Paccar MX-13 High Engine Oil Temp SPN 175 FMI 0

Question

My 2018 Kenworth T680 is throwing SPN 175 FMI 0 and derating while climbing grades with a heavy load. The oil temperature is climbing past 250 degrees while the coolant stays relatively stable around 205. I'm worried about cooking the bearings if I keep running it like this.

turbo_tony · Accepted Answer

The issue was a restricted oil cooler core and a sticking thermal valve. I replaced the entire oil module assembly (Part #2299215) and the oil temperature sensor. After swapping the module and performing a fresh oil and filter change, the oil temps now stay within 15 degrees of the coolant temp even on 6% grades. Total cost for parts was about $1,100 plus 5 hours of labor.

wrenchqueen · Answer

Hook up DAVIE or a diagnostic tool and monitor the delta between the coolant temp and oil temp. If the oil is spiking way faster than the coolant, it is almost certainly a restricted oil cooler or a bad bypass valve. Also, check the fan clutch engagement; sometimes the fan isn't pulling enough air even if it sounds like it is spinning.

Lina Brooks · Answer

You should check your oil thermostat (thermal valve) located in the oil module. If that valve fails to open, the oil bypasses the cooler and goes straight back into the galleries hot. It is a common failure point on the MX engines around 500k miles.

fleet_chief_42 · Answer

Check the wiring harness near the oil temperature sensor on the oil module. These harnesses can rub through and give a false high reading, though usually that triggers a different FMI for voltage out of range. If the temp is actually rising on a mechanical gauge, stick to the mechanical side.

Paccar MX-13 High Engine Oil Temp SPN 175 FMI 0

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