Coolant Looks like Sludge

May 16, 2006 Last reply: 20 years ago 3 Replies

I feel like I come here too often with questions and not answers. But here I am again... this time, my '94 F150 5.8 has a coolant leak somewhere. I can't track the leak very well to the source. The coolant is also not even close to green. It's sludgey and brown. I mean, how often do you have to change this stuff?! (Flushed & replaced new coolant last year in October) Is it possible something is leaking into the coolant? All the other fluid levels and colors look fine. I'm taking it to the shop tonight, just wanted any thoughts you all might have. Does coolant usually leave a horrible residue on your driveway that looks more like battery acid than anything else?



Mike W.



You've got oil in the water.

If the cooling is running through old dirty greasy grimy spots on your engine, that would cause it. You didn't say from what part of the engine you saw the coolant, but if it's a head gasket you might be leaking oil too.

Did you open the rad cap and look at the coolant to see if it has oil in it?

Does the truck have an automatic transmission? If so, it's possible that a transmission fluid cooler is built into the radiator. If the cooler is leaking and bleeding transmission fluid into the radiator it could cause the symptoms you're describing. Remove the radiator cap. If you find a strawberry/chocolate milkshake, it's a telltale sign.

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