1995 LT1 overheating
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From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
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1995 LT1 overheating
I'm working on a 95 conv. with an LT1 auto trans that has an overheating issue. The thermostat and fan relays have been replaced. The fans will come on when the AC is turned on but will not come on when the car gets over 220-230. In fact it will go up to 260 and the fans still do not come on. There is new coolant as well. I'm pretty sure the water pump is working. I can see the coolant level go down in the tank when you increase RPM's and then it returns to top off level at idle. I still need to verify the new t-stat works (not my car). Could the coolant sensor be causing this problem? I don't want the owner driving it at these temps for fear of cracking a head. The car has just shy of 80K miles and no mods to the engine. Thanks for any and all help.
Added: It runs at normal temps when in motion. At a light or stopped at idle the temp climbs up.
Added: It runs at normal temps when in motion. At a light or stopped at idle the temp climbs up.
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St. Jude Donor '08-'09
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St. Jude Donor '10 thru '25
I'm working on a 95 conv. with an LT1 auto trans that has an overheating issue. The thermostat and fan relays have been replaced. The fans will come on when the AC is turned on but will not come on when the car gets over 220-230. In fact it will go up to 260 and the fans still do not come on. There is new coolant as well. I'm pretty sure the water pump is working. I can see the coolant level go down in the tank when you increase RPM's and then it returns to top off level at idle. I still need to verify the new t-stat works (not my car). Could the coolant sensor be causing this problem? I don't want the owner driving it at these temps for fear of cracking a head. The car has just shy of 80K miles and no mods to the engine. Thanks for any and all help.
Added: It runs at normal temps when in motion. At a light or stopped at idle the temp climbs up.
Added: It runs at normal temps when in motion. At a light or stopped at idle the temp climbs up.
Watch the digital temp gauge, and when it reaches approx. 228°F the cooling fans should come on.
At that point most think the fans are broken and the car is overheating, because that analog gauge is dang near to the 260°F mark.
Look close at the analog gauge though, is the needle actually in the shaded area of the gauge?
In any event, that analog gauge does not have a linear scale and it is next to impossible to tell exactly what temp it is reading.
Go by the digital gauge and not worry so much what the analog gauge is reading.
If the digital reads over 235°F and your fans still aren't coming on, then you might have issues.
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From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
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Are you determining these temps by watching the analog or digital temp gauge?
Watch the digital temp gauge, and when it reaches approx. 228°F the cooling fans should come on.
At that point most think the fans are broken and the car is overheating, because that analog gauge is dang near to the 260°F mark.
Look close at the analog gauge though, is the needle actually in the shaded area of the gauge?
In any event, that analog gauge does not have a linear scale and it is next to impossible to tell exactly what temp it is reading.
Go by the digital gauge and not worry so much what the analog gauge is reading.
If the digital reads over 235°F and your fans still aren't coming on, then you might have issues.
Watch the digital temp gauge, and when it reaches approx. 228°F the cooling fans should come on.
At that point most think the fans are broken and the car is overheating, because that analog gauge is dang near to the 260°F mark.
Look close at the analog gauge though, is the needle actually in the shaded area of the gauge?
In any event, that analog gauge does not have a linear scale and it is next to impossible to tell exactly what temp it is reading.
Go by the digital gauge and not worry so much what the analog gauge is reading.
If the digital reads over 235°F and your fans still aren't coming on, then you might have issues.
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From: Rolla Missouri
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St. Jude Donor '10 thru '25
Every new C4 owner that comes along thinks their car is over heating.
Of course, sometimes they are.
But more times than not, they didn't have the serious problem they thought they had.
Late model C4 temps. Even though some don't like them, they are perfectly normal.
Using the digital temp gauge.
Sitting still and not moving
Normal temp range: 215°F - 235°F
Moving at any speed above 35mph: 190°F - 200°F
Thread Starter
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From: Out Where the Buses Don't Run, Eglin AFB/ Niceville FL
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Yes, you need to do that.
Every new C4 owner that comes along thinks their car is over heating.
Of course, sometimes they are.
But more times than not, they didn't have the serious problem they thought they had.
Late model C4 temps. Even though some don't like them, they are perfectly normal.
Using the digital temp gauge.
