Post by
IanS »
https://forums.nicoclub.com/ians-u23642.html
Mon Dec 24, 2007 4:37 pm
Sludge in the radiator is almost always caused by petroleum mixing with antifreeze. Either you headgasket is blown and oil is passing into the cooling system, or one of your transmission cooler lines inside the radiator has failed. If you have a manual transmission, then you do not have a cooler, so the sludge is most likely caused by the headgasket. Does the car produce any white smoke? Overheating is often a sign of a bad head gasket.