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We have a 2007 Pete 379 With a C15 Acert, It was using too…

We have a 2007...

We have a 2007 Pete 379 With a C15 Acert, It was using too much oil so we had a in frame done it (had broken top rings on some cylinders i suppose someone used starting fluid to do that) after having the in frame it pressures up the cooling system under a load, temp is fine, but the driver says he has put as much as 4 gallon in it after a shift, it blows it out the overflow hose, pressure will remain on the system 4 hours after it has been shut off. We have changed the compressor and the problem remains.

Mechanic's Assistant: What is the complete model and serial number of your machine?

***************** 2007 379 engine MXS79630 C15 Acert.

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Answered in 3 minutes by:
12/2/2021
Technician: Nich1019, Cummins/Caterpillar Technician replied 10 months ago
Nich1019
Nich1019, Cummins/Caterpillar Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 2,881
Experience: Expert
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Hello and welcome to JustAnswer! I'm Nick and I'll be helping you out today. Unfortunately the answer to this question is that there is probably a leak at the head gasket or cylinder head. From here I would remove the oil pan and pressure test the cooling system. Leave pressure on the system for up to an hour or two if you don't see any leaks initially.  I'll be right back with more information.
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Customer reply replied 10 months ago
I will take it back to the shop that worked on it and have them pull the pan
Technician: Nich1019, Cummins/Caterpillar Technician replied 10 months ago

Inspect for coolant leaking from inside the cylinders when pressure testing the system. This would indicate a leak at the head gasket or a cracked head. More than likely the block will need to be machined if there's an issue here.

Ok sounds good. Also, I would ask if they tapped out the head bolt holes, that's something that's often overlooked on these engines but really should be done before installing the head.

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Technician: Nich1019, Cummins/Caterpillar Technician replied 10 months ago

Sorry for the bad news! If you have any follow-up questions just let me know.

Nich1019
Nich1019, Cummins/Caterpillar Technician
Category: Medium and Heavy Trucks
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