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I am driving my baby Red in the 4th of July parade here locally. Last year she ran really, really hot and overheated just at the end of the 1.5 mile parade route. Under normal driving circumstances, she does run a little hot (220), but last year she red lined and my Dad had me pull her over to cool down even with the heat on.
What is the best coolant you suggest as she needs to be topped off?
the general rule is, any approved ethylene glycol based coolant can be used in all GM vehicles 1995 and newer. So if you are adding to existing coolant (assuming that is what is in your car), make sure you add ethylene glycol based fluid. Maybe it's time to do a flush and replace all of it. Don't be fooled by color, there are green/blue colored coolants that are ethylene glycol based.
Here's good video that explains the development of Dex-Cool
Make sure your condenser and radiator are not clogged. It is a very common issue with C5 corvettes.
For a parade situation run the air conditioner! This will force the fans to run on low speed. Otherwise the fans turn on above 220° normally and you have zip,zero,nada airflow at such a low speed.
Make sure your condenser and radiator are not clogged. It is a very common issue with C5 corvettes.
For a parade situation run the air conditioner! This will force the fans to run on low speed. Otherwise the fans turn on above 220° normally and you have zip,zero,nada airflow at such a low speed.
Last year we did both. I am thinking of starting the A/C sooner than we did - mostly because it will be nearly 100!
I am driving my baby Red in the 4th of July parade here locally. Last year she ran really, really hot and overheated just at the end of the 1.5 mile parade route. Under normal driving circumstances, she does run a little hot (220), but last year she red lined and my Dad had me pull her over to cool down even with the heat on.
What is the best coolant you suggest as she needs to be topped off?
It's summer, and water gets rid of the heat better than antifreeze, so top off with distilled water. Then before winter, drain, flush and refill with a 50/50 Dexcool/distilled water mix - Dexcool being the factory approved and recommended coolant for the C5. You may be surprised at the gunk that comes out when you drain and flush.
I was a water pump engineer for 5yrs (Ford) and I've owned a C4 and a C5.
Here is what I suggest....
1. Clean the AC condenser and radiator. You might take the top plastic shroud off so you can get down in there. Also there are wands you can buy for hooking up to air and a water hose (I bought them)
2. 30% dexcool 70% distilled water. And burp the system of air. A good way to help prevent air from being trapped is to fill the degas bottle slowly. Give the air little resistance to "burp". (I do that on stubborn cars and its often effective)
3. Don't run the AC... *IF* it starts to get too hot turn the heater on blowing through the top vents.
Dex-Cool specification coolants will all be adequate. Which brand you buy does not matter much. AC Delco, Prestone, others are fine.
Your cooling system is not working properly if your car is overheating. You should be able to idle forever without issue.
Debris partially blocking the radiator is fairly common. Get under the car and look up into where the air enters the radiator. Gentle blasts of compressed air from the back side are the best way to dislodge debris without pushing stuff into the fins and making it harder to remove. From the top side you might put a small vacuum hose attachment between the radiator and the A/C condenser to remove that debris. Wands for spraying water are also useful.
If your system has never been flushed it MIGHT be beneficial to do so given the age of these cars.
Good luck!
But redline is redline. Radiators do lose effectivity as they age, incorrect coolant can be mixed in by accident, and thermostats can and do get sticky. By all means clean the radiator — and in your situation I would suggest both inside and out (i.e. flush). Full fill with known good coolant, and a good’burp’ procedure. Then a long-ish driveway idle test to see how it does.
I’ve tried both Water-wetter and Engine-Ice (not at the same time) in a vehicle known for cooling issues. Neither made a whit of difference in temperature.
Any dexcool coolant is fine. As others have said. clean the radiator out really well. Make sure to blow it out from the back. A coolant flush would be a good idea if you haven't done so recently. The parade is only 1.5 miles, so you really shouldn't be overheating.
I wish more C5 owners would learn this. The stock fans don't even come on until 230+.
Spot on, again. She did say it "redlined." But-correct me if I'm wrong-Doesnt the stock C5 coolant have to reach 235° before the fans switch to high speed, as in on at 235°, off at 220°? Sounds like she needs to flush/replace coolant, ensure condenser and radiator are clear, and perhaps install a new thermostat.....
Main cause and most overlooked is cleaning the radiator and condenser fins. You can get the big stuff out from underneath just using a vacuum tube, but removing the top cover, 4 bolts, gives you access for wands; both air and water.
