CAT D6C Coolant Leak

[1974FJ]

Ive got a D6C10K that has a coolant leak. its not a visible coolant leak that i have identified. my fear is its loosing coolant inside the motor via cracked head or leaking head gasket.
is there a good way to find out?

 

[Dave Neubert]

are you building pressure in the radiator is coolant blowing out the over flow. crank up the dozer let it run a minute remove radiator cap is there any pressure. check your breather and dip stick any sign of moisture

 

[kshansen]

Another option would be to take an oil sample and have it run through the tests, might find all kinds of things. One thing to keep in mind is the real value in doing samples is to spot trends and not just a one time test.

If you do pull the sample and get it tested might be good to post results here as I'm sure there are many who can tell much from the results.

 

[Coaldust]

Pull the engine oil drain plug momentarily and look for coolant in the basement.

Sometimes the weep hole on the water pump leaks and the koolaid evaporates before it’s able to be detected.

Just a couple quick checks.

 

[kshansen]

Pull the engine oil drain plug momentarily and look for coolant in the basement.

Sometimes the weep hole on the water pump leaks and the koolaid evaporates before it’s able to be detected.

Just a couple quick checks.

And sometimes that weep hole can get plugged by insects and a leaking water seal on the pump will force coolant past oil seal. Never understood why they did not position those weep holes so you could view them easy and keep them clean!

 

[Vetech63]

And sometimes that weep hole can get plugged by insects and a leaking water seal on the pump will force coolant past oil seal. Never understood why they did not position those weep holes so you could view them easy and keep them clean!

Cause engineers never think we have to actually repair things they design.

 

[1974FJ]

are you building pressure in the radiator is coolant blowing out the over flow. crank up the dozer let it run a minute remove radiator cap is there any pressure. check your breather and dip stick any sign of moisture

I’ll try this, I believe there is a large screw on cap that has a rubber tight seal and then there is a standard looking radiator cap that would relieve pressure if there was any.

 

[1974FJ]

Pull the engine oil drain plug momentarily and look for coolant in the basement.

Sometimes the weep hole on the water pump leaks and the koolaid evaporates before it’s able to be detected.

Just a couple quick checks.

just crack the drain plug, water would leak first if it had any?

not familiar with the weep hole. Where is the weep hole located?

 

[Coaldust]

 

[Coaldust]

The water pump weep hole on your engine is hard to see, maybe a mirror could help. I spent some time trying to find a picture. The parts diagram doesn’t show it. It’s even harder to try and explain the location. But, if it’s leaking you will see it or the stain from the coolant.

 

[kshansen]

Couple thoughts or observations on the weep hole.
1. If mud wasps or other bugs have managed to fill that hole you will not see any external leakage. I had just that problem on a 3306 in a Cat loader. Was able to use a wire or welding rod to poke at the weep hole and then it showed externally

2. Another time I had a coolant leak into the oil and spent several hours trying to determine the source of leak. Pulled valve covers and oil pan looking for leaks while pressurizing the cooling system to about 15 psi. Never saw a single drip! Went home and came back in morning to a large puddle of coolant on floor. Turned out that the water pump seal only leaked after the pressure was removed from system!

Keep in mind that on an engine like the D6C there are other possible sources of leaks. Might be the engine oil cooler, the head gasket, the liner lower seals and also a hole in the liners themselves.