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I’ll use a 50/50 premix from ACDelco, as the concentrate isn’t available here. But I suppose that shouldn’t be a big deal, right? I only drive the car in temperatures above 0°C (or 32°F).
Hi, I’m about to “refresh” the coolant - i.e., drain the old coolant through the radiator petcock and refill with fresh ACDelco Dex-Cool premix (50/50). Just to double-check: will 2 gallons of fresh fluid be enough? It should be, but I want to be sure since getting ACDelco premix isn’t as easy here in Europe as just visiting an AutoZone around the corner.
I also did a simple pH test, and the current coolant isn’t acidic yet, which is why I’m only doing this partial refresh.
Also, I plan to do this with the car on the ground, as lifting my C7 - even with a low-profile jack - is a bit of a pain in my garage. So I won’t be removing any splash shields from underneath. Just to be prepared and avoid making a mess on the garage floor or in the engine bay - where does the coolant actually flow once the petcock valve is opened?
Thanks!
Refer to my earlier posts 13 and 14. A simple drain and refill requires nearly 7 qt of premixed coolant. Those two 1-gallon jugs equals 8 qt in USA units. Yes that should be enough.
The pet **** is at the driver side bottom of the radiator facing inward toward the engine compartment. You can reach it from above but you will need a large enough drain pan 8L or larger to catch the drainage. Be sure to have the expansion tank Fill cap open first to allow it to drain together with the radiator.
I’ll use a 50/50 premix from ACDelco, as the concentrate isn’t available here. But I suppose that shouldn’t be a big deal, right? I only drive the car in temperatures above 0°C (or 32°F).
You will be fine with 50/50 mix as Europe ambients are not as hot as the SW USA. The actual GM spec for C7 and C8 vettes is 60% water / 40% ethylene glycol actually which provides less freeze protection but greater heat transport per unit of coolant mass flow than 50/50. JMHO as a career long heavy rotating machinery engineer dealing with their associated lubrication and cooling systems.
Thanks for the confirmation and clarification, much appreciated! OK, I’ll do it over the weekend. Mainly, I just wanted to check that without removing any splash panels or covers from underneath, the coolant won’t end up spilling all over the place.
I did mine in garage, 2015 ZO6, It took a few minutes to find petcock. Drained fluid, flushed w garden hose till clear, then filled with garden hose water and brought up to temp and Drained. Filled twice with distilled water and brought up to temp and drained. Then filled with 40% dexcool and distilled water. After driving added bout 1/2 quart distilled water. I did put car on jack stands all 4 corners so my bucket could be used
George_L: Thank you so much for the link and for documenting the procedure - much appreciated! Thanks to it, I noticed that there’s actually a drain hole under the petcock, which made draining the old coolant a fairly clean job.
I wasn’t aware of that before, and I had watched a YouTube video where the guy removed some splash shields prior to draining the coolant. That left me a bit puzzled and also made me expect a much messier job, since I wasn’t planning to remove those.
Anyway, I drained about 6.5 L (i.e., 6.9 qt) of old coolant and added about 6 qt of new coolant. This afternoon, I’ll start the engine, let it warm up, top off the coolant, and take the car for a spin.
My 2016 Corvette still has the original coolant. I checked with a couple independent shops. They wanted about $200 plus the cost of coolant to do a flush and refill. Our local dealer charges $250 for the entire drain, flush and refill. I have an appointment next week to get that done as well as the brake fluid replaced and brake system bleeding.
My 2016 Corvette still has the original coolant. I checked with a couple independent shops. They wanted about $200 plus the cost of coolant to do a flush and refill. Our local dealer charges $250 for the entire drain, flush and refill. I have an appointment next week to get that done as well as the brake fluid replaced and brake system bleeding.
Vendor selection by cost isn't a good idea. I realize service facilities dumb it down for most people but it is a good idea to see what you are paying for by the flat rate hours. There is a number of hours they are billing you for. With that, I can see if you are cutting short the time to give me a better number. People here were thrilled they got the triple flush for half the cost but it wasn't possible to do the job as prescribed for what they're paying. Long story short, they got a pan drop instead of the triple pan drop.
