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2007 Mack granite blowby & major oil leak


WaldoMack

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I have a 2007 Mack granite quad axle dump truck with a MP7. Bought it from its original owner. Truck runs solid with 390k on it, no loss of power. Oil pressure holds around 40/idle 60-70/driving but major blow by & oil leak from the blow by tube(literally puddles under blowby tube after it warms up & leaves a steady drip trail while driving) & getting worse!! Going thru about 3 gallons a day between leak & oil burning!!! Ordered a inframe kit from PAI. Hopefully that solves my issue. Has anyone seen anything like this before?

Edited by WaldoMack
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We've actually got a truck with an MP7 in the shop puking blowby. Long story short, it needs an engine due to crank scoring and no/low compression in two cylinders. Cranks in MP series engines are not meant to removed according to our service team.

Short story long: In typical dealership fashion, we chased low oil pressure faults first for some reason and not the massive amount of blowby coming out the breather. The tech was angry when he found out they were wasting his time. Found the crank scored and bearings trashed, but the customer's tech came out and said to just roll new bearings in. Didn't magically stop the blowby though. 

To actually try to answer your question, it could be time for an in-frame, but I'd listen to Joey first and look into the CCV before you go ripping the engine apart. Other than that, we've seen a bad air compressor charge the crankcase to the point where it appeared as blowby. Long story short for that, we installed two different engines by the time the truck left our lot. Yes, it was an absolute mess. 

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