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I just bought a 2015 Mack CXU-613 heavy haul truck. During…

I just bought a 2015...
I just bought a 2015 Mack CXU-613 heavy haul truck. During the first week of operation (2,700 highway miles), the oil temperature has always stayed around 240-244F, while oil pressure gauge shows 45-50 PSI, and coolant temp gauge shows 170F almost all the time. The MPG stayed under 6 MPG (US) despite relatively light loads. Should I be concerned with high oil temps and poor fuel mileage; or is that normal for a brand new truck?
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Answered in 6 hours by:
11/10/2014
Technician: Wayne, Journeyman replied 8 years ago
Wayne
Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 17,977
Experience: worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling
Verified
Hi I'm Wayne
I will help you with this

Your engine is still breaking in,
your pressure and temps are good ,
try shifting before 150 RPM before governor speed this works on the cummins ISX
Wayne
Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 17,977
Experience: worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling
Verified
Wayne and 87 other Medium and Heavy Trucks Specialists are ready to help you
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Technician: Wayne, Journeyman replied 8 years ago
Thank you
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Customer reply replied 8 years ago

I don't understand the recommendation, 'shift 150 RPM below the governed speed'. This engine makes 1860 torque between 1150 and 1400 RPM, and maximum horse power of 505 between 1500 and 1700. That's what the manual and engine sticker say. There's no longer a fixed SINGLE number. Would you say the sweet spot of the engine can be half-way between Top Torque RPM (1400) and Top Horse Power RPM (1500), and that if I drive at 1450 RPM when loaded it might help with the fuel economy. Note: this is a MP8 505C+ 13 L engine rated for 1860 torque in ALL GEARS.

Technician: Wayne, Journeyman replied 8 years ago
Morning
Yes I did not phrase the correct
when I said 150 RPM, lower,
Yes sweet spot is around 1300 RPM
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Wayne
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Wayne, Journeyman
Category: Medium and Heavy Trucks
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