One more thing though - when I was topping off the coolant this morning, I noticed there are no “cold fill” or min/max markings on the coolant expansion tank. I even grabbed a strong flashlight to double-check the lower transparent section of the tank, but still found nothing (see picture):
I also checked the service manual linked by George_L, and from what I can tell, it’s not very specific either:
Slowly fill the surge tank (1) with a 40/60 coolant mixture until the coolant level reaches the base of the surge tank fill neck. Refer to Approximate Fluid Capacities on page 1-37.
Note: Monitor the surge tank coolant level closely. The surge tank coolant level will begin to decrease once the engine is started.
Start the engine and allow the engine to idle. Allow the engine to idle for approximately 4 minutes.
Slowly fill the coolant mixture until the level stabilizes at the base of the surge tank fill neck.
Run the engine between 2,000–2,500 RPM for approximately 2 minutes.
Allow the engine to idle and add approximately 1 liter (1.1 quarts) of coolant to the surge tank.
Install the coolant pressure cap.
Shut the engine OFF.
Allow the engine to cool.
Top off the coolant as necessary.
So basically, it says:
Top it off to the base of the surge tank fill neck.
Let the engine idle and add approximately 1 liter (1.1 quarts) of coolant to the surge tank.
The issue is, I ended up having to take the car for a short drive, then let it sit overnight and cool down - and only then did the coolant level actually drop. I also didn’t really want to just guess on that extra 1 liter.
So… what is the correct coolant level when cold?
Should it be somewhere around the middle of the transparent section of the surge tank?
The full cold line is about where the black and cream color seam is or just a bit lower. There are arrows pointing up but hard to see. Look at front of reservoir with good flashlight.
I’ll use a 50/50 premix from ACDelco, as the concentrate isn’t available here. But I suppose that shouldn’t be a big deal, right? I only drive the car in temperatures above 0°C (or 32°F).
I took my 2016 Zo6 into the dealer for a coolant exchange and they used the 50/50 premix AC Delco coolant. However, the owners manual calls for a 40/60% Dex-Cool to 60% distilled water. I understand this provides better heat transfer which is important for the supercharged LT4 during aggressive driving. What's everyone's opinion regarding leaving it at 50/50 or should I make an issue regarding the 40/60% ratio?
I have thought about removing 2.95 quarts of coolant and replacing it with 2.95 quarts of distilled water to obtain the 40/60% mixture. Or having the dealership correct this since issue I paid $280 for the service.
I took my 2016 Zo6 into the dealer for a coolant exchange and they used the 50/50 premix AC Delco coolant. However, the owners manual calls for a 40/60% Dex-Cool to 60% distilled water. I understand this provides better heat transfer which is important for the supercharged LT4 during aggressive driving. What's everyone's opinion regarding leaving it at 50/50 or should I make an issue regarding the 40/60% ratio?
I have thought about removing 2.95 quarts of coolant and replacing it with 2.95 quarts of distilled water to obtain the 40/60% mixture. Or having the dealership correct this since issue I paid $280 for the service.
Thoughts?
Assuming you want to change it, Having the dealer redo it is a royal PITA. You have to bring it there and all that, assuming the argument is successful. In PRINCIPLE, I would do it. OTOH, if it is as simple as draining 3 quarts out, is the "Juice worth the Squeeze"?
Yes, I am going today to buy a cheap hydrometer and test the coolant to see where it actually stands before draining etc.. According to Grok AI a 40/60 mixture should test out to -18F while the 50/50 mix protects all the way down to -34F.
I used a separate 1 gallon jug, put 51oz ish coolant in it, the rest regular bottled drinking water, repeat, until it's full. Took it for a drive till fully warmed up, cool it down, fill again. I didn't do this, wonder once it's drained, if anybody turns the engine over just a bit to get more fluid out.
-18F is pretty good. The only exception would be, if you lived way up north and kept your car outside.
I used a separate 1 gallon jug, put 51oz ish coolant in it, the rest regular bottled drinking water, repeat, until it's full. Took it for a drive till fully warmed up, cool it down, fill again. I didn't do this, wonder once it's drained, if anybody turns the engine over just a bit to get more fluid out.
-18F is pretty good. The only exception would be, if you lived way up north and kept your car outside.
The owners manual actually addresses that fact. If you live in a colder climate the 50/50 mixture if fine, but in hotter climates the higher water ratio is superior for heat transfer.
I just watched a YouTube video in which they are flushing the coolant from a 2015 Stingray and the guy jacks up the rear and says that will help to drain out more coolant. Does anybody think that is going to help any? He says this at the 3:30 mark.
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