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Oil temp rising

1557 Views 6 Replies 4 Participants Last post by  RT
The oil temp on my 7.3 stays around 140 from what the gauge says but after 20 min or so of driving the oil temp will slowly rise to almost 190 when not cruising at about 40. Once I get up and going again it drops fairly quickly. It has fresh oil and is full. I don't think it is an unsafe temp but don't think it's right that it raises like that. Any thoughts?
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I have a oil temp gauge at the port by the filter - that would make it before the oil cooler. My oil temp runs 190° constant after getting up to operating temperature. Where are you measuring temperature? If it is from the PCM value, that sender is in the HPOP reservoir, which is after the cooler. That would mean the oil is being cooled down to 140 by the cooling system while you are moving. That may mean your thermostat could be stuck open and not keeping your coolant at 180°. I haven't monitored that value - maybe I'll program the ScanGauge to watch that value so I can monitor the delta. To answer your base question, though - 190 isn't too hot - its just right.
The 6.0 guys pay a lot more attention to this than we do - mainly because their oil coolers and EGR coolers are rupturing all the time. I've read where a 15-20° difference running unloaded is normal. That would be oil hotter than water by that amount. Loaded, the values can go higher. 220° for the oil is nothing. It really sucks that we don't have an easy way to monitor coolant temperature - it would make for some interesting comparisons.
The factory coolant gauge sender is little more than a switch - when it gets to a certain temperature it jumps to normal, and then above another temp it jumps to red - no gradual movement with temp changes.
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