Discolouration of Dexcool

[JHZR2]

thats the thing with dexcool... any little contaminant will do it.

Does the radiator have a radiator cap that is diagonal? If so, this tends to cause an air leak of some sort. Air is NOT good to be in contact with dexcool. Maybe there was a bit of air trapped, that, once it burped was 100% fine?

I think its always smart to replace coolant, if you havea chance. Id say to at least do the radiator, and swap with dex and distilled water.

JMH

 

[JohnBrowning]

You did not use any bar leaks of any pellets etc????? I added Bar Leaks to my coolant since I had done a lot of engine work and cleaned all the aluminum parts really well. My coolant was the green type instead of Dex Cool. It was nice and green until I added the Bars Leaks stuff. That stuff turned it brown quickly!

 

[Pablo]

When dexcool mixes with anything it turns dark. I'll bet there was some old coolant in the heater core, etc...

 

[George7941]

A year ago I flushed out the cooling system on a 97 GM van with 6.5l diesel engine and filled it with Havoline Dexcool and water 50/50. The very next day I noticed that the coolant had become significantly darker in colour. The old coolant had not turned dark and there has been no cooling system problems with the van which now has 350000kms (220000mi). At that time I did not know enough to use distilled water and I used tap water as I have always done. The water in Toronto is not hard at all, so I don't think it was dissolved minerals that caused the discolouration. But the water does have a lot of chlorine in it and I was wondering if the chlorine caused the discolouration. BTW the coolant is still in the truck a year later, it hasn't turned any darker. Should I leave the coolant in or replace it? I don't think there was any trapped air in the system since the coolant level in the surge tank has not gone down at all.

 

[George7941]

I did add two of the GM seal tabs because the GM shop manual recommends it. I have used these seal tabs elsewhere and I don't remember these discolouring the coolant.

 

[George7941]

There may very well have been some old coolant left in the system since I only flushed the system once. But the old coolant wasn't discoloured, so can bright new dexcool + bright old dexcool = dark mixture?

 

[TxGreaseMonkey]

I would suspect what Pablo said. Are any of your hoses, gaskets, or liner deteriorating internally? I've read that diesels are prone to pinhole leaks developing in their liners. Those tabs are to boost coolant protection, because of the unique needs of diesels.

 

[terminaldegree]

I'd probably flush it out again, and then get a coolant analysis if the discoloration starts to happen again. Or, you may wish to do that in the reverse order.

 

[OdinsRage]

quote:

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Originally posted by George7941:
I did add two of the GM seal tabs because the GM shop manual recommends it. I have used these seal tabs elsewhere and I don't remember these discolouring the coolant.

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oh man on my old caddies it would turn the green coolant BROWN!