High oil temperature on N14 celect plus

I have 2000 Cenutry with N14 celect plus engine. A few weeks ago I hit million miles mark. Last week I noticed oil temperature going up. For example: bobtail at 65 mph with outside temperature of 80F I was getting oil temperature of 220F usually it was about 190-195F. When pulling a 30K load tempature jumps to about 230F when it usually was about 200-205. When truck is idling and warmed up temperature is about 190F where it should be. Oil pressure is fine, water temperature is fine. Today I did change oil thermostat, oil temperature sensor and oil cooler was taken out, cleaned and checked under pressure for leaks annd it came out ok. Even oil bypass sensor was taken out and inspected for unusual wear, but this is fine as well. At this point no one knows what might be a cause of this all the sudden tempature rise. Anyone had similar problems? Any advice? I need to drive and sitting home is not an answer. Please help. Thank you.

 

It is strange. Even more strange this is that there is no relationship between water and oil temperatures. Today is sunny and about 80 in Chicago. Was running with 45k load on about 15 mile stretch of highway and noticed that water temp is about 175-180 and oil temperature is 230. Even when fan kicks in at about 205 oil temp is still the same. So what I'm saying no matter what is the temp of water with or without fan on oil temp will not come down unless I take a foot of gas pedal. It only cools down by a few degrees when not accelerating or going down a hill. Can't imagine what temps I'll get when it's really humid and hot here. Read many posts and some say it normal. For me it is strange as for past 10 years driving this truck oil temperature didn't go over 210 when going up hill and usually stayed just under 200 when cruising. Maybe I was running cold all these years and new temps are the way it should be. No idea. Couple of mechanics I know have no clue either. Advise they gave me: run it, watch oil temp and see if you hear anything knocking under the hood. Well, I'm out of ideas and doing overhaul is not an answer or option at this moment. Thank you.

 

Pretty sure gauge is fine. I have manual gauge and celect roadrelay which is digital. They're both showing same numbers. Computer was hooked up to ecm and it reads same numbers as gauges. I read somewhere that I might get a code and check engine light somewhere in 250's. Hope I'll never have to find out but it's a big possibility. Thank you for your help Vision.

 

Cooler looked good. Took that to radiator shop. They cleaned it and pressure tested. No leaks, wasn't cloged. Another thing I was thinking is yhe bypass valve located in oil filter housing. From what I understand it closes when truck is cold and opens up when certain oil tempature is reached. Mechanic took it out, cleaned it and visually inspected. He didn't change it because had no parts. I'm thinking about replacing it. It shouldn't cost much. Besides he wasn't able to say if it was working or not. I don't think there is a way of determining if it works. Will have to make a trip to cummins get parts and perhaps ask service what they think about this whole situation. Maybe they had problem like that in past. Maybe they will be kind enough to give me advise of some sort besides telling me to put truck in, wait a few days and pay bill in thousands lol.

 

Yes okiedokie I'm reading thru and also answering. Thank you for link.