tealex

Is the recovery tank the only place to refill the system or is there another filler cap on the top of the radiator under the plastic cowlings. Don't want to take them off if I don't have to. I want to replace the coolant before the winter, it will be 5 years old. Thanks

BadAV

I can't answer your question, but I just did a flush/fill on mine today through the overflow. It was a piece of cake, and the petcock on the lower passenger side came loose easily.

Cockroach

Change antifreeze????? my DD is 16 years old with over 240k and I have never changed the antifreeze..... it is a Mercedes though. lol

C6ToGo

This is the procedure from another member that I used:

Buy 2 gals Prestone Dex Cool (Walmart) and 6 gals distilled water. I used 5 gals of distilled water this year
and flushed it twice. I think three flushes would have been better.

1) Drain coolant (drain plug is on passenger side). Approx. 8 qts out of 12.6 qts will actually drain.
2) Pull Surge Tank and clean out crud. Refill surge tank to the neck with distilled water.
3) Start engine, idle 4 min
4) Top off surge tank
5) Rev engine at 2000-2500 rpm for 2 more min. (temp should reach ~200 F)
6) Shutoff engine, cool for 20 minutes
7) Repeat steps 1-6 until fluid drains clear (2-4 flushes)
8) Refill with 6.3 qts Dex Cool (it's a slow process) and then top off with distilled water.
9) Repeat steps 3-5, take test drive, refill as necessary with distilled water.
10) Dispose of your old antifreeze at a recycling center.

BlindSpot

This is a good process and one that I use with ONE ADDED piece. I would rewrite step #3 to say:

Start engine, set heater setting on HIGH (Temp high, not fan high, both sides).......

It is more efficient and better flush to keep the heater temp set on high through to the end of step #9, as it opens the coolant path through to the heater core. Does two things:

1. Provides a better flush of entire system
2. Less likely to have a trapped air pocket in the system.

Turbo6TA

C6ToGo posted a very good procedure for flushing and refilling your coolant.

To answer your question about radiator caps ... The Corvette does not have a conventional style of metal 'radiator cap' mounted directly on the radiator, like most other cars have. The only place to fill the system is the black plastic cap on top of the coolant surge tank (recovery tank).

Turbo6TA

BTW .... Since your C6 is only 5 years old (must be a 2012), and maybe a fairly low mileage car, you may not need to remove the surge tank to clean it (as long as there is no visable crud in it).

BadAV

Mine was clean.

Not So Fast

All good advice, but don't be in a hurry cause it aint happening refilling it is a slow process and I flushed 4 times before it came out clear. Took around 3 hours for me
Good luck
NSF

Turbo6TA

Same for me.

BTW ... After you are all done, check the coolant level everyday for a few days. As the system slowly burps out air, you may need to add to the surge tank a couple of time before it finally stabilizes in it's coolant level.

z06clif

I had mine done at the Dealership and I watched Him use this tool thats a big box on rollers . Its hooked up to the car and a process is followed. The new anti freeze is placed in a visible holder on the top and the process starts . The car is flushed and brought up to temps and when its ready the machine draws the new stuff in. I watched it be drawn into tthe system. The machine is under pressure insuring no air bubbles are in the system. . Pretty cool
On the funny side....what if this is a dealership ploy and everything is phoney and the machine is designed just to make noise and have the anti freeze go up and down. Lmao

Clif

Cherokee Nation

My 2008 tank was very clean also when i changed my coolant 2 years ago,there should be no crud in the tank.

cmonkey713

You need to "Burp" the system to get all the air out as outlined in steps 3 to 5.

ErikR

I can add nothing to the discussion.... except pictures...

https://www.corvetteforum.com/how-to...adiator-368427

montman

I would not use distilled water. It has a low pH and there is a lot of debate about it causing corrosion. If you're buying Prestone, get the Dexcool 50/50. This is made by the factory with the correct pH. If you use the GM stuff, it specifically says to dilute with drinking tap water - no mention of distilled. Highest regards, Monte

RobLo

Had mine done at the local dealer by their Vette mechanic who does side work after hours, he's got some kind of deal with his boss. Anyway, I stood there and watched him do the exact same thing after he changed all my hoses, thermostat and water pump. He used that pump to fill it up using exactly the right amount of GM coolant and water then pressure tested the system afterwards...all was and still is good!

Turbo6TA

Here is my problem with buying the pre-mix Prestone Dex Cool that is already at a 50/50 mix of coolant and water:

After you are done flushing out the system with clean water 3 or 4 times, and now you have no visable sign of any of the old coolant coming out ... there will still be a good amount of clean water in the system (you can't get it all out after all your flushing is done).

If you now add the 50/50 pre-mixed Dex Cool, you will end up with a lot less than the ideal 50% Dex Cool, due to all the water that still remained in the system after you finished flushing.
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However, if after you flush the system 3 or 4 times until clean ... and then add 1 1/2 gallons of the full strength Dex Cool, and then add water until the system is full ... you will in fact have the correct 50% / 50% mix of water and Dex Cool.

As per the owners manual of my 2011 GS. it says that the coolant system holds exactly 11.9 quarts of liquid. So a 50% / 50% mix would be 6 quarts (1 1/2 gallons) of full-strength Dex Cool added to water until the system is full.

The only way the pre-mix 50 / 50 Dex Cool would work is if you could somehow drain every drop of water out of the system first ... which is impossible if the system isn't drained from engine block drain plugs.
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And yes ... The owners manual of my 2011 GS says: "Use a 50/50 mixture of clean, drinkable water and use only DEX-COOL Coolant".

.

jaredtxrx

Unless it is snowing outside you don't need a 50/50 mix. I've seen plenty of guys (granted these are guys that are tracking their cars) go to 10% coolant. Water is a better cooler than the actual chemical coolant.

Turbo6TA

I partially agree with you.

Pure water, as you may know, has a boiling point of 212°F at standard atmospheric pressure ... However, a 50/50 mixture using water and ethylene glycol (coolant), the boiling point rises to 223°F at standard atmospheric pressure.

Of course, these boiling point temps go up much higher in a pressurized cooling system.
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However, your right too ... Pure Water has a lower viscosity than coolant, so it transfers heat better than coolant (good).... but, on the other hand, Pure Water boils at a lower temp than coolant (bad).

Take your pick

.

z06clif

Nesenger 112?

Clif