problem.
Your understanding of how your fans work sounds like it has been confused by all the differences between the C4 years.
As mentioned above by a few:
1. the 1996 LT1 has two fans.
2. BOTH fans should run together (i.e. at the same time).
3. With AC OFF, BOTH fans should run at 'slow' speed when the digitial coolant gauge hits or exceeds 228 F.
4. With AC OFF, both fans should run at 'high' speed when the digital coolant guage hits or exceeds 236 F.
5. With AC ON, both fans should run at 'slow' speed almost immediately.
6. With AC ON, if EITHER the digital coolant gauge reads above 236 F -OR- the AC pressure exceeds a pre-set pressure (typically hit during hot weather), both fans should run at 'high' speed.
If only one fan is running at any time, either one of the 3 relays has gone bad (on the driver side of the radiator cover) -or- the non-running fan motor has gone bad -or- there is a wiring problem.
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
The suck part of all this, as I see it, is that one beneficial feature of the LT-1 is the reverse-cooling, that puts cooler coolant to the heads first, enabling operation at lower cc temps and slightly higher comp ratio. Yet, at the same time, factory set the cooing fans to not kick in until the coolant was much hotter than a standard passenger vehicle stat temp of 195. Kind of defeats the purpose and offsets the benefit of the reverse-cooling, to set the thing up run hotter. Running hotter like that makes more knock, causing timing retard and power loss, and loss of abiity to take full advantage of LT1's capabilities.
Last edited by ChrisWhewell; Mar 4, 2009 at 07:49 AM. Reason: because I can
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
If I keep at highway speeds, there's no issue, but sitting at a standstill the temp creeps up in to the 230 range eventually. Then if one gets on the highway it cools down after about 5 miles of driving. I'm not complaining, just observing. Although it's a redundant statement I'll say it anyhow: these cars weren't designed to sit still !!
Race Director
Joined: Oct 2005
Posts: 11,771
Likes: 177
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
If your sitting still at a traffic light, there is no airflow moving across the radiator.
Airflow moving across the radiator is what dissipates the heat. Once the temp. reaches the pre-programmed level, your fans kick on and the temp
will begin to drop until the temp. reaches another pre-programmed level and they will shut off. This cycle will continue as long as you sit there.
Even though some people think those programmed on/off fan settings are too hot, that is the way they were designed.
If that is too hot for you, you will need to make modifications to your cooling system design. It can and has been done.
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
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