1996 F-150 4X4 5.0 Liter S/C overheats after driving in stop and go traffic. The coolant starts pumping out of the jug. Water is rusty and will not flush clean, and the radiator takes forever to drain out of the drain plug. Seems to have lot of sludge build up in the bottom of the radiator. Has anyone experienced this problem, and if so, what did you do to get yours back to normal?

 

mine wasnt overheating...but took many flushes to get clean. i mixed white vinegar and water and ran it on that for several weeks....flushing and refilling about once a week. it eventually came clean..

 

Coolant coming out is not "overheating" - it's just "coolant coming out". The caption of this diagram explains how the coolant system works and what commonly goes wrong with it:


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If you can't flush the radiator clean (it takes a LONG time when the coolant has been neglected), replace it.


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If the radiator cap fails a pressure test, or if you can't test it, replace it with a Stant or MotorCraft.


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Thank you, I'll try the pull and flush technique to blow out the sludge.