Originally Posted by 1great40
I have had 2 long term experiences with Dexcool. The first is my 1996 Jimmy with 165K on it. Had been flushed many years ago (about 100K ago) and replaced with green stuff. Engine was perfectly clean inside cooling system. Engine had been opened once since because of a bad intake manifold gasket, original coolant re-installed. The 2nd one was my 2000 Sierra 4.8.. Water pump went at a little over 200K. The inside of that cooling system was as clean and the coolant was as clear as the day it went in 11 years before. I don't believe Dexcool to be a problem coolant and as stated the chemical design is also used in other coolants as well. The biggest problem you can have with coolant is opening the system up every year or so and messing with it. I know I'll get flamed for this but in the 45 years I have been building and repairing cars. I have never changed coolant on anything unless it diddn't have any to begin with...if it comes out to do some work, it goes back in.
Another observation is the GM intake manifold gasket leakage problem, which is universally attributed to Dexcool. I have never had a GM/Dexcool intake manifold repair job on a GM V8, the V 6's on the other hand...I've done plenty of them. My impression is that there is a gasket material/ torque spec/ thermal cycling issue on the V6 engines, in essence it's a design problem, not a coolant problem.
Before you wet your pants over the Dexcool, just run the stuff and when you do change it, use one of the newer "universal" antifreeze/coolants that are compatible with any coolant if you're worried, then the next coolant change you can move to an old fashioned ethylene glycol coolant if you feel more confident using it.
My bet is the car will be long gone to that big swapmeet in the sky before you have a problem related to any coolant.
You dont do many 1996-2000 Vortec L30/305 or L31/350 intake manifold gaskets?
These trucks are the 1996-2002 GEN-1E Vortec engine design. The intake gaskets have a bad design, but as you state, Dexcool is often blamed.
These 96-99 4.3/305/350 fullsize trucks also have that cheap heater fitting that comes out of teh intake manifold and supplies the heater core with coolant. Its a Quick Connect fitting that is made of cheap pot metal and breaks off if you look at it wrong. Dorman makes a great replacement. But even better, simply cut off the QC fitting and screw a conventional brass or other material pipe threaded collant nipple into the intake manifold and use a gear clamp to hold the heater hose on. I notice better heater performance when this is done.
You 1999+ LR4 4.8 engine is a GEN 3 engine design, it is much better design.