Took a trip today that was 3 hours there and 3 hours back. Truck ran normal on the way there (eot about 202 and ect about 196-198), but on the way back truck ran a little hotter than normal (ect as high as 214 eot stayed within 2-3* plus or minus ect). Fan did kick on everytime I hit ect of 212 and would drop it down to 196-198 and oil temp would drop at the same rate.
Truck is stock 190k miles with a bulletproof egr cooler and coolant filter. Oil cooler probably has about 20k on it. (4th one on this truck- since I like changing them out as much as the rest of us)
I checked coolant level when I got home and I might've added a pint to get to bottom of sticker. I'm not sure it wasn't a pint low when I did last flush and cooler replacement.
No puking and I can't find any leaks. I pulled egr valve and no moisture in manifold just a worm out o ring that'll I'll replace. I can't find any leaks.
Any ideas on where to check that I havent?
I don't feel like I'm losing coolant because I wasn't really low. My fan never failed to kick on when I hit 212 or stopped at a red light. No moisture in manifold so I'm not thinking losing coolant due to head gasket. Maybe radiator looks ok but tomorrow I will blow out any bugs to make sure.
Any ideas and suggestions would be nice.
Thanks in advance

 

Btw I also looked for belt slippage and there isn't any shiny spots

 

When is the last time you replaced the degas cap? Anything else besides coolant filters you've done lately that would leave air in the system?

It sounds like you added about what a filter takes out, and otherwise your truck sounds normal. Can you give us approx ambient temps on the to vs. back trip? speed or traffic differences?

 

Degas cap was replaced when I changed out my previous oil cooler about 20k miles ago

Coolant filter was added during second oil cooler change and filter was changed out 10k miles ago

Temp was 75 on the way to and 82 on the return
Those numbers are generally what I see while towing but never while empty unless it is 100* plus and traveling up and down hills etc

I just feel like something is creeping up to becoming an issue and I wanted to stay in front of the problem before I start seeing severe temps

 

So I would say you are no more paranoid than the next, just observant, like we all should be -- just the nature of the beast.

I'd check degas level at same pretty much exact parking location, cold, a few times and watch that. But my bet is you are looking at a water pump starting to go...

 

your temps don't seem too bad, although, definitely a little high for those ambient temps. Was there a lot of stop-and-go traffic on the way back? That's the only time, besides towing or steep hills, that I ever see my coolant go over 200F.
I would just keep an eye on the coolant level, temps, and check for any debris that may be restricting airflow around the radiator. If it were me, I would give it a little more time before throwing parts at it, unless the problem gets worse.
It sounds like you're being smart about it and staying on tops of things before something expensive happens. keep us updated.