The engineer might be “right”, but I wouldn’t drive in 100° heat with the heater blowing, lol, so turn on the AC to keep the fans running.
Radiator Genie - Water & Air Cleaning Wands for High Efficiency Cooling Systems and Radiators - Blow Out / Wash Out Kit https://a.co/d/4vvuj76
I was a water pump engineer for 5yrs (Ford) and I've owned a C4 and a C5.
Here is what I suggest....
1. Clean the AC condenser and radiator. You might take the top plastic shroud off so you can get down in there. Also there are wands you can buy for hooking up to air and a water hose (I bought them)
2. 30% dexcool 70% distilled water. And burp the system of air. A good way to help prevent air from being trapped is to fill the degas bottle slowly. Give the air little resistance to "burp". (I do that on stubborn cars and its often effective)
3. Don't run the AC... *IF* it starts to get too hot turn the heater on blowing through the top vents.
^^^ This. As another poster mentioned, water is able to dissipate more heat than coolant. A higher percentage of water will help remove more heat. I know the fans come on with AC running, but running the AC also increases the temperature of the air moving across the radiator. Running the heater fan can remove a fair amount of heat.
Thank you everyone for all the advice! I am going to start with the coolant (it is still a little low), then I will look at cleaning out the radiator and condenser after the parade.
I know this car needs to some work. My Dad took amazingly good care of it, but since he was in and out of the hospital since the last 4th of July parade (and later passed), not much has been done with her since. There will be more questions as I haven't worked on a Corvette in nearly 17 years (C4 rebuild).
Op, you said the system "was a little low" and were going to add coolant.
Make sure it's full to the correct level as it takes a full system to dissipate the heat correctly. Any air in the system hinders the effectiveness. This is why 'burbing' the system is so important. Don't stop with the burping until you are 100% certain all of the air is purged.
Also check the mix percentage. Yes straight water is more efficient, but do you have the time to flush all of the old out and refill before the fourth? Buy the tester for the mix percentage. Any auto parts store will have them. Test before you add anything! If the mix is low, add some 50/50 or maybe some concentrate if really low. Distilled water if the mix is to strong. Just like most everything else, antifreeze will degrade/weaken over time so having the tester is good for having for the long term and all of your vehicles.
Op, you said the system "was a little low" and were going to add coolant.
Make sure it's full to the correct level as it takes a full system to dissipate the heat correctly. Any air in the system hinders the effectiveness. This is why 'burbing' the system is so important. Don't stop with the burping until you are 100% certain all of the air is purged.
Also check the mix percentage. Yes straight water is more efficient, but do you have the time to flush all of the old out and refill before the fourth? Buy the tester for the mix percentage. Any auto parts store will have them. Test before you add anything! If the mix is low, add some 50/50 or maybe some concentrate if really low. Distilled water if the mix is to strong. Just like most everything else, antifreeze will degrade/weaken over time so having the tester is good for having for the long term and all of your vehicles.
At this point, I would just add water and see how the engine cools before the parade. After the parade start with cleaning the debris away from the top of the condenser. C5s gather a lot of grass and other debris at the top of the AC condenser that can only be removed by using a vacuum cleaner and brushes from under the car. Then flush the cooling system and refill it with 50/50 mix of Dex and water. Another thing to check are the two seals that seal the radiator duct to the AC condenser. They come loose over time and tend to let air flow to the sides of the AC condenser and into the engine compartment. You can usually tell if they have come loose as they can be seen with the hood open if you look down past the headlight to where the side of the AC condenser is seen. They will look like small snakes sticking to the side. This only affects cooling when moving at speeds above 35 mph.
I don't like the idea of anything less than a 50-50 mix of water and antifreeze. If your travels take you to a colder location, and they have a cold wave hit, you can ruin an engine. I have a family member that lives in Ft. Lauderdale, Florida. This past Christmas he visited relatives in Northern Ohio. One morning he went out to start his 6.0 LS truck, and the engine wouldn't turn over!!! The engine had frozen enough to seize the water pump. He got really lucky, because it was caught in time. Towed to a local garage, and thawed it out overnight. Didn't even pop a freeze plug. If he wouldn't have driven it that day, another 24 hours and block would've cracked. It's not worth it. A C5 shouldn't overheat if all is well in the fan/cooling system. Mixing too little antifreeze with water is a bandaid that could ruin the engine given the right situation......
Best Coolant?
