84 overheats
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 33
Likes: 0
From: Los Altos California
84 overheats
I'm a new member of this forum so this is my first post.
I have an 84 Corvette 4+3 that I purchased new that's been sitting in my garage for about 10 years and I've started getting it back into top shape.
I just installed a new 2 row aluminum radiator and a 160 degree thermostat. When I start it and let it idle, the thermostat opens at about 160 degrees and then the temperature just keeps rising until it turns on the electric fan at about 240 degrees. When I drive it down the freeway, it will cool down to about 190 degrees (the outside temperature is about 80). The oil temp is 195.
Any ideas of how I can keep the temperature close to 200 degrees instead of always rising to 240+ degrees? If I simply change the fan temperature switch to a 200 degree switch will I be fine?
Thanks in advance for your help.
I have an 84 Corvette 4+3 that I purchased new that's been sitting in my garage for about 10 years and I've started getting it back into top shape.
I just installed a new 2 row aluminum radiator and a 160 degree thermostat. When I start it and let it idle, the thermostat opens at about 160 degrees and then the temperature just keeps rising until it turns on the electric fan at about 240 degrees. When I drive it down the freeway, it will cool down to about 190 degrees (the outside temperature is about 80). The oil temp is 195.
Any ideas of how I can keep the temperature close to 200 degrees instead of always rising to 240+ degrees? If I simply change the fan temperature switch to a 200 degree switch will I be fine?
Thanks in advance for your help.
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
Welcome
I'm assuming you bleed the system?
Between cyl # 6 and #8 is a sensor in the head that tells the fan to turn on at a certain temperature. I've replace mine with one that turns the fan on at 195 degrees. Most times my temp runs 180- 210.
I'm assuming you bleed the system?
Between cyl # 6 and #8 is a sensor in the head that tells the fan to turn on at a certain temperature. I've replace mine with one that turns the fan on at 195 degrees. Most times my temp runs 180- 210.
Racer
Joined: Jul 2010
Posts: 261
Likes: 0
From: Spokane WA
You can buy a manual fan switch from corvette central or ecklers or mid america and is an easy install but don't forget to turn the fan on. I personally let it run allm the time and it stays cool. On the highway it stays around 165 to 185 and in traffic will reach 205.
Manual fan switch
Manual fan switch
Instructor
Joined: Jun 2011
Posts: 182
Likes: 0
From: Bowling Green Ky
give it some thought before you install a constant fan, it uses horsepower, shortens life of the fan motor, plus, at highway speeds the elect fans are not a benefit and not additive to the air mass flowing through the radiator.
in 4 years, I can almost count on one hand the times my fans have come on. GM designed the system for good reasons.
if you are running that high there is another problem.
jc
in 4 years, I can almost count on one hand the times my fans have come on. GM designed the system for good reasons.
if you are running that high there is another problem.
jc
Instructor
Joined: Jul 2009
Posts: 201
Likes: 0
From: Orland Hills ILLINOIS
Well I have an 84 myself and that sounds pretty normal.
I installed an all aluminum 2 row radiator myself this summer.
Before I was running about 220 all the time. Now I am at 190 when driving.
Yes it creeps up when sitting or idling but fans kick on at 228 for me.
When driving it runs at 188 to 190 on a 80' day.
It was running hot all the time before. I have a thermostat thats 185 so mine is right on
I dont think yours is a problem. I also own a 2011 Camaro and I have seen that run to 225.
These are all normal operating conditions.
Kevin
I installed an all aluminum 2 row radiator myself this summer.
Before I was running about 220 all the time. Now I am at 190 when driving.
Yes it creeps up when sitting or idling but fans kick on at 228 for me.
When driving it runs at 188 to 190 on a 80' day.
It was running hot all the time before. I have a thermostat thats 185 so mine is right on
I dont think yours is a problem. I also own a 2011 Camaro and I have seen that run to 225.
These are all normal operating conditions.
Kevin
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
When you replaced the radiator, did you clean the A/C condensor? Over the years, there will be dirt and debris that will clog the openings between the tubes and fins. This will reduce the airflow going thru to the radiator. The C4 is called a "bottom breather" as the only cooling air comes up from the bottom of the car behind the front license plate.
Also did you flush the cooling system before installing the new radiator? It's entirely possible that there is some corrosion in the cooling system that is not allowing a full flow of coolant. Did you install new radiator hoses? Could be that the lower hose is collapsing to where the flow of coolant is reduced. Is the water pump new? The impeller in the water pump could be corroded to where it won't push enough coolant through the system.
I also agree that there is no real reason to mess with the fan operation. The C4 cooling system is designed to run warmer to help with emissions. Seeing coolant temps of 195 to 215 or so is perfectly normal for a cooling system in good condition. The later C4's can run even hotter with temps in the 210-228 range before a secondary fan even turns on.
Also did you flush the cooling system before installing the new radiator? It's entirely possible that there is some corrosion in the cooling system that is not allowing a full flow of coolant. Did you install new radiator hoses? Could be that the lower hose is collapsing to where the flow of coolant is reduced. Is the water pump new? The impeller in the water pump could be corroded to where it won't push enough coolant through the system.
I also agree that there is no real reason to mess with the fan operation. The C4 cooling system is designed to run warmer to help with emissions. Seeing coolant temps of 195 to 215 or so is perfectly normal for a cooling system in good condition. The later C4's can run even hotter with temps in the 210-228 range before a secondary fan even turns on.
Thread Starter
Intermediate
Joined: Sep 2011
Posts: 33
Likes: 0
From: Los Altos California
Thanks everyone for the inputs. I did flush the system before I changed the radiator but I forgot to clean the A/C condensor and the oil cooler that's in front of the condensor. The old radiator was filthy so I'm sure that the items in front of the radiator will be even worse. That'll be my task for the coming weekend.
Once again, thanks for the inputs.
Bob
Once again, thanks for the inputs.
Bob
Platinum Supporting Vendor
Joined: Feb 2004
Posts: 1,772
Likes: 37
From: Sawyer MI
I'm a new member of this forum so this is my first post.
I have an 84 Corvette 4+3 that I purchased new that's been sitting in my garage for about 10 years and I've started getting it back into top shape.
I just installed a new 2 row aluminum radiator and a 160 degree thermostat. When I start it and let it idle, the thermostat opens at about 160 degrees and then the temperature just keeps rising until it turns on the electric fan at about 240 degrees. When I drive it down the freeway, it will cool down to about 190 degrees (the outside temperature is about 80). The oil temp is 195.
Any ideas of how I can keep the temperature close to 200 degrees instead of always rising to 240+ degrees? If I simply change the fan temperature switch to a 200 degree switch will I be fine?
Thanks in advance for your help.
I have an 84 Corvette 4+3 that I purchased new that's been sitting in my garage for about 10 years and I've started getting it back into top shape.
I just installed a new 2 row aluminum radiator and a 160 degree thermostat. When I start it and let it idle, the thermostat opens at about 160 degrees and then the temperature just keeps rising until it turns on the electric fan at about 240 degrees. When I drive it down the freeway, it will cool down to about 190 degrees (the outside temperature is about 80). The oil temp is 195.
Any ideas of how I can keep the temperature close to 200 degrees instead of always rising to 240+ degrees? If I simply change the fan temperature switch to a 200 degree switch will I be fine?
Thanks in advance for your help.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
