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**guyryan100** · 10-23-2022, 02:36 PM

Hi,
I ran my truck for the first time in several years yesterday. Its a crate stock 350 with < 500 miles on it. Yesterday I changed the oil, primed the oil pump, topped off coolant, and ran the engine for about 30 minutes, idling and test driving.

I have 2 issues and I'm not sure if they have the same cause.

Issue 1: Black sludge in the radiator. It is on the cap and everything I can reach with a finger is coated in it.

Issue 2: Black coolant leaking from the water pipe above the thermostat. This black coolant began leaking out almost immediately and at a steady stream. The clamp is very tight. It seemed like that pipe was under very high pressure and very hot, I noticed it almost immediately after startup.

The engine temp reached about 210 when idling. Initially I didn't have my electric fans connected, once I did the engine temp came down but still saw leaks in that location, always black water. But something seemed wrong to me on the cooling system even before I found the sludge. I even checked that my water pump is not running backward (its a stock pump, serpentine belt, turning counter clockwise).

Im sure I have oil in the water, I'm surprised to see a of of this sludge stuff since the engine is new. The oil I just put in was the first oil change. The previous oil had less than 500 miles on it. I saw no sludge in the radiator when I topped it off yesterday.

Also might be relevant, I have not set the timing except by ear. Its close enough that it ran smoothly and quietly but its not dialed in.

10-23-2022, 02:36 PM	#1
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 466	Sludge in coolant, high pressure Hi, I ran my truck for the first time in several years yesterday. Its a crate stock 350 with < 500 miles on it. Yesterday I changed the oil, primed the oil pump, topped off coolant, and ran the engine for about 30 minutes, idling and test driving. I have 2 issues and I'm not sure if they have the same cause. Issue 1: Black sludge in the radiator. It is on the cap and everything I can reach with a finger is coated in it. Issue 2: Black coolant leaking from the water pipe above the thermostat. This black coolant began leaking out almost immediately and at a steady stream. The clamp is very tight. It seemed like that pipe was under very high pressure and very hot, I noticed it almost immediately after startup. The engine temp reached about 210 when idling. Initially I didn't have my electric fans connected, once I did the engine temp came down but still saw leaks in that location, always black water. But something seemed wrong to me on the cooling system even before I found the sludge. I even checked that my water pump is not running backward (its a stock pump, serpentine belt, turning counter clockwise). Im sure I have oil in the water, I'm surprised to see a of of this sludge stuff since the engine is new. The oil I just put in was the first oil change. The previous oil had less than 500 miles on it. I saw no sludge in the radiator when I topped it off yesterday. Also might be relevant, I have not set the timing except by ear. Its close enough that it ran smoothly and quietly but its not dialed in.