I'm getting ready to drain my antifreeze and clean out the deadspace between the radiator and condenser and I am looking for recomendations for what type of coolant to put in the corvette.....

In other cars I have used Prestone, but didn't know if the Corvette would need something different........

 

I use Prestone coolant in my L98. If you have a LT1 you'll need to buy Dex-cool antifreeze.

I just noticed you have an '86. Get the green Prestone antifreeze. A bottle of Redline watter wetter wouldn't hurt either. :cheers:


[Modified by NUckINg FuTS, 3:58 PM 5/26/2002]

 

It's best to use what came with the car. 86 came with green (Prestone GREEN will due just fine). 50/50 mix is stock, you could go to 60 water / 40 green for more cooling, but remember the coolant is there for corrosion protection too. I run 60% distilled water / 40 green. Dionized water a little better if you can find it.

DexCool was not used in Corvette's until 96 AFAIK. So most LT1's use green, last year used Orange.

 

Peter. I am about ready to flush mine and would like to know what ratio did you use to get your 60/40. I want to run that with some water wetter

 

Mine holds about 14 quarts with the heater core included. So I wanted about 8 and 1/2 quarts of Distilled water to 5 1/2 quarts of Coolant. But it's never that easy, it's very easy to end up with too little coolant with a full flush, here is why:

To flush properly you want to drain all the coolant, and replace with new coolant. But you can never get all the old out, in fact it's hard to get more then about 80% out. So you have to flush. I flushed the heater core, block and radiator the best I could with a hose and tap water (yuk). [Aux oil cooler is a great spot to get lots of the low lying coolant out].

But I did not want tap water in my block, so when I was sure I got all the coolant flushed I could get I filled the block with distilled water and ran to operating temperature, packing the system as usual. Then cooled and drained; it came out greenish. Repeat and repeat again until clean. All with heater running.

Now drain like in the beginning, except no flush as I wanted the distilled water, not tap water in there. It came out fairly clean, but still some small amount of green. Good enough. Should really pull the freeze plugs and clean the water jacket behind there, but too lazy at this point.

I then filled with a pre-mixed store bought Texaco 50/50 with distilled water and green AF. Filled the system with this mix and ran up to temp with the cap removed, and packed the system when hot. BTW I filled in the heater hose, in the gooseneck (where thermostat goes) and finally in the radiator.

After driving for about 15 minutes at temperature I let it cool. I knew it should be below 60/40 but how to test? I used a hydrometer and the mix was at about -10* F freeze protection. That is about 60/40 as I calculate. So I did get most of the distilled H2O out of the system.

To the extent you leave old coolant in the system, corrosion protection and lubricants (for water pump seals) are reduced. If you leave too much of the flush water in the system, the mix is reduced and the same applies as above. Best method is full flush and hydrometer test. If you end up with too little AF in the mix, drain a little and add pure coolant.

I also replaced the thermostate, pressure cap, and about 3/4 of the hoses while doing this. It seemed like the right time to get this done. I did all the "hard" hoses as they looked orginal. Also found that Gates / Goodyear hoses don't fit all that well and had to use GM for the lower hose after wasting money on both - which did not fit even with trimming.

Side comment:

If you have replaced any cooling system component like a heater core or radiator, you should get an aftermarket add-in to boost the silicant levels in the coolant. The silicants are the main corrosion protection additive in green and will "plate out" on to new metallic surfaces leaving you with insufficient protection on the new parts. Don't think WW will suffice for this purpose. Prestone and others make a "boost" product that is meant for this application, make sure it says to add suplimental silicates.

Sorry went on so long.

Pete

[edit] Dang, I must be an engineer. You asked me what time it was and I posted how to build a clock.


[Modified by PeteL, 7:25 PM 5/26/2002]

 

Thanks for the info. That is what I was going to do but was hoping you had some magic way to get the 60/40

 

GM has a nifty machine that they use for DexCool to make absolutlely sure they get the proper 50/50 mix. It goes in line under operating conditions and totally flushes the coolant. Input mix is whatever you supply. This is the magic, but can't afford such a fancy machine for my driveway! Good float hydrometer (getting harder to find now-a -days) is cheap, and fairly accurate when you use the temperature compensation supplied.

I bought one of those Prestone coolant testers, and it is not even close - or repeatable. I'm using an old float hydometer I bought in the 60's. Looking for a new one as I wonder how long these things are accurate.

I may just use test strips, which seem to be very accurate. See: http://www.acustrip.com
Think that is the correct link.