Crumley

Alright...i have a problem with my cooling system I can't seem to figure out in my 94 civic...the car isn't overheating or anything, but in my overflow tank almost every time i check it occasionly it is empty...inside of it seems to contain some kind of carbon build un the edges of the container and a dark substance is in the bottom of it. The fan doesn't seem to be coming on, but i have changed the fan switch, the engine coolant temperature sensor, the radiatior is still under warranty, and if i straight wire the fan straight to the battery it comes on. Im sick of thinking, does anyone have any clue?

De_tour

Could be oil from a bad headgasket, check your oil in the motor to see if it looks milky.

JarvisW

Yep, and like I said in the other thread, watch the fluid in the radiator, if it 'fizzes' when you rev the engine, then its a bad gasket or warped head.

Good luck!

Crumley

Sorry it took me so long to send back and i appreciate the help...i forgot to add this...i had another motor in it about 10k miles ago, its the same D15 but this one just has 100K on it. my other motor ended up blowing, but it had the same problem that this one has and i changed out the head gasket and almost everything in the whole cooling system with in 45,000 miles i had that motor, so im thinkin its not that, but ill check the oil tomorrow just in case.