vortexas

Hi guys,

I have an 04 silverado 1500 ls based 5.3 motor. I am wondering if i can safely switch to green coolant after having had dexcool in the system for over 150,000 miles?

The radiator has been flushed several times with distilled water, so there is definitely no residual dexcool left in the system, however, im worried that since the cooling passages, water jackets, and heater core have been exposed to the special formulation of the dexcool chemical (proplyene glycol?) that introducing ethyl glycol (green stuff) will allow some type of caustic reaction to take place in the cooling system causing some crazy case of rust. (or any other strange thing i cant imagine)

Please let me know if anyone has successfully switched to dexcool after 100,000+ miles or, if that is a terrible idea.

Thanks,

Nissan LS240

iTrader: (1)

As a tech, I always say its best to go with what came with the car since you know theres no issues of corrosion or poor lubrication, seen some cars when doing head gaskets that have green coolant with lots of pits around the combustion chamber on the block, I don't work on too many ls motors just the one I have in my car and it only sees dexcool unless im at the track, then its just water and water wetter

ULTIMATEORANGESS

iTrader: (4)

couldnt those pits be from lack of change intervals or not flushing their cooling systems?

NowhereFast

Just put Dexcool back in it. The only reason it's looked down upon is becuase nobody changes it and it deteriorates. Otherwise, it's better than the green. If you maintain your vehicle, you will have zero problems.

t_raven

iTrader: (12)

Agreed.

There's a lot of myth out there about dexcool. FWIW My Silverado has 200k and my TA has 170k, both have had dexcool since new with no issues.

There's a lot more to coolant than just ethylene or propylene glycol, such as silicates, borates, phosphate, etc. It's pretty confusing and I wish I could find better info to explain it all lol.

Supposedly Dex can corrode older gaskets that weren't designed for it, but in your case, your engine was designed for it.

OEMs put a lot of research into this kind of stuff so just use what they call for. I use to be a Honda tech and I only put Honda coolant in a Honda. They changed theirs to blue back in '05. I only put Toyota coolant in Toyotas. They use 2 redish colors and mixing them with green makes it brown, I could mix it with dex but Idk if they are compatible. It's easy to just use what the OEM calls for and not worry about it.

Firebrian

I'd stay with the DexCool (OAT-PG) since you've had no issues with it. It might take a lot of flushing to remove all traces of it. And from the article below it suggests a specific chemical coating from the DexCool is now adhered to your coolant system. In any case I found the below article informative on various aspects of the 3 types of coolants available to us. It's from 2011 and written with Model T's in mind, but it's applicable to all of our cars. Seems to be a push for Red Line WW. A good primer on the use of coolants, how they work, what they do, and what they can't do.

http://rmaford.org/wp-content/blogs....uids_v2007.pdf

When it was time to change the coolant in my car, I stayed with the OEM DexCool just because it had worked fine for 13 years and I didn't want to take the risk that some of it might get left behind while switching to EG-IAT. You can probably safely change over as many others around here have done it.

RPM WS6

iTrader: (3)

This has been my exact experience.

I would stick with Dexcool for an LS application.