Engine coolant temperature 199-203 but high engine oil temperature of 243

JIMMYHARTLEY

MEMBER
2009 FORD F-350
6.4L
V8
TURBO
4WD
230,000 MILES

I have a 2009 6.4 power stroke, with engine oil temp issues. Had a leaking oil cooler that went into coolant system. Flushed system good. Changed oil cooler, flushed again with Prestones flush/degreaser and temperature slowly climbs up to 243 but coolant stays at 199-203. I’ve re-flushed it four times. Both temperatures are right together at startup until coolant reaches its 199 mark, but oil keeps slowly climbing. Any ideas?

7 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon,

Are you using the correct weight oil? That is critical.

I would also use full synthetic oil as well.

Fluid Types

Engine Oil. Preferred Motorcraft Motor Oil 15W-40 Super Duty

Ford P/N. XO-15W40-QSD

Engine Oil. Motorcraft Motor Oil 10W-30 Super Duty

Ford P/N. XO10W30-QSD

Ford Specification. WSS-M2C171-E
Capacities

Engine Oil. 15.0 quarts (14.2 Liters)

NOTE: Includes 1 quart (1.0L) in oil filter.

Roy

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Thursday, December 20th, 2018 AT 9:46 AM

JIMMYHARTLEY

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4 POSTS

Not sure. I would assume. The shop changed it. That would make a big difference to bring the temperature down?

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Thursday, December 20th, 2018 AT 9:48 AM

ASEMASTER6371

MECHANIC
52,797 POSTS

Yes, the type and viscosity are critical to oil temperatures. A lot of shops do not know or care about it. They just put in any oil they have to maximize their profits.

Roy

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Thursday, December 20th, 2018 AT 10:05 AM

JIMMYHARTLEY