ok i have a 1990 nissan 240.it keeps over heating but no leaking and oil that looks like mud is coming out of my intakebox.is that were all of my coolent is goin..can anyone give me a heads up.....thanx

 

you might have a blown head gasket.

 

yeah check for a blown headgasket...one way you can do it is to use a block tester from an auto parts store. It's a small liquid filled cylinder with a rubber cone you stick into the radiator neck. Start the engine and make sure the coolant level is low so that you don't suck any coolant into the cylinder. Use the air pump to suck air from the radiator thru the liquid...if it changes color...it means combustion gases are leaking into your cooling system from the head gasket....good luck