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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8954
Experience:  I am ASE Master Truck Certified.
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I have a CAT 3406E and I have been losing coolant recently.

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I have a CAT 3406E and I have been losing coolant recently. I have steam coming through the blow by tube. I cannot see any antifreeze or any leaks anywhere but I do have the steam coming through the blow by tube and losing coolant and can't figure out what's happening. The motor still seems to be running good. It doesn't appear that any coolant is getting into the crankcase. I am dumbfounded as to where the coolant may be going.
Thanks for asking your question. I will try and help you out.
If you are loosing coolant and steam is coming from the blow by tube. I would suspect coolant is in the crankcase. I see this often
There are several things that can cause this.
A water pump,
Head gasket
Cylinder liner
Cracked head.I like to drop the oil pan and pressurize the cooling system. You will see where it's leaking down and coming from.Please reply back if you need more help or have more questions. I am happy to assist.
Customer: replied 2 months ago.
If it's the water pump would that cause steam through the blow by tube? Wouldn't I notice coolant leaking through the water pump somehow?
it can. The water pump is gear driven. If the weep hole is plugged and the water pump seal fails. It will leak coolant into the crankcase.
If this is the case. You will see coolant falling from the front gear train with the oil pan off.
Customer: replied 2 months ago.
I would like to talk to you but not tonight as it's late and I'm very tired. I will contact you tomorrow. If coolant is getting into the crankcase should I be able to see it on the dipstick. It doesn't appear to be in the oil on the dipstick.
Sure no problem. We can talk tomorrow.
No normally you do not see any coolant on the dipstick.
Cat Man and other Medium and Heavy Trucks Specialists are ready to help you
Customer: replied 2 months ago.
Ok.. Thank you. I will be in touch tomorrow.
You are very welcome my friend. I am happy I could help.
Customer: replied 2 months ago.
Must be that you are not on line tonight. Sorry to have missed you. Hopefully we can connect another time. Thank you
You are very welcome my friend. I am happy I could help.