techvette

My cooling system could use a good flush. A few questions:

Where are the engine block drain plugs located?

My car is a 1996 and has what appears to be Dex-Cool in it. At least it is red...There have been many complaints about Dex-Cool in the past.

I would be using the red coolant equivalent to Dex-Cool sold in the parts store (Prestone, etc.) Is it a good idea to use this or should I flush the system and run normal green coolant?

IRAraid

The drain plugs are in the lower block, just above the oil pan, about mid-engine front to back. Each side has a knock sensor screwed into the drain hole. Remove the wire from the knock sensor by squeezing the connector. When squeezed correctly, the wire will come off very easily. There are two 'shields' and when they are removed, there's a lot more room to work.
When you pull the knock sensors, there's going to be a flood. If not, use a screw driver to poke the corrosion loose. I use a kids sand box cover to catch the coolant. It's about 4' in diameter and gets most of the splash.
There's a lot of 'discussion' regarding the red vs. green coolant. I'd stick with the red.
After draining and flushing (the service manual recommends water flush only - no chemicals), refill with antifreeze and coolant. Let the air out with the ONE purge valve (on '95 and '96) and catch any liquid with a towel to keep it off of the opti-spark distributor.
When filling, running, etc. shut the engine off if the analog gauge approaches 260. After filling, the service manual recommends against 'aggressive maneuvers' until the temperature has been fully cycled from cool to hot at least 3 times. During this 'air purge' cycling, you will observer wider than normal temperature fluctuations. Yea, takes a good 3 days.
This is long but hope it helps.
Good luck

scorp508

Might not hurt to overfill the expansion tank just a little so it'll suck in fluid instead of air when cooling down.

LT1CORVETTE

Great write up IRA.
Stick with Dexcool.

Time allowing. I would highly recommend removing your surge tank and rinsing it out really well.

samsonb

Where do you guys put the jack stands at? I have an 89. I've been told to put the jack under the center of the K member, but haven't seen it mentioned where to put the stands at. Don't want it to crush me.

theadmiral94

DO NOT use 'green', would also recommend DO NOT use Prestone. Suggest going to dealer and buying their 'dex cool' and only using it.

Reason is there are subtle differences in the chemical composition and with all the problems with Dex-Cool, you want to make sure it's the exact same chemicals.

Also, suggest only using distilled water and after 'flushing', add pure distilled water, run it to hot, and drain it again, -- also a shop-vac on blow-mode will help remove additional stuff, and on suck-mode can be used to clean the black 'surge' tank and the 'overflow' tank without the need for removal.

Lastly, its a perfect opportunity to replace the thermostat (should always be replaced when doing anti-freeze anyway) -- suggest only using ACDelco brand thermostat (might be # 131-100).

MK 82

Only if you like wasting money. If it says Dex Cool on the jug, it is just as good and surely cheaper than the same thing from the dealer.

scorp508

Look on the frame rails and you'll see little triangles \/ that mark the jack points. The front too are sort of under the front part of the door jam and the rears are a few inches forward of the wheel well.

samsonb

Yeah, I know about those. But I had read alot to not use those, only in a roadside emergency.

Though, in the past, a shop has jacked it up wrong as the back of the floorpans are dented.

Strick

Last I heard was that there is an ongoing class action suit against Dexcool. Apparently it causes problems. Lets be honest here, I don't see any difference material wise between your 96 and my 92 which would require only dexcool in yours and green stuff in mine. In the past it was taboo to mix dex with green as you got a mixture similar to sludge. But now they have antifreeze that mixes with both. A thorough flushing should allow you to go in either direction, but I'd go with the extended life antifreeze that can be mixed with either or any antifreeze.

samsonb

Last I heard, that antifreeze that can be mixed with whatever is a Dexcool clone. Like Prestone. I use Zerex as you know what you are getting.

Strick

When I did mine 2 years ago, I stayed with the green stuff, Prestone. It wasn't this new stuff that you mix with everything.