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Bad oil cooler?

4K views 34 replies 9 participants last post by  R&Rpowerstroke 
#1 ·
I have a 2005 6.0 that some days the deltas get 30+ apart and other days it never gets past 10 degrees apart. My coolant never hits 150 and my oil is usually always in the 170's. I know it's probably my oil cooler but could it be anything else like my thermostat?
 
#3 ·
I run my truck with the egr delete and studded. Just out in a new oil cooler a year ago.. I don't have it tuned or lifted. I always change the oil at 3000 miles and I run cat coolant. With a coolant filter. I am just driving on the highway about 55 miles an hour. Same road same speed everyday same time.
 
#4 ·
Your numbers right? My ect is between 188 and 205, eot is between 190 and 210. That is operating temp no towing with outside temp between 70-100. Right now it is cooler so they are closer to 188-194 ect and 194-199 eot operating temp. This is an 03 that is tuned, studded, deleted, but stock sticks, stock tire size.
 
#6 ·
150 is too low. Check your ECT/EOT before starting after an overnight sit. They should be no more than a couple degrees difference.

-jokester
 
#9 ·
What I'm trying to say is that your coolant temperature sensor might be kaput. Check ECT and EOT on a cold soak and if they aren't within a couple degrees of each other, start checking coolant temp sensor wires and possibly replace the sensor.

And yes, if they match and no issues are found, you might have a thermostat stuck open.

It's easier to check the sensor readings first and go from there.

-jokester
 
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#8 ·
I wonder if your thermostat is stuck open?
 
#13 ·
How long are you driving the truck before you see those temps?

-jokester
 
#15 ·
Check your sensors on a cold soak the next chance you get and make note of them. You need to drive farther than that to check your deltas! Take it for a 30 minute drive at 65MPH and then re-check your temps. It doesn't sound like your getting the truck up to temp yet. When checking the deltas, anything below fully operating temps are irrelevant. 30 minutes at 65MPH should be sufficient.

-jokester
 
#16 ·
I'm saying my truck is 40 apart after ten minutes of driving. That's ten minutes out of the 45 minute drive I do everyday. Once I get 30 minutes into my drive the wrench light comes on. I just put a new thermostat and new sensor in. Now my coolant is 170-178 and my oil is 190-210 depending how far I drive. So I'm thinking I need to back flush my oil cooler..
 
#17 ·
178F still isn't operating temperature. You need to get the coolant to 190F anything below that and the test is irrelevant.

Proper testing

Coolant Minimum temp 190F

Maintain 1900 RPMs for 15minutes (for 3.73 gears its 65 MPH) (or until delta stops growing or has already exceeded 15F)

Take note of oil and coolant temp if it's less than 15F apart you're fine.
 
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#19 ·
While I do think your oil cooler is probably plugged, it still has me wondering why your coolant temp only gets to 180...

You said you changed the coolant sensor, right? Did you check the readings on a cold soak before, or just straight up change the sensor? OEM sensor?

-jokester
 
#22 ·
You still need to get your coolant temperature up. How cold is it where you're at? Is the fan always on? Did you check the cold soak temperature to see if they are the same?
 
#24 ·
202* EOT is not too hot after an hour at 70 mph, like everyone else said your coolant isn't up to temp. What code do you get when it throws the wrench? Do you hear your fan running?
 
#25 ·
The code just says the deltas are off too much. And no I havent had my fan kick on in a long while. But I literally have replaced everything within 10k miles such as
New fan clutch
New fan
Oil cooler
Radiator
And I run cat rated coolant with a coolant filter.
I have had the coolant filter on since I bought the truck. And every time I Cut one open it's clean as can be..
 
#26 ·
OEM oil cooler?
 
#27 ·
How would non OEM oil cooler bring his coolant down?


To OP do you have access to a temperature gun? If so use it on the thermostat housing and see if it matches the Edge. Only thing I can think of since it's not freezing cold where you're at is the thermostat you got was bad out of the box.
 
#28 ·
A non-OEM oil cooler wouldn't bring the coolant temp down but it could take the oil temp up. Two separate issues possibly?
 
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