Powertrain, generic · Fuel and air metering (injector circuit)

P0298 Engine Oil Over Temperature

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

P0298 is a protection code: engine oil temperature – from its own sensor, often combined with the oil level sensor, or modelled – has exceeded the protection limit. Saab's 3.0 diesel limits injection quantity when the oil stays at 135 °C or more for over 10 s, until it cools down; a heavy-duty bus engine warns in two stages and then derates. Ford stores the code without the warning light, in line with CARB's exemption for overheat protection. Usual causes are high load in heat, cooling problems, a clogged oil cooler or stuck oil thermostat, and occasionally a sensor reading too high.

Likely causes

High load in heat (trailer, mountain pass, stop-and-go)
Cooling or fan problem (clogged radiator, fan, thermostat, low coolant)
Oil cooler clogged or oil thermostat stuck
Oil temperature or level sensor reading too high
Low oil level or wrong oil

Symptoms

  • Reduced power, quantity limited
  • Oil temperature warning
  • Usually no check engine light

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–800
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

engine oil temperature sensoroil coolercooling system

Related codes

P0195P0196P0198P0217P0218P0520

References: law.cornell.edu, saabwisonline.com, static.nhtsa.gov, roushcleantech.com.