Either one is fine. People tend to shy away from Dex because pre-2000 Dex was involved in a class action lawsuit and GM lost (for destroying gaskets). It has since been re-formulated. I do not believe it is any better or worse then the green stuff.

The LIM gasket failures is because the nylon/plastic was crap. GM had problems as early as '94 (maybe earlier) in the 3100's (that never used Dex, they had good ol' green).

If you decide you want to go green, no issues. Try to do a full flush so your new coolant is not discolored by the previous Dex.

 

Thanks Maniac!

I'll use up the Dex I have around and then switch to green. My other vehicles (An inboard boat and a 1975 Suzuki "Water Buffalo" (1st water cooled motorcycle)) both use green. Then I only have to keep green around!

 

Get these while you're at it: APD-58176IQ Coolant Fittings/Tubes/Elbows For Intake Manifold To Belt Tensioner Upgraded Aluminum Design For GM 3800 3.8L Engine:Amazon:Automotive

You can find them cheaper, but that's just to show you what to look for.

 

Thanks Zipper! Actually I already did that upgrade a couple of years ago! My original plastic ones started leaking (5 or 6 years ago?) and I just popped new plastic ones in. When I saw some aluminum ones in my local NAPA store I grabbed them and when I had to replace the belt tensioner, I threw the plastic elbows away!

I'm expecting my new UIM today or tomorrow!

 

Update!

I finished my intake gaskets and new UIM! I'm probably imagining things but the engine seems to run/idle real smooth now! Today drained the tranny fluid and new filter. Thanks to all for your advice!

Tuesday driving from N.E. NC to Upstate NY and back (my dad's birthday on Halloween). 1300 miles round trip on a car with 202,000 miles so I wanted all this done before.

 

Ok, my UIM and all gaskets upgrade passed the big test! My trip from NE North Carolina to Rochester, NY and back went off without a hint of a problem. I guess I didn't screw it up. Over 203,000 now!