[DOES ANYONE HAVE AN OVERHEATING ISSUE WITH A BASE ENGINE C5? OUR CAR RUNS AT 240F IN TRAFFIC. I HAVE CHECKED ALL OF THE COMMON ITEMS, IE: COOLANT, CAP, FANS ( COME ON AT 205F) DEBRIS IN THE FRONT OF RADIATOR, ENGINE TIMING, ETC. DO AFTER MARKET MANUAL OVER RIDE UNITS WORK TO TURN FANS ON EARLIER? YOUR ASSISTANCE IS APPRECIATEDFONT="Arial Narrow"][/FONT]

 

A properly operating C5 should NOT over heat in traffic. The normal operating range for Coolant temp is 210-230. The engine will easily survive in that range. Especially if it hot and humid out.


IF,,, you want to lower the cooling system operating temp, you need a 160 deg thermostat installed and have the PCM reporgrammed to turn the fans on earlier and stay on longer.

Before you do that, answer the following questions:

Have you checked the area "BETWEEN" the AC Condensor and the Radaitor???? That area can fill up with dead grass and sand. Take the black plastic cover off and look down between the two radiators and see if its full of trash/grass.

Have you used a garden hose and back flushed the outside radiator and condensor cooling fins to flush out all the sand and dirt that builds up over time???

Have you checked to see if the cooling system is properly PRESSURIZED when it hot? There is an updated resivour cap that raises the cooling system pressure a couple of pounds. See if the big hoses are tight when the engine is up to temp.

Have you actually checked the BOILING POINT of the DEXCOOL / water mixture and made sure it at least above 250 deg?

Have you changed the Thermostat?

Have you made sure that your fans are properly operating on high speed when your above 235 and or the AC is ON??

Last but not least. If all of the above is done and it still overheats, the inside tubes of the radiator could be clogged and the unable to flow the correct coolant through the radiator. You woud have to remove the radiator and have it tested to check that.

Bill

 

Does the temp go back to normal range once you start moving again?

 

Hot running C5 and newer Corvettes is a common occurrence. My 1997 stock with M6 is located at our vacation home in the SE corner of the greater Phoenix area. I have driven it down there through all four seasons so it goes with out saying that I have also seen my car get hot. I think 240 is higher then I have experienced though. You seem to have a good handle on all the common sense over heat causes. Have you owned the car since new? Where do you drive it? Manual or automatic? At what outside air temps are you experiencing 240 temps? The manual cars run a little cooler as they do not have a transmission cooler/heat exchanger in the rad. You might want to investigate a product called Water Wetter. It is a coolant additive that changes the H2O molecule into one that has the ability to scavenge more heat. I have never used it but I know that Baja and desert racers do to help deal with the desert extremes. Whatever you do, DO NOT put a lower temp. stat. in the car thinking that will solve the problem. It will make things worse. The hotter the outside air temp gets, the more important the "Closed Duration" of the thermostat becomes in the over all "Cooling Cycle". By putting a lower temp stat in the car, you shorten the closed thermostat duration which inherently shortens the time that the coolant stays in the Rad. Your intention and ultimate goal is to keep that coolant in the rad as long as possible during the cooling cycle so that when the stat does open, the coolant that is being introduced to the engine is as cool as it can be. I have seen adds for a after market system that has a key fob style RF remote that allows you to turn the cooling fans on earlier then the car would normally do on it's own. If you are looking to try something that is non-invasive and comparatively stock in operation, I would start there. Best of luck. I will follow your thread to see what you found out.

 

Bill: I thank you for the input. I have tried changing the thermostat out to both a 180F and the 160F and had very little effect. I have tried wetting agents and different anti freezes but with very little change. I am the second owner and the car has always had these issues but seam to be getting worse. I also tested the coolant for exhaust gases to make sure there were no internal engine issues and found none. The entire front cooling surfaces have been pressure washed and appear to be clear of debri. The only thing I have not tried is the higher pressure radiater cap. I will do that today. Again, thanks for the assistance.

 

FYI: I do live in Southern California but the problem exiats even in the Winter, lol if you can call 75F in Feb Winter.

 

TVCARMAN and EMTPRESCUE "I Hate You" (buried up to my ears in Boston here)

 

It might be time to get a new radiator. It's very possible some of the internal coolant paths could be blocked and are instead trapping coolant, preventing the cooled coolant from passing through to the engine.

 

The car is a 2003 with only 45,000. Would it be normal for the car to require a new radiator when it has had yearly service?

 

I understand. I spent a year in Chicago during Grad school and thus, why I live here. Hope you warm up soon

 

It's an 11 year-old radiator. They only last so long. Mine had annual service as well but developed a crack at 70k.

 

C5's run hot expecially when not moving, They are bottom feeders and without moving air the fans will only get so cold. Assuming your waterpump is working correctly I would consider a New/Larger radiator. they can get pricy but they are well worth the money. Dewitts and RonDavis make a great radiator that is a direct replacment and a upgrade for the stock, they are a little pricy just a FYI. when its time to change mine that is the route im going.

might read a little on a LS2 waterpump as well I thought i heard something about they are a little better.

S

 

Thank you for the reply. I have looked into a new and larger capacity radiator and yes, they are pricey but not even close to the cost of an engine. Have a good one.

 

"QUOTE" I pressure washed the radiator!!!!



Please make sure that you didnt smash over the cooling fins on the radiator?????????/

NEVER pressure wash a radiator!!! MAKE SURE THE FINS ARE NOT BENT OVER!!

Pull the radiator out and have it flow tested.

While it is out make sure the AC condensor is clean and free to flow air.

 

I don't see where the above question was answered. If temps are fine driving, especially hard driving, the radiator is not the problem. The engine burns more fuel (creates more heat) under throttle than at idle.
If it only gets hot (240) at idle or in traffic, it's a fan problem. Most scanners can turn the fans on low and high speeds with the key on engine off. Make sure both fans work at low and high speeds. If they do, make sure you have battery voltage at the motors on high speed. Poor grounds or bad contacts will give you slow running fans that won't blow fuses (Similar to a car with a dim headlamp).