# Mud in the radiator



## katea9tails

I am continuing to have dirt/mud forming around the cap on my radiator - my recovery jug is constantly empty. My indicator does not show the engine running hot but when I go to add the water back in I find the dirt forming mud around the rim - it is not rust - I was a tomboy I know mud. Is there a reason other than a hive of dirt doppers living in my engine?


----------



## bruiser

It is probably time to get the cooling system flushed. Then add new coolant.


----------



## Wrench97

Probably a head gasket leaking oil or combustion in to the cooling system, what brand/model car?


----------



## katea9tails

It is a 94 Dodge Caravan


----------



## Wrench97

V6 I'll bet, do you see any bubbles in the overflow tank when it's running?


----------



## katea9tails

yes with a 3.8 L engine - I will have to check on that cause everytime I check the recovery jug it is empty or near. I will have to check and get back to you on that.


----------



## bruiser

Seeing any white smoke out of the exhaust as you accelerate?


----------



## katea9tails

I checked and added water to the recovery jug - I watched and did not see any bubbles.


----------



## katea9tails

I have not seen any white smoke = since it is a van and I am usually alone in it - can't see the exhaust too easy but I would think I could see if it was smoking.


----------



## Wrench97

Do you see what looks like a B&W Milkshake on the bottom side of the oil cap?


----------



## SABL

Looks like it is time for a compression test. Not fun on a transverse mounted vehicle. I hate it when they turn the engine sideways!! 

Many good replies/questions posted by bruiser and wrench but I think we know that diagnostics are in order. The vehicle is 15yrs old and mileage is unknown. I have never owned that type of minivan and have no idea of the history of known issues. 

The level and condition of the oil would be nice to know. Translucent or brown/black is OK with black being favorable in the case of needing a long overdue oil change. Gray is never acceptable..... clear indication of water in the oil. Not all gasket failures will cause water contamination but can cause loss of coolant.

@kate..... I think bruiser and wrench can get to the bottom of your problem......you are in good hands.


----------



## SABL

Nothing important..... just getting away from current post #......eeks!!


----------



## woodson

may be dexcool instead of antifreeze and adding water to it makes it jell up


----------



## bruiser

Dodge doesn't use Dexcool. And water doesn't make Dexcool jell up.


----------



## AC DC

A rusty appearing substance (or mud as you call it) on the bottom of the radiator cap indaicates an internal engine leak in the cooling system. You need to pressure test the cooling system or you can assume you have an internal leak. A coolant leak can be extremely small and will not require that additional coolant be added for a long period of time. But the coolant will eventually leak out, depending on how large the leak is. 

I had a similar substance forming on the oil filler cap and the radiator cap on a Pontiac V8I ignored it and in about a week, it returned to normal. Apparently it was a head gasket leak between the cylinders and it was so small it resealed itself. 

A radiator shop or most auto repair shops will have the proper cooling system pressure testing equipment such a pressure testing kits made by Stant or Mityvac. They will remove the radiator cap and install an air hose adapter cap equipped with a pressure guage. Then the technician will pressurize the cooling system to a certain pressure and monitor the air pressure guage. If the air pressure begins to drop , the cooling system has a internal leak such as a blown head gasket or a cracked block or cracked head. In my past experience with racing engines, a small block Chevrolet V8 cylinder head has a nasty habit of cracking from the exhaust valve side of the combustion chamber to a 5/16" coolant passage hole that is located between the center cylinders.


----------

