The car has been stored while I have been moving. I have just now been able to drive it some. I am having overheating issues. Without using the ac it runs around 180 degrees. After turning on the ac it heats up to 210 rather quickly. It has a 160 * thermostat, (it's a newly rebuilt engine) Oversized fan(higher cfm) 2 bottles of Wetter Water . It appears to have newer, possibly larger radiator..The only option I see now is to pull the radiator and have it cleaned or replace it.. Anybody have any ideas???

 

180 is cool for normal running. 210 is not hot either.

If the AC is coming on, the fan should also, can you verify that is happening first

 

"New" or "rebuilt" engines can also have an effect on temperature due to friction and push the temperature higher during break-in. Like Vader86 suggested the 210* numbers are quite normal for the L98. The fans working is very important so be sure they are okay.

"Water Wetter" is great stuff and I have used it many times before.

One thing that I find trouble with is "how much anti-freeze do you Need versus what they normally fill your car with"? Most places around here use 50/50 anti-freeze to water and that may be okay for some. I live in Northern Virginia and we don't get very cold like other parts of the country. Here cooling is more important than freeze protection. In my Corvettes I run 70% distilled water and 30% anti-freeze which combined with a pressurized cooling system it should be sufficient for my area. I don't know how often it Freezes in Texas so I hesitate to suggest a ratio.

Maintaining your radiator is an important task often overlooked in our busy lives. It is really important that you maintain the cooling system by re-freshing the coolant. Every Five years the system should be drained, flushed and refiled with a new coolant. I also replace the thermostat, radiator cap and if needed the hoses. If your cooling system leaks out the engine can be damaged, we all know someone who overheated their engine and warped their cylinder heads. With regular maintenance the cooling system will likely never be a problem for you.

If you have an aluminum Radiator and Condenser they too can be cleaned. "Coil Cleaner" is sold at home improvement stores and even amazon. This cleaner will dissolve the corrosion on any aluminum surface (that is not anodized) and restore it to like new condition. This is done when we have our home cooling systems serviced as the tech will spray the condenser and let it set then they wash it off with running water from a hose (not pressurized water). When was the last time somebody cleaned their condenser on their Corvette? It is not hard and makes a difference!

Best regards,
Chris

 

Is the coil cleaner for the inside or out side of the radiator?

 

Check to see if the fan in front of the radiator is coming on, depending on the year you may have one or not. My fan was fried and after replacing it, I run 200* in stop and go with the AC on.. I have an 85 - 2 fans... Driving it drops to 180.

 

250 is over heating. 210 is not.

 

Well said there Cruisinfanatic!!

I use coil cleaner on the center of front and rear of both condenser and radiator, any aluminum surface will be free of corrosion and transfer heat better. Just be careful to not get the stuff on any painted surfaces. People here on the forum have tried the "Foaming" type coil cleaner and found it did not do much foaming. I would use the plain old coil cleaner. I also tinker with welding Aluminium and if you weld aluminum you must remove ALL corrosion prior to welding it. I bought some welding type aluminum cleaner and it is Phosphoric acid if I am not mistaken but it does a real number on aluminum as well.

Fan operation is critical to your Corvette operating this time of year. I have the B4P (?) option on my 1988 and it is a pusher fan mounted in front of the radiator and then the second fan behind the radiator. There is a temperature switch mounted on the left cylinder head between cylinders 1 and 3 on my car. If you ground the single wire going to the switch the pusher fan will come on from what I have been told. Frequently the little connector dries out and will not hold the wire on on the switch and you loose half of the cooling power.

Be sure that your Fan Relays are working, if you have the FSM you can test them. I replaced them all on my Corvette and keep a spare in my glove box. On my 1988 C4 the fuel pump relay and the Fan relays are one in the same model/number.

When the fans are running you should measure the voltage and be sure they have good clean connections to power. Grounds are very important in any car, be sure that your fans cycle on normally with just heat and then try them on the Air Conditioning mode. I replaced a V6 engine once because it overheated out of the blue. You are smart to be concerned when you see temperatures like you did, they seem high compared to older vehicles. Newer cars run hotter as part of their emissions systems. the L98 was notorious for scaring people who were not expecting it to get as hot as it does.

The L98 does not have any major trouble at getting the air out when filling the coolant system. Sometimes a bit of air can get trapped and cause issues until it is removed. Some forum members have reported successful removal of air by filling the cooling system while the front of the car is on a set of ramps. You want to be sure that you get all the air our of the system.

I have seen cars that had serious overheating issues that were caused by the old "More is Better" attitude. People had put close to 100% anti-freeze thinking it would improve their cooling. Proper ratios of anti freeze and distilled water are very important. If an old radiator cap can't hold 16 Pounds pressure the car will over heat more easily. This is why I suggest a good maintenance program for Corvettes Cooling systems. I am also a strange one that maintains the battery every year...

Good Luck and try to stay cool out there! It is 100* in Washington D.C. today.

Chris

 

Also. after I stop the car, turn off the engine, you can hear the water boiling (girgling) and there is some discharge from the radiator overflow.. Should the fan continue to run to cool the engine even after the engine is turned off?

 

Hello dozerman1,

When the systems are working properly you should not hear any boiling from the coolant system. If there is "some discharge from the radiator overflow" you are probably running the car low on coolant.

When a car is started and the thermostat is open coolant is circulating to the radiator and back to the engine block. As the engine gets warmed up the pressure rises in the cooling system (IF it is a sealed system). The radiator cap aids in keeping the coolant from boiling by raising the boiling point. As the coolant gets hot and expands it will be too much volume for the cooling system so the radiator neck hose will let fluid transfer to the radiator overflow bottle. When the engine is hot the overflow bottle should have a higher level of coolant in it. As the engine cools down after being shut off the coolant is drawn back up into the cooling system. If there is not enough coolant in the overflow bottle then you are pulling air into your cooling system and this is not good. This cooling system in the C4 depends on the fluid level being correct even in the overflow bottle as it is an integral part of the cooling system for the car.

This is why I replace the radiator cap, thermostat, anti-freeze and flush the cooling system every few years, I generally do it every five years at a minimum. I also take a good hard look at my hoses before I replenish the coolant. The littler overflow hose coming out of the radiator needs to be checked and replaced if bad. This hose is important as it is the one that helps keep the air out of your engine's cooling loop. The hose should transfer coolant to and from the radiator to the overflow bottle almost every time the car is driven so keeping the level at the correct height is critical.

If you hear boiling going on inside the engine that means the pressure is likely not there which would lead me to replace the radiator cap. With the C4's and their L98 engines they were known for running hotter than normal but it was done to clean up the emissions. But with just water they will boil away in a hurry, add a 16 pound radiator cap and the boiling point goes up to something like 260* instead of 212* and the cooling system works a lot better. Now add the proper amount of water/anti-freeze and the car is ready for action.

If your car is running this hot you should check the timing to be sure that it is set properly. The radiator cap might be faulty in your situation but they are inexpensive and easily replaced (When the engine and coolant is cool). If you keep the system full of coolant and have a good water pump then you should not have any more trouble.

I hope that this helps a bit! Cooling systems are now more important then ever as the amount of damage from one good overheating can exceed thousands of dollars in a modern car. If your questions have not been answered here try calling Tom at DeWitt's Radiator. Tom is the Master of cooling systems and I doubt you could find a finer source of information regarding your Corvette's Cooling system.

Best regards,
Chris

 

Do a pressure check of both cooling system and radiator cap.