Operating temp
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 36
Likes: 0
From: Venice - Italy
Thanks for your answers. My car stays about 15 degrees more, from 215 to 230... For sure I have to change the fan clutch. But I've also just changed the temp sensor so I have to check if it works properly, I thought that I could measure with IR on water pump...
Race Director
Joined: May 2006
Posts: 18,668
Likes: 2,564
verify that the readings are correct with the IR.
do you get the 230 reading on the highway or at low speeds?
are all the seals between the radiator and the support still there?
is the seal between the radiator support and the hood still there?
do you get the 230 reading on the highway or at low speeds?
are all the seals between the radiator and the support still there?
is the seal between the radiator support and the hood still there?
Thread Starter
Intermediate
Joined: Sep 2018
Posts: 36
Likes: 0
From: Venice - Italy
Good morning! I checked with IR gun pointing the water pump, I read about 215 ° at idle, more or lees the same of the gauge, so the sensors is ok…
the radiator seems work because I read about 195° on the top of if and abput 135 ° on the bottom.
the fun clutch is gone but maybe it's not enought for justify the heating… I must to say that the ext temperature is quite cold here now, about 35-40 °F. I reacj 230° max just in sport drive and about 215 ° on highway at 70 mph
I didn't understand what do you mean with seals and spoiler, I post some pic…
Thank you!
the radiator seems work because I read about 195° on the top of if and abput 135 ° on the bottom.
the fun clutch is gone but maybe it's not enought for justify the heating… I must to say that the ext temperature is quite cold here now, about 35-40 °F. I reacj 230° max just in sport drive and about 215 ° on highway at 70 mph
I didn't understand what do you mean with seals and spoiler, I post some pic…
Thank you!
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Le Mans Master
Joined: Oct 2007
Posts: 7,442
Likes: 968
From: Tennessee/Rhode Island
If you are looking for the factory run temp of about 200 degrees than everything folks have already advised should achieve that temp.
The hottest running SBC C3's, by far, were the 78-79/L-82's from the factory brand new temps of 225 normal and 235-240 on a hot day with AC on like my 78 which routinely ran those temps back in the day when new. After years and years of trial and error, replacing parts, I have found the answer for my car to run moderate operating temps dictated by the thermostat, not the engine. I changed nothing in the cooling system after the OEM L-82 was rebuilt/upgraded in 2014 with into a 425+ Gross HP/L-82 355 and the engine runs perfect at about 175-180 all year long regardless of temperature outside. What did I find and do over all those years:
1. Dewitts aluminum radiator
2. Stewart Stage 2 Aluminum water pump with Robertshaw Modified thermostat-holes in thermostat..you can drill your own in a regular thermostat.
3. A heavy duty cooling L-82 7 blade GM fan-my L-82 had this fan OEM
4, GM/AC Delco Heavy duty themostatically controlled fan clutch-NOT a regular fan clutch that does not engage/disengage with RPM's only
5. Factory chin spoiler
6. Important-1979 ONLY YEAR Option-Heavy duty cooling spoiler extension-I installed this spoiler extension bought from GM dealer in the early 90's and still on my 78 L-82.
7. Radiator seals and insulation on my 78 L-82 are all still there but OEM original and not in great shape. I have experimented with them over the years on their effect of the cooling system and it was marginal at best. Steps 1-6 are much MORE important than the seals/insulation (they are more important on a factory cooling system which is marginal).
I had to use a new thermostat with just 1 hole drilled since the engine would run too cool with the Robertshaw 3 hole thermostat. I run a 180 thermostat and the car runs exactly 180 degrees on the gauge. You can use one/none or all these steps to help your cooling.
The hottest running SBC C3's, by far, were the 78-79/L-82's from the factory brand new temps of 225 normal and 235-240 on a hot day with AC on like my 78 which routinely ran those temps back in the day when new. After years and years of trial and error, replacing parts, I have found the answer for my car to run moderate operating temps dictated by the thermostat, not the engine. I changed nothing in the cooling system after the OEM L-82 was rebuilt/upgraded in 2014 with into a 425+ Gross HP/L-82 355 and the engine runs perfect at about 175-180 all year long regardless of temperature outside. What did I find and do over all those years:
1. Dewitts aluminum radiator
2. Stewart Stage 2 Aluminum water pump with Robertshaw Modified thermostat-holes in thermostat..you can drill your own in a regular thermostat.
3. A heavy duty cooling L-82 7 blade GM fan-my L-82 had this fan OEM
4, GM/AC Delco Heavy duty themostatically controlled fan clutch-NOT a regular fan clutch that does not engage/disengage with RPM's only
5. Factory chin spoiler
6. Important-1979 ONLY YEAR Option-Heavy duty cooling spoiler extension-I installed this spoiler extension bought from GM dealer in the early 90's and still on my 78 L-82.
7. Radiator seals and insulation on my 78 L-82 are all still there but OEM original and not in great shape. I have experimented with them over the years on their effect of the cooling system and it was marginal at best. Steps 1-6 are much MORE important than the seals/insulation (they are more important on a factory cooling system which is marginal).
I had to use a new thermostat with just 1 hole drilled since the engine would run too cool with the Robertshaw 3 hole thermostat. I run a 180 thermostat and the car runs exactly 180 degrees on the gauge. You can use one/none or all these steps to help your cooling.
Last edited by jb78L-82; Dec 29, 2018 at 07:43 AM.
