2003 5700 coolant

[beach146]

I have an 03 5700 in my boat. It is coolant cooled, and the manufacturer recommends dexcool. Right now there is green coolant in there. I don't know if its original green coolant, or something like prestone's green universal coolant where it is similar to dexcool.

 

I read somewhere that once you use green coolant in an engine, then it is not worth switching back to dexcool since you cannot get all the green out and therefore the dexcool would not last any longer.

 

I also read that dexcool caused problems in early vehicles, but I can't find if the problems were fixed by 03.

 

Is there any specific flush chemicals that would let me switch back to dexcool? Or is there another recommended coolant?

 

I know this is a GM truck forum, but I figured this would be the best place to ask a question about vortec 5700s and dexcool.

 

Thanks for any help!

[Chris]

To switch back to dexcool tou have to do a flush. Sypposed to use distilled water but I just use the hose

 

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[Jsdirt]

The hell with Dexcool. Save your money and run the green stuff. Just my .02 ...

[beach146]

I thought I read that normally a flush doesn't get all the old coolant out.

 

I was kinda leaning towards using green coolant.

 

 

Which dexcool safe green coolant do most people use?

[Chris]

It takes a few times. You flush til clean water is coming out

 

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[Wolfmanjohn]

It's worth the effort; a 50/50 mix of dexcool has better heat exchange properties than a 50/50 mix of the green stuff.

[Carder09]

It wasn't necessarily Dexcool that caused problems, it was the cheap ass gaskets that were incompatible with Dexcool that they were using. It is a very good product that lasts hell of a lot longer than the green stuff. You might want to just stay with the green stuff unless you want to change. But your year motor might have the "cheap" gaskets so take a chance if you want.

[Badass69]

Its not gaskets that were incompatible with the coolant...... the coolant had zip and zero to do with the 4.3/5.0 and 5.7 intake gasket failures. If he had crappy intake gaskets they probably would have let go by now.... especially with the heat and load a boat puts on the engine. The original gaskets are junk plastic with rubber impregnation around the ports to seal. The portion of the gasket that fails isn't due to coolant..... hell it doesn't really touch the coolant. The plastic gets deformed over time and warp/tears the rubber seal.... voila.... coolant mess everywhere. The 3.1/3.4 and 3.8 V6's had the exact same problem..... it's the cheap shitty GM gasket. GM even admitted it by now making some of the nicest "problem solver" manifold gaskets you can buy. Put an aluminum or steel gasket with the rubber in place..... run whatever coolant forever and never have a leak.

 

If it has green just dump it and fill it with green as it's not worth the hassle to switch it to Dex Cool. I like Dex myself and use it in everything but really it's no big deal to use the green stuff...... it worked forever before and still does well today.

[beach146]

Its not gaskets that were incompatible with the coolant...... the coolant had zip and zero to do with the 4.3/5.0 and 5.7 intake gasket failures. If he had crappy intake gaskets they probably would have let go by now.... especially with the heat and load a boat puts on the engine. The original gaskets are junk plastic with rubber impregnation around the ports to seal. The portion of the gasket that fails isn't due to coolant..... hell it doesn't really touch the coolant. The plastic gets deformed over time and warp/tears the rubber seal.... voila.... coolant mess everywhere. The 3.1/3.4 and 3.8 V6's had the exact same problem..... it's the cheap shitty GM gasket. GM even admitted it by now making some of the nicest "problem solver" manifold gaskets you can buy. Put an aluminum or steel gasket with the rubber in place..... run whatever coolant forever and never have a leak.

 

If it has green just dump it and fill it with green as it's not worth the hassle to switch it to Dex Cool. I like Dex myself and use it in everything but really it's no big deal to use the green stuff...... it worked forever before and still does well today.

That was great information. My only problem is that I don't know if its conventional green antifreeze, or if it's a universal green antifreeze(like prestone), which tend to be pretty much dexcool. I think I'm going to flush and switch to dexcool.

 

Thanks again!

[Chris]

Just keep flushing until clean water comes out