Sitting still and not moving
Normal temp range: 215°F - 235°F
Moving at any speed above 35mph: 190°F - 200°F
Every new C4 owner that comes along thinks their car is over heating.
Of course, sometimes they are.
But more times than not, they didn't have the serious problem they thought they had.
Late model C4 temps. Even though some don't like them, they are perfectly normal.
Using the digital temp gauge.
Sitting still and not moving
Normal temp range: 215°F - 235°F
Moving at any speed above 35mph: 190°F - 200°F
Le Mans Master
Joined: Jan 2006
Posts: 6,564
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From: Woodstock Georgia
The sensor on right head sends to analog gauge only. Sender on the water pump goes to the PCM, and in turn to the digital gauge and fan relays. Might be as simple as the sender on WP.
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From: Big Flats NY
I have been fighting this recently too. It turned out to be the wiring loom that goes into the CTS on the Water pump. I had some loose pin sockets, fixed them and all is well now. You can get a resistance chart for the sensor from Autozone.com to check the sensor, it is what I used to determine that my sensor was good, I then started chasing wires back from the sensor, didn't take too long to see that the socket/plug needed to be replaced. Easy fix. I am assuming that my 94 and your 95 are pretty similar in this way mechanically.
Burning Brakes
Joined: Jul 2006
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From: Chicago Area
Yes, you need to do that.
Every new C4 owner that comes along thinks their car is over heating.
Of course, sometimes they are.
But more times than not, they didn't have the serious problem they thought they had.
Late model C4 temps. Even though some don't like them, they are perfectly normal.
Using the digital temp gauge.
Sitting still and not moving
Normal temp range: 215°F - 235°F
Moving at any speed above 35mph: 190°F - 200°F
Every new C4 owner that comes along thinks their car is over heating.
Of course, sometimes they are.
But more times than not, they didn't have the serious problem they thought they had.
Late model C4 temps. Even though some don't like them, they are perfectly normal.
Using the digital temp gauge.
Sitting still and not moving
Normal temp range: 215°F - 235°F
Moving at any speed above 35mph: 190°F - 200°F
I have a 95 and I can even think of using the air in traffic. It will boil over. When the car is moving 180, but stand still on a 80 to 100 degree day (or even cooler for that matter) and it just keeps climbing to 240 and beyond. It does it without the AC as well, just takes about 5 minutes longer to get there. I have had to blast the heat in traffic on a hot day. It sucks!
I wish I could get the temps down on this car. I even have the fans coming on at 190 and it don't help...
Oh and it true here as stated to trust the digital over the analog gauge? In my car they are off a bit. I cant remember but I think the Analog runs a little hotter than the digital.
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Back out tot he garage and do some simple testing.
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From: Rolla Missouri
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Really? 235 is NORMAL?
I have a 95 and I can even think of using the air in traffic. It will boil over. When the car is moving 180, but stand still on a 80 to 100 degree day (or even cooler for that matter) and it just keeps climbing to 240 and beyond. It does it without the AC as well, just takes about 5 minutes longer to get there. I have had to blast the heat in traffic on a hot day. It sucks!
I wish I could get the temps down on this car. I even have the fans coming on at 190 and it don't help...
Oh and it true here as stated to trust the digital over the analog gauge? In my car they are off a bit. I cant remember but I think the Analog runs a little hotter than the digital.
I have a 95 and I can even think of using the air in traffic. It will boil over. When the car is moving 180, but stand still on a 80 to 100 degree day (or even cooler for that matter) and it just keeps climbing to 240 and beyond. It does it without the AC as well, just takes about 5 minutes longer to get there. I have had to blast the heat in traffic on a hot day. It sucks!
I wish I could get the temps down on this car. I even have the fans coming on at 190 and it don't help...
Oh and it true here as stated to trust the digital over the analog gauge? In my car they are off a bit. I cant remember but I think the Analog runs a little hotter than the digital.
The information I listed was for a completely stock car.
Sitting at a traffic light the temps will climb until the cooling fans comes on (approx. 228°F)
They should stabilize in the 228°F - 235°F range, and not get any hotter.
My '96 will sit an idle at those temps as long as it sits still.
I know your well aware of some of the long Power Tour lines getting into the venues.
I have sat in those lines in some of the worst heat the south has to offer.
