hi,

check this, on HVAC control panel, put on off, press temp up & down at same time during 5 seconds, push auto until 16 is selected. you will see in celcius degres cooling liquid temp based on EMC information. in Celcius temp should be between 95 to 105°. if temperature stay in this range, thats just means your gauge temperature sensor is end of life.
It was the case on my 90's vette

 

I would still recommend that if you want to "Clean" the radiator you should try the Coil Cleaner used by AC mechanics to clean the coils in your Home AC system. I use it on my condenser and my radiator as well. It removes most of the corrosion on the aluminum fins and leaves it sparkly clean when done. You simply spray it on, brush it IF you have to and then rinse with a garden hose with no adapter on the end of it. You want to use little to no pressure cleaning the Coil Cleaner off the Corvette when done. It CAN damage paint if it is left on it too long.

Being a part-time welder I also have "Aluminum Cleaner" from my welding supply shop. It too will remove almost All of the corrosion in one application. I used it to make aluminum look nice and shiny on my Cessna 172 as well. I think it is a bit stronger than the Coil Cleaner but it is very effective.

Last but not least, don't use TOO MUCH anti-freeze in your coolant mixture. I use 30% anti-freeze to 70% distilled water and it transfers the heat very effectively. The higher the concentration of Anti-freeze only helps you in the Cold months. In the hotter places you want to run even more Distilled water if you have to. I have seen people with their Car overheating due to the 100% anti-freeze in their coolant.

Your water pump needs some lubrication to prevent prematurely wearing out the seal in it. Anti-freeze has the lubricants you need but you don't need 50% or more anti-freeze unless it goes below 0* (F) regularly where you live. Here in Northern Virginia we don't have the same temperature range as Wisconsin or Utah, it is Hot, Humid and rarely goes below 0* here. I have seen it do it once in over forty years here.

A surfactant is very useful in warmer climates. It disperses the layer of bubbles that form on the inside of the cooling jacket deep inside the engine and allows the coolant to transfer heat more efficiently and effectively. It is known by the name, Redline Products gave it "Water Wetter". It is cheap and it really does help.

Like others here on the Forum I acknowledge that GM did a great job designing the C4 and it's cooling system. The Cooling System is able to keep the engine comfortable in many adverse situations. The key to a good running Corvette is to do the maintenance that the C4's require. I replace the coolant about every five years and the radiator cap and thermostat every ten. The hoses I watch and at the slightest sign I will replace them as well.

Probably the One item that has a to be watched for is the overflow bottle and it's connecting hose. If the overflow jar is not working then you are going to have air inside your radiator and that will make the engine run hotter potentially. Check the hose and verify that the heated coolant is indeed able to get into the overflow jar. If not the hose might have a crack or hole in it or you have a bad radiator cap. After shut down mark the coolant level in the overflow jar and then let the engine cool down. As it cools down it should draw the coolant back into the radiator and replace what was expelled due to expansion

 

Not true. The water pump has a sealed bearing. That bearing has grease in it. The grease is what lubricates that bearing....not the coolant. The water pump does not need any kind of "Lubricant".



Coolant should be replaced annually, unless you're running Ext Life Coolant, in which case it is then, every 5 years. If you change regular coolant every 5 years, you'll likely get crud build up w/in your cooling system and also experience heater core failure.

 

I don't drive the Corvette enough to change it every five years. Currently I have the dash out and am planning on yanking the heater core out and replacing it BEFORE it breaks and forces me to do the the job right THEN. I hope this is worth it but after reading all the stories here on the Forum I think it is a wise decision. I flush all my cars to prevent problems and keep the cooling system working its best. I was and have been told by many service writers that I waste money doing the more frequent flushes.

In my younger years I remember driving out in the drier areas of east Africa and using an "Egg" to seal up the Water pump seal that was leaking our coolant away and the service stations were few. and far apart. We got back to civilization all in one piece.
They told me, "don't pressurize the system or it will pop right out". With a Hot leaky engine all you do is add an egg to your radiator and let it circulate. It will clog up at the leak and seal as it cooks the egg white. That won't help any old Sealed bearing... I don't think I would re-use the radiator without a complete cleaning.

This "sealed" bearing on a water pump is "new to me", I have advised to be safe to always have some kind of lubrication in the cooling systems. Folks who run 100% water in place of an anti-freeze coolant need to use something to help the water pump I was taught. I must be getting old or something.

 

IDK. People like to make up problems for themselves to "solve"....all the time. Like parking tires on carpet squares for the winter, as one example. Then they pass that crap on to others. "Water pumps need lubrication".

But think about this: If automotive engines' water pumps need lubrication to prevent seal failure.....(ready for this?)....how do boat's pumps survive??? [/brain explode]
Boats with I/O's and inboards use car engines. Those engines use typical car water pumps on them to circulate raw water (in most cases) from the lake, through the engine. Not only do they NOT have any "lubrication" other than raw water, but they also frequently have to deal with silt, sand and other debris going through them. Yet they survive. No lubrication.

Same for race cars; they're not allowed coolant b/c coolant on a track is slick and hard to clean up. So, race cars "suffer" along with straight water.

My own Mastercraft is 30 years old and has 1050 hours of use on it....original, Ford water pump on the 351...and it's never been lubricated by anything other than lake H20. How can that be?