# I need a radiator flush



## Poncho Dan (Jun 30, 2009)

I popped the cap off of the radiator yesterday before going for a drive, and noticed this brown sludge on the bottom of the cap. I know its just got a hair less than 37,000 miles on it, and its only 4 years old, but sludge is unacceptable. If I get a flush kit, what size do I need, and what hoses do I splice it into? I'm assuming I refill it with Dexcool, right?


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## GTO JUDGE (May 14, 2005)

Sludge is unacceptable. However this is not sludge. This topic has been covered on here countless times.

That "sludge" is a sealer/rust inhibitor. Many mistake this for sludge and flush this out when in fact its purposely put there at factory to help aid in sealing any potential leaks, lubricating internal parts in the water pump etc, and keeping rust from building up. The Dex-Cool is a 150K mile coolant.

If you feel as though you must flush your radiator replace this "sludge" with a like product to help aid what was put there in the first place to help protect your radiator and internal workings.


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## fergyflyer (Apr 18, 2005)

DexCool is a good coolant when it's used in engines that were designed for DexCool. 

Most of the problems occur when one of a couple things happens. 

DexCool gets mixed with another type of coolant. There are chemical reactions that occur and bacteria also forms and it can destroy your engine. Always flush DexCool yourself, go to the dealer or a shop that is familiar with DexCool and takes the care to not use equipment to flush it that was used for other coolants. 

If DexCool gets into the wrong motor, the seals will fail. The GTO was designed for DexCool and has the correct seals. 

You should use distilled water, but that is true with any coolant, to refill. Metals in spring water and chemicals in the tap water aren't good for the system. Another reason to do it yourself. 

I believe GM says 150,000 miles or 10 years. From what I've read, I wouldn't trust DexCool past 5 years without regard to mileage. 

Small amounts of brown sludge are not bad, but like Judge says actually good. Large quantities indicate problems. I've read where people described the inside of their overflow resivoir as looking like it was lined with brown pudding,that's not good. Just seeing it on the bottom of the filler cap is good though, that means it's still lubricating. 

If for some reason you decide to go away from DexCool, fill the car with staright water. Run it and run the heater for a few minutes. Drain and repeat with water. Make sure you have flushed all the DexCool before putting other coolants in. You will save yourself a bunch of trouble down the road. 

A good replacement product is G-05 Zerex which is used by Chrysler, Mercedes and I think Ford. It is a good quality extended service coolant.


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## MJGTOWISH (Jun 15, 2006)

i thought it was 100k and every 6 years......... But As Dex-cool ages it turns acdic... I can't see a problem with changing it once a year..... The same with brake fuild, it is not hard or long....


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## Poncho Dan (Jun 30, 2009)

Cool, thanks for the answers guys. I do remember touching the stuff and it felt greasy. Whats the lubricant called? I've never heard of additives other than "stop leak."


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## GTO JUDGE (May 14, 2005)

Don't know what it's called but it's in the same line as stop leak.


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