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Proper Coolant for a 1992 GMC K1500??

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This truck is new to me and it needs the cooling system flushed and the coolant replaced.  The owner's manual calls for coolant that meet "GM Specification 6038-M".  That spec is no longer supported and it NLA.  After some research, I thought I was doing the right thing by getting...


Prestone Antifreeze/Coolant GM Vehicles Dex-Cool CONCENTRATE *5 Year/150K Mile Protection* 1 Gallon (Part # AF888) which I plan to dilute, of course.  But, upon seeing the jug, it says it is orange and specified for '95 and later GM models.  I am on the wrong track?  If so, what should I be using?


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What is in it now? Orange or green? You can use any coolant. It came with DexCool. If anyone put green coolant in it you can still use DexCool style coolant but then requires flushing more often. Frankly though, you are over thinking it. Just use that Prestone you showed.

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The problem with Dex in older models has been the intake gaskets or other gaskets that come in contact with the coolant. Prior to gasket redesign, the gaskets failed from the Dex eating away at them thus causing leaks internal to the engine.


If all the gaskets have been replaced and it's currently running Dex, use it. If it still was running with the "green", I'd put that back in it.



Edited by txab
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Thanks for the input everyone.  It's currently running the traditional green stuff.  I hadn't thought about the potential gasket issues brought up by @txab.  That's a good catch.  I think I will stick with running the old green stuff.  From what I've read, I think GM Spec 6038-M is a low silicate version of green.  I will look for something like that.  It's weird that the orange Prestone Dex-cool I bought said it was an exact fit for my vehicle, but the jug says otherwise. 

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