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Coolant tank full of thick brown

Ralph195

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2016
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195 G
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There is thick Brown substance in my coolant tank that seems to be oil based. But my oil level is OK and not contaminated with coolant.
Does anyone know what this could be?
Thanks
 

Scarab 215

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I'm no expert..

Do you have a brown tint to the coolant color, or is it more like sludge?

How many hours on your engine?

Possible rust / corrosion?

Possible oil in the coolant, however you said oil is not contaminated.

Not certain the recommended intervals / time frame for flushing the coolant system?

Has the system been flushed to your knowledge, possible wrong coolant / mixed different coolants together?

Are you able to share a photo?
 

geierb387

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Another idea, may be a mix of incompatible coolants? When GM originally changed to Dex cool there were similar issues. Food for thought, if that's the case it will make a nice gooey mess and will need addressed.
 

Ralph195

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Than you Scarab 215 and geierb387 for your replies.

Thanks geierb387 you set my mind at peace a bit with your reply, I was talking to friends that told me that it could be a head gasket or a crack in the engine block. I think if it was a head gasket or a crack in the engine block the engine would be running rough and my engine is running perfect....
Any other comments would be greatly appreciated.
 

Winerocks

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Sounds for sure like oil in the coolant. It doesn’t take much to turn it into beige mud/sludge. If it was a cracked block, you’d likely see the beige crap on the dipstick. With a bad head gasket, it can push oil into the coolant, depending on which part of the gasket failed. It would be good to check your spark plugs, which can help diagnose the issue. A bad head gasket can allow some coolant into the combustion chamber while the engine is not running. This can cause corrosion, and visible damage to the plug. When the engine is running, there is enough pressure in the combustion chamber to push oil/unburnt gas in the other direction, turning the coolant beige. Not sure where else it could be coming from.
 
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