The boiling point for for a factory system (proper coolant/pressure) is just over 260°F
Burning Brakes
Joined: Jul 2006
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From: Chicago Area
But your car is not stock, since it is supercharged.
The information I listed was for a completely stock car.
Sitting at a traffic light the temps will climb until the cooling fans comes on (approx. 228°F)
They should stabilize in the 228°F - 235°F range, and not get any hotter.
My '96 will sit an idle at those temps as long as it sits still.
I know your well aware of some of the long Power Tour lines getting into the venues.
I have sat in those lines in some of the worst heat the south has to offer.
The boiling point for for a factory system (proper coolant/pressure) is just over 260°F
The information I listed was for a completely stock car.
Sitting at a traffic light the temps will climb until the cooling fans comes on (approx. 228°F)
They should stabilize in the 228°F - 235°F range, and not get any hotter.
My '96 will sit an idle at those temps as long as it sits still.
I know your well aware of some of the long Power Tour lines getting into the venues.
I have sat in those lines in some of the worst heat the south has to offer.
The boiling point for for a factory system (proper coolant/pressure) is just over 260°F
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From: Rolla Missouri
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St. Jude Donor '10 thru '25
Well my solution this year was early starts and early venue arrivals. but with that said, Even with the supercharger, if I come in after moving my car can be as low as 173 on the digital. Just because it has the supercharger if I am idling what would the best solution to help keep it cool at idle in traffic??? Does the supercharger really effect temps that much at idle?
But if your temps continue to climb (even after the cooling fans are running), then something about your cooling system isn't optimized for your engine combination.
For a stock car, with the cooling fans running the car should be able to sit and idle for as long as you want without the temps climbing much past 235°F
Burning Brakes
Joined: Apr 2011
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From: College Station Tx
I had the same issue, and found that only one of the two fans was coming on. I found a blown fuse on the 2nd motor. I replaced the fuse and it blew shortly after the motor came on. I then replaced the motor and since then have had no issue with temperature.
Burning Brakes
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From: Chicago Area
Well maybe im just not liking the fact im seeing 230's. just so happens that yesterday my heater control valve split in two and lost all my coolant. I should see a new valve tomorrow so when I get it all back together I'll retest it and see if it rises above 235 at idle...I'm pretty sure if I push in traffic I've seen 240. But then again a lot of times I've been looking at the analog gauge when it gets that hot and not the digital as much and after reading around here most say to go by the digital...but when I've been seeing that analog at the top of the cross hatches I've been shutting it down.
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From: Rolla Missouri
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St. Jude Donor '10 thru '25
Well maybe im just not liking the fact im seeing 230's. just so happens that yesterday my heater control valve split in two and lost all my coolant. I should see a new valve tomorrow so when I get it all back together I'll retest it and see if it rises above 235 at idle...I'm pretty sure if I push in traffic I've seen 240. But then again a lot of times I've been looking at the analog gauge when it gets that hot and not the digital as much and after reading around here most say to go by the digital...but when I've been seeing that analog at the top of the cross hatches I've been shutting it down.
As long as the needle is not actually in the shaded area, your not actually overheating.
Also remember, that analog gauge does not have a linear scale.
When the digital gauge reads 228°F the analog gauge needle will look like it is close to 260°.
But if you look close, the needle will be just short of the shaded area.
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A new summer, and I see (again) many nOOb's overheating threads; like we see the mice threads on the winter.
Preventive maintenance helps this from happening. If your Vette is running above 250, clean the shroud, ensure your cooling system is topped off, burp the system, and learn how the reverse cooling works.
FYI - The LT1 runs hot 220-230.
Preventive maintenance helps this from happening. If your Vette is running above 250, clean the shroud, ensure your cooling system is topped off, burp the system, and learn how the reverse cooling works.
FYI - The LT1 runs hot 220-230.
Melting Slicks
Joined: Aug 2008
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From: Palmdale CA
Well maybe im just not liking the fact im seeing 230's. just so happens that yesterday my heater control valve split in two and lost all my coolant. I should see a new valve tomorrow so when I get it all back together I'll retest it and see if it rises above 235 at idle...I'm pretty sure if I push in traffic I've seen 240. But then again a lot of times I've been looking at the analog gauge when it gets that hot and not the digital as much and after reading around here most say to go by the digital...but when I've been seeing that analog at the top of the cross hatches I've been shutting it down.
