Ok Mark, will do. So by cold soak you just mean sitting overnight cooling off right?
Then in the morning start it up and check temps right away and then when up to temp. I guess Im not sure what to do.

 

You need to get the oil and coolant down to the ambient temps. Basically the oil, coolant, and outside air temps need to all be the same. Usually my engine needs 10+ hours to all equalize.

Chances are that you have some bypassing issues as mentioned above, but it COULD be a biased sensor (hope so anyway).

 

Ok then what do I do?

 

If the oil temp never drops down as low as the coolant temp, then you need to replace the oil temp sending unit (sensor).

btw - the oil temp sensor is the same part as the coolant temp sensor.

 

At least he has a month before the big trip... Any tricks to diagnose the bypass Mark?

And just anecdotally: I thought my temp spread grew when I did my work -- I just hadn't tracked the temps as closely as you have and after several Hard trips, I now know mine is working as good as it gets...

 

Ok, I'll check it out tomorrow morning and report back here with results.

I'd rather replace the sending unit than the filter base.

THANKS!!

 

If you have about 10 minutes, Id pull the oil filter and just look down in there for anything out of place.

 

After cold soak (16 hours) ECT is 78 and EOT is 80.

Out side temp is 69.

Its raining so I can't pull the filter yet.

 

Even though you didn't quite get a full cold soak, it should be good enough.

So it is possible that your actual temperature differences are 2 degrees less than is indicated (which puts them in a "more reasonable range". You can always swap the sensors (ie clean them and then put the ECT in the EOT position and vice versa) .... then see what the differentials are.

Actually, since gauges do not typically display decimal points, the ECT could be close to 77 and the EOT could be close to 81 - making the offset another degree or more. It is somewhat unusual that it developed the offset immediately after your work, but it could have been bumped.

 

Ok thanks Mark that makes sense. They are basically in the same area I think.
And thanks for keeping you eye out for my update this morning. :-)

Edit: I was hoping that the spread would be in the 2-4 degree range after what I've done. As for diesel engines in general this one is very sophisticated and a technological marvel, IMHO. Almost too sophisticated to the point where one little thing can stop the engine.

 

I just checked the 6.0 bible and see where they are. Piece of cake.

 

I was having similar issues for a few months. Different mechanic performed oil change and temps back to normal. Only thing I can think of is previous install of oil filter was incorrect. I would check the filter easy enough to do.

 

I did all of the work....maybe its too tight...or too loose. When the rain stops I'll head out and remove and install. then swap the sensors like Mark said.
If Mark is correct and the oil temp unit is reading 2 degrees higher, then my before spread was really good, about 7 degrees!!

 

did you happen to look at your 2 sensor's volts by chance? it doesn't seem like this is your problem but its a free check and its raining out so what else you got to do?! look up on dieseltechron's youtube channel and his last 2 vids talk about the importance of looking at the sensors volts vs the sensors readings.

 

I'll check out the videos. thanks