Stay with Dex-Cool or switch?

[nthach]

I'll be doing an LIM gaskets on a 1997 Chevy Tahoe that was originally filled with Dex-Cool and there's sludge when I alerted the person driving it his coolant was low. I know GM had issues and it's common knowledge that it's not Dex-Cool in itself that's bad but rather the OEM cooling system design with the gaskets and radiator cap. My plan of attack is to flush the cooling system with citric acid and a detergent, change the LIM/UIM gaskets over to Fel-Pro's improved design, change the t-stat and install a Stant 10230 cap with a spring-loaded center.

For coolant, I want to keep it Dex-Cool or a Dex-Clone(Prestone or SuperTech) - it's easier to get and this truck is serviced by a quick lube, which also means they use an AMAM Dex-Clone. Or should I switch it over to conventional green or G-05, which I think both will work but I'm worried about potential contamination if the owner or someone else pours the wrong coolant in.

 

[440Magnum]

For later GM applications I always say stick with Dexcool. But given an early Dex application with a known LIM problem already, I'd go G-05. Its one of the closest things to a universal coolant, but I respect the manufacturer in that they never push it as such.

 

[Sayjac]

Seems like you sorta answered your own question. Want to use Dex or clone, going to be serviced at a quick lube, they mostly use dexclones to top off, so Dex seems right here to me. You're using the improved gaskets so that shouldn't be a 2eha issue again.

That said, if you do switch to G05 make sure you get all the old Dex and don't let the quick lube top off the AF after.

 

[ArrestMeRedZ]

I've got a '97 C2500 with the 5.7. I meticulously followed servicing instructions. It still developed leaking LIM gaskets. I replaced them with factory gaskets (original or improved, don't know). Refilled with Dexcool, and ran for about a year before I became aware of the Dexcool/gasket incompatibly problem. Another good flush, and changed out coolant to G-05.


Never had a sludge problem with Dexcool, even though the system developed a couple of leaks that were subsequently taken care of (not Dexcool related).

Even if the LIMs were the improved factory or Felpro Problem Solvers, I would still go with G-05. My rationale is there are other gaskets in the system that could be damaged by repeated long term contact with Dexcool. Plus, with the non-pressurized overflow system, even though I didn't have the problem, enough people have had sludge to know it is a real concern with Dex. I'd use G-05 and put a big warning on the overflow tank to indicate "Only service with distilled water and Zerex G-05 coolant, or catastrophic cooling system failure may result!".

 

[barkingspider]

I went with supertech dexclone after LIM gasket replaced (improved felpro) on my old 02 S10. Zero problems. I would go with cheap dex clone on that 97

 

[cptbarkey]

2000 chevy 2500 6.0, replaced the radiator and it now has universal peak antifreeze. it is the color of golden barf. its not dex cool, and has worked fine.

 

[nthach]

I got the LIM in, but I didn't have time to flush the system - I will in 2 weeks. I topped off with AMAM, and we're going to acid flush and refill with clean coolant ASAP.

Whoever did the initial gasket replacement used the cheaper nylon/silicone Fel-Pros and overtorqued them + glooped RTV all over them.

 

[TiredTrucker]

I fill all my GM vehicles with the same stuff I put in my Detroit Diesel.... Peak Global Final Charge ELC coolant. It is the red stuff. No SCA's, no nitrites, no silicates, no phosphates, no borates. OAT coolant with 1 million mile / 8 yr service life. I change it sooner than that though, even on my heavy commercial stuff. I emailed back and forth with the tech guys at Peak about using it as my standard coolant for all my motors. They were quite clear that it would work fine throughout all platforms and brands, wet sleeved or not. It has CAT, Cummins, MB, MAN, Deere, Paccar, Volvo approvals.

http://images.peakauto.com/Final Charge Red_Spec Sheet_hires.pdf