I just picked up my first Vette from a forum member a few weeks ago. Its an 06 z51 3lt coupe. Has 12500 miles now and today I changed: plugs (wires were in great condition) all the fluids: brake, diff, tranny, coolant (didnt fuss with figuring out how to drain the clutch, so syphoned the cluch reservoir, refilled, closed and pumped the clutch 20 times, and repeated that process till the reservior was just new amsoil dot 4 (blue) brake fluid). Everything went smooth and all fluids were in good shape (minus the engine oil being a bit black).

only issue of concern was the coolant. antifreeze was predominantly green..it had orange in it but def not 100% dex/distilled h2o. wondering what issues this can cause? Why/how reg antifreeze wouldve been used i am not sure!!

I found a post from Kid_Again in another thread (post was from 12-05-2002, 08:00 AM)
Frequently Asked Questions:
Can DEXCOOL organic acid antifreeze be mixed with ethylene glycol antifreeze?
It is ethylene glycol based antifreeze! The concern with mixing comes from the fact that there are very different chemical inhibitor packages in use. Most leading technologies will work very well when used as intended, typically at 50% in good quality water. If the coolants become mixed with DEXCOOL, however, one study showed a possible aluminum corrosion problem in certain situations. The other question is a concern for dilution of the protection packages. At what mix is the there too little of either inhibitor to protect the engine? As a precaution, both GM and Caterpillar instruct that contaminated systems must be maintained as if they contained only conventional coolant.

what to do with an obviously contaminated system. i refilled today using factory recommendations (dexcool). should i flush again? refill using conventional (assuming that means old skewl green). thanks all...

 

I would just flush again, fill it with the right stuff and be done with it.

 

Your engine was filled at the factory with Dexcool. Therefore its corrosion inhibitor had an oportunity to coat and protect your engine before some dizz head put green coolant in. THOROUGHLY flush the system and refill with Dexcool and it should be OK.

 

Thx guys. Spoke to prev owner who said he topped off with green .. Prob within the past 6 months or so. Debating another flush to be sure its all out.

 

I wasn't sure if you had already flushed or not. There is a difference between Dexcool and regular green antifreeze, but it is not a difference that causes damage. It only reduces the change interval, not the effectiveness of the antifreeze. If you got most of the green out, I would leave the new orange in there and then just flush again in a few years, a little earlier than you would if there had never been any green at all.

"According to the DEX-COOL manufacturer, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch's change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."

Remember that this is "mixing"...which is different than just having a little bit of leftover green in the system.

 

thanks guys. appreciate the feedback. I will prob flush it again in the coming weeks for peace of mind. temps look good as do fluid levels.