Race Director
Joined: May 2006
Posts: 18,668
Likes: 2,564
You appear to be missing the seal between the hood and radiator support. I cannt see around the rest of the radiator but here is an example seal kit. If your fan clutch freely spins with the engine cold and off it should be replaced.
https://www.paragoncorvette.com/p-35...-seal-kit.aspx
https://www.paragoncorvette.com/p-35...-seal-kit.aspx
Team Owner
Joined: Jan 2006
Posts: 39,347
Likes: 171
From: Into the Mystic And yet, despite the look on my face, you're still talking TN
St. Jude Donor '09 thru '25
If you are looking for the factory run temp of about 200 degrees than everything folks have already advised should achieve that temp.
The hottest running SBC C3's, by far, were the 78-79/L-82's from the factory brand new temps of 225 normal and 235-240 on a hot day with AC on like my 78 which routinely ran those temps back in the day when new. After years and years of trial and error, replacing parts, I have found the answer for my car to run moderate operating temps dictated by the thermostat, not the engine. I changed nothing in the cooling system after the OEM L-82 was rebuilt/upgraded in 2014 with into a 425+ Gross HP/L-82 355 and the engine runs perfect at about 175-180 all year long regardless of temperature outside. What did I find and do over all those years:
1. Dewitts aluminum radiator
2. Stewart Stage 2 Aluminum water pump with Robertshaw Modified thermostat-holes in thermostat..you can drill your own in a regular thermostat.
3. A heavy duty cooling L-82 7 blade GM fan-my L-82 had this fan OEM
4, GM/AC Delco Heavy duty themostatically controlled fan clutch-NOT a regular fan clutch that does not engage/disengage with RPM's only
5. Factory chin spoiler
6. Important-1979 ONLY YEAR Option-Heavy duty cooling spoiler extension-I installed this spoiler extension bought from GM dealer in the early 90's and still on my 78 L-82.
7. Radiator seals and insulation on my 78 L-82 are all still there but OEM original and not in great shape. I have experimented with them over the years on their effect of the cooling system and it was marginal at best. Steps 1-6 are much MORE important than the seals/insulation (they are more important on a factory cooling system which is marginal).
I had to use a new thermostat with just 1 hole drilled since the engine would run too cool with the Robertshaw 3 hole thermostat. I run a 180 thermostat and the car runs exactly 180 degrees on the gauge. You can use one/none or all these steps to help your cooling.
The hottest running SBC C3's, by far, were the 78-79/L-82's from the factory brand new temps of 225 normal and 235-240 on a hot day with AC on like my 78 which routinely ran those temps back in the day when new. After years and years of trial and error, replacing parts, I have found the answer for my car to run moderate operating temps dictated by the thermostat, not the engine. I changed nothing in the cooling system after the OEM L-82 was rebuilt/upgraded in 2014 with into a 425+ Gross HP/L-82 355 and the engine runs perfect at about 175-180 all year long regardless of temperature outside. What did I find and do over all those years:
1. Dewitts aluminum radiator
2. Stewart Stage 2 Aluminum water pump with Robertshaw Modified thermostat-holes in thermostat..you can drill your own in a regular thermostat.
3. A heavy duty cooling L-82 7 blade GM fan-my L-82 had this fan OEM
4, GM/AC Delco Heavy duty themostatically controlled fan clutch-NOT a regular fan clutch that does not engage/disengage with RPM's only
5. Factory chin spoiler
6. Important-1979 ONLY YEAR Option-Heavy duty cooling spoiler extension-I installed this spoiler extension bought from GM dealer in the early 90's and still on my 78 L-82.
7. Radiator seals and insulation on my 78 L-82 are all still there but OEM original and not in great shape. I have experimented with them over the years on their effect of the cooling system and it was marginal at best. Steps 1-6 are much MORE important than the seals/insulation (they are more important on a factory cooling system which is marginal).
I had to use a new thermostat with just 1 hole drilled since the engine would run too cool with the Robertshaw 3 hole thermostat. I run a 180 thermostat and the car runs exactly 180 degrees on the gauge. You can use one/none or all these steps to help your cooling.
Team Owner
Joined: Jan 2006
Posts: 39,347
Likes: 171
From: Into the Mystic And yet, despite the look on my face, you're still talking TN
St. Jude Donor '09 thru '25
On www.rockauto.com, there are different brands, I took acdelco
Le Mans Master
Joined: Oct 2007
Posts: 7,442
Likes: 968
From: Tennessee/Rhode Island
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
If you hold the engine at a steady 2-300rpm for 15-20 seconds if your bottom hose is collapsing then youll see it.
taking a water hose and from the backside blasting the gunk out of the fins makes a big difference. Youd be surprised how much stuff gets packed inside there. Do it once a yr on all my cars, fan clutch comes on less often and ac seems to like it
taking a water hose and from the backside blasting the gunk out of the fins makes a big difference. Youd be surprised how much stuff gets packed inside there. Do it once a yr on all my cars, fan clutch comes on less often and ac seems to like it
Team Owner
Joined: Jan 2006
Posts: 39,347
Likes: 171
From: Into the Mystic And yet, despite the look on my face, you're still talking TN
St. Jude Donor '09 thru '25
Le Mans Master
Joined: Oct 2007
Posts: 7,442
Likes: 968
From: Tennessee/Rhode Island
Team Owner
Joined: Jan 2006
Posts: 39,347
Likes: 171
From: Into the Mystic And yet, despite the look on my face, you're still talking TN
St. Jude Donor '09 thru '25
They very honestly told me their sending units would not be correct, either. They make a gizmo to dial back the needle from the back of the gauge but I really do not want to remove that dash panel. I just live with it reading about 20* high.