Is Dexcool Really That Bad?

[JGmazda]

Thanks for all the input! The issue I am having is with the LIM gaskets on the GM 3.4L As I mentioned in my original post, we had the engine out & replaced stuff just to replace it. The water jacket part of that gasket was soft & squishy, ready to fail. This after only 30,000 miles. Is there a direct relationship with the dexcool usage & this gasket failing? Always have used quality parts. The gasket that was in was the new improved GM item. I think we used FelPro this time, hope it lasts. I'm switching to the OG green Zerex, but still have to flush all the old crap out. Never had an issue with sludge, just the gasket failing. You can see weeping from that gasket if you can get a good view of it.

Edit: The Dexcool I was using was Havoline (the brand actually mentioned in the owners manual), I bought a 6 gallon case from Zorro a few years (5) back, & they are apparently famous for selling old stuff. Is it possible I got a batch of the old formula? It was not able to be shipped to CA, not sure why, but I think it didn't have the bittering agent that is now required.

Since I changed all the gaskets on my 3800 engine, I did a complete flush and use PEAK 10X in all my cars. I can't say the DEX is a bad coolant, it's just not the only kid on the block now. I like "simple". Using one coolant in all my vehicles makes my life a bit more "Simple". PEAK 10X is a great coolant and I'm sure the "Green" you are thinking about will work just fine.

 

[bullwinkle]

I have 2 Fords that use Motorcraft orange Same as Dexcool. I haven't had any problems. Must be a GM thing. LOL

On the big Transits, something with flux welded heater cores. We only had one plug partially, still had heat on one side? Not mine, back flushing fixed it.

 

[dogememe]

On the big Transits, something with flux welded heater cores. We only had one plug partially, still had heat on one side? Not mine, back flushing fixed it.

Was this a widespread issue? I heard a bit about it. But wondering if it was really the coolant or bad heater cores?

 

[bullwinkle]

My 2000 Montana's transmission failed, so we rebuilt it, & while the engine was out, we replaced everything likely to have issues. One of those issues is the infamous 3.4 intake manifold gasket which is prone to leaking coolant into the crankcase. The gaskets were soft & spongy at the coolant passage, getting ready to leak. These gaskets had been replaced 3.75 years & 30,000 miles ago. Used nothing but the factory recommended Dexcool 60/40 ratio.

I went to buy coolant, now everything on the shelf is "long life, use with any color coolant". I wanted the old style green coolant, but got the Prestone any color coolant which happens to be a green-yellowish color. Good thing, because there was Dexcool left in the engine, we only emptied the radiator (which we replaced) & rear heater core.

I watched the video by Flat Rate Master saying Dexcool is not bad, but GM put it in cars that had old style gaskets, & the acid in dexcool ate them up. Is the acid what's softening up my intake gaskets? These gaskets are supposedly the updated steel backed version, but they were still soft. I also read on here that Dexcool was reformulated a few years back, did that solve the issues? Flat Rate says the acid in Dexcool is what keeps the cooling system clean, & Dexcool does not mix well with air. My expansion reservoir is open to the atmosphere, so it's getting air.

Any thoughts? I'll post a link to the video mentioned.

The issue is air in the radiator, and the block, causing corrosion & sludge. Between GM’s worthless plastic radiator caps & nylon LIM gaskets, leaks galore occurred. Then air caused corrosion in the block, incorrect green IAT coolant was added, stopped up messes resulted. Or, like my indy mechanic’s parts runner/ loaner S-10 4.3: a massive coolant dump into the crankcase caused spun rod bearings & thrown rods almost instantly, without warning. Still wonder how much Dex had to do with GM’s bankruptcy!

 

[hank2]

There had been a quiet reformulation of GM Dexcool at one point. The issues subsided to some extent after that. One major point was to have a totally air free cooling system.

 

[JohnnyG]

I would advise against using the "OG Green" coolant in modern engines. The 2HEA technology was developed for a reason. I have also read that water pump seals will not last when silicates are introduced into the engine. Whether that is due to the seal material currently used or not, I have no idea.
Probably too late for this advice. To make matters worse, once the green stuff is put into the engine, no amout of flushing will remave the silicates.

 

[JGmazda]

I use PEAK 10X in my Buick. (Former DexCool)..... According to their website, it's free of silicates.

(Quoted from the website)

PEAK® Antifreeze + Coolant is formulated for use in all vehicle Makes and Models and is specially engineered to deliver guaranteed superior lifetime protection*. Its advanced universal formula contains a proprietary blend of 10X more scale-fighting inhibitors† coupled with robust organic additives to fight against the damaging effects of scale deposits and corrosion. PEAK® Antifreeze + Coolant is free of 2-EHA, silicate, nitrite, borate, and amines, ensuring maximum cooling system performance for 10+ years/300,000+ miles*. It is compatible for use with any color or type of antifreeze + coolant in the system.

 

[JGmazda]

Plus... If this hot chick uses it...It MUST be good.

https://www.owi.com/retail/diy-hub/faqs-%26-education

 

[Plawan]

Plus... If this hot chick uses it...It MUST be good.

View attachment 177810

https://www.owi.com/retail/diy-hub/faqs-%26-education

Who told her she could leave the kitchen!