Radiator Cap

I have a brown sludge on my radiator cap, what can it be?

rust rust rusty:) just give him a pipe and put it back on to start worrying when the water is brown

I do not know some newer cars about those that I have a 1963 Chevrolet
in his pipe and into the engine and the radiator has a metal spring in the pipe to prevent it from collapsing under the pressure that seams to rust a lot:) just look for it!

James-

Engine oil. Get a compression test done on the engine ASAP. You have a head gasket leaking oil back into your cooling system. If you check your oil filler cap, you can find milk "choclate / caramel" colored sludge inside the ceiling too. You can also check your gauge and see if the oil has a milky appearance too.

This should not be that bad of a problem if you fix it before it gets worse. Gasket replacement should run less tha $ 500.00 if you do not have a machine work done to the head. Then, Get Real expensive very quickly.

..... Well

How is your coolant level? How is your oil? How's your compression? And what color is your exhaust system?

All these questions are probably something you should look into because you have a leaky head gasket. Oil and coolant mixes and running back in your coolant reservoir.

Have head checked and replaced.

The slug is tan and water. Get the radiator flushed. Fill with distilled water and antifreeze.
Why not tap and distilled. There are no minerals in distilled water.

Looks like someone added to stop the leak in the vehicle at some point in the past. Some corrosion may also occur on the CAP, if the cooling system is not serviced at regular intervals.

Sludge Brown is the engine oil, you have a head gasket
problem, or someone pores of oil in the radiator

If you mix antifreeze types of red and green, it turns brown it could be that you need to rinse or it could be a problem head

rust in your cooling system, cooling system flushed complete.

I agree with wrench8. It could be as simple as stopping the leak. If the coolant itself seems to thick mud, then look further.

rusty brown sludge is mixed with water