1999 Suburban 5.7 flush and fill

[STL_G8GT]

So I'm doing intake gaskets on a 1999 5.7 vortec in a suburban. It's got an active leak, and best I can tell, there is GREEN in the system right now. There's a jug in the back of the truck of generic green, and the drips aren't orange.

For a flush and fill I'm willing to start fresh. The one big caveat here is that this vehicle stays in florida year-round but is only driven November - March. I'd rather not put in a coolant that I need to change in 3 years - because that won't be much driving at all between the time-induced changes.

So I'm looking for a long-life coolant that would be safe for this old truck and avoid the corrosion issues found on the intake surfaces.

Current contenders are Peak Global Lifetime, Titanium, & Zerex G05.

I see what used to be Peak 10x is now 10+, and lists potassium and sodium 2-EH. With the way the rtv is used to seal various parts of this engine (including my new intake gaskets at each end and joints, I believe I want to avoid any 2-EH, especially with long periods of sitting between running.

I read the thread above about the guy in Alaska - and I thought to start a new thread because I'm not limited in near on hand quantity - I'm ok ordering this product from amazon or any of the local napa, orielly, autozone, or advanced auto.

 

[slacktide_bitog]

Both PGL and Titanium will be fine in your Suburban

 

[dogememe]

Why not just go back to Dex-cool?

 

[slacktide_bitog]

Why not just go back to Dex-cool?

Deathcool is what causes the problems in the first place

 

[dogememe]

Deathcool is what causes the problems in the first place

From my understanding, the problem was a combination of the original formulation of Dex-cool and bad original parts.

Dex-cool has supposedly been reformulated since then, and there are better gaskets available now. Why not use it?

 

[JHZR2]

Deathcool is what causes the problems in the first place

It can have problems if the radiator cap is wrong, the system leaks and runs low, silicate antifreeze is added, etc.

At this point if you think the green is green, not some AMAM dex clone, you’re probably best off going G-05. Or something else besides dex.

If you could make the system pristine, with a citric acid flush, trusted all your gaskets, etc., going back to dex is an option. Going to another OAT without 2-EHA is also an option perhaps if you don’t know the history of all gaskets.

I still run dexcool in my 1998 4.3L.

 

[STL_G8GT]

I'm fairly confident that the green is green. This guy didn't exactly maintain the vehicle well, but I don't see a mix of colors, and the "spare" jug in the back is run of the mill universal green.

I certainly don't know the history of the gaskets

 

[JHZR2]

I'm fairly confident that the green is green. This guy didn't exactly maintain the vehicle well, but I don't see a mix of colors, and the "spare" jug in the back is run of the mill universal green.

I certainly don't know the history of the gaskets

Then I’d probably drain the radiator, add distilled water, run to hot… cool down. Drain the radiator and the block, fill with distilled, run to hot. Cool down and drain. Repeat. Then drain both and fill with G-05. There are many other options and variants but I’ve always found that approach to work well.

 

[ArrestMeRedZ]

With my '97 C2500 5.7 Vortec, I replaced the leaking lower intake manifold gaskets with dealer supplied parts (don't know if they were original design or improved) at about the 7 year point. Refilled with Dexcool. Then I became aware of the Dex/gasket incompatibility and immediately flushed and switched to G05. Never had another problem for the next 18 years.
Based upon a sample size of one, I vote for Zerex G05.

 

[STL_G8GT]

Thanks all - drained block / radiator and got just under 2 gallons out. Replaced with distilled water. Will drive it for a bit, then drain again. Then again. Then G05. It was easy to get locally.