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Cat Man
Cat Man, Caterpillar Engine Expert
Category: Heavy Equipment
Satisfied Customers: 8854
Experience:  23 Years Caterpillar Engine experience.
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A c12 engine in a truck. losing coolant. nothing external.

Resolved Question:

a c12 engine in a truck. losing coolant. nothing external. not pressurising system. have renewed compressor head gaskets. been using for a while and now developed in to a serious job. bad engine knocking with flutter when reving. water coming out of breather
about to take heads off. any ideas
Submitted: 6 years ago.
Category: Heavy Equipment
Expert:  Cat Man replied 6 years ago.

Hi. Thanks for using JA! I will try and help you out.


I would recommend dropping the oil pan then pressurizing the cooling system. You may be able to pinpoint where the coolant is going.

Customer: replied 6 years ago.
cheers. good idea. vehicle has been in use for last 4 months. using 4 litres per day. coolant was not going into engine oil untill yesterday when engine knocking developed and thumb over breather and let go water sprays out . bad news. driver said oil pressure light came on a couple of times. checked pressure and 2 bar tick over. noise sounds piston. knocking clanking .
Expert:  Cat Man replied 6 years ago.
Thanks for the information.

That is a lot of coolant. I would be shocked if you don't see where the coolant is coming from. With that much coolant missing plus the engine knocking some, you may see the coolant coming out of one of the cylinders.
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