How hot is too hot for EOT?

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Bremerton, WA
I am using Rotella 10W-30 and noticed my engine oil temps are running around 220-223 degrees while towing up mountain passes with outside temps around 85 degrees. Is this normal or am I running too hot? Griz95
 
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Richmond, VA
That's normal for heavy engine load. Typically you don't want it to go much higher than that under normal use so if it does get higher due to mods, temp increase, altitude... look into an oil cooler.
 
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Washington St.
With the engine mods you've added, and the temperature, and the heavy load of towing uphill, I'd run an xW-40 in the summer for greater film strength. If oil analyses show no increased engine wear, though, what you're doing is OK. The xW-40 might run a bit hotter, but it would still have greater film strength than the 10W-30.
 
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I read "Griz95" and for some reason you were talking about a 1995 Geo Metro. Then I saw someone saying towing up hill. I got really confused.
 
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If 10w30 works fine in a 15L engine pulling 80,000 lb in desert and mountain passes, not sure why it would not work fine for what you are doing. And Detroit even has a recommended oil change interval on their 15L of 50,000 miles using the stuff.
 

Griz95

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Bremerton, WA
I never paid too much attention to EOT before. I was mainly watching transmission temps, boost and pyrometer temps. They were all okay. I guess I'll switched to a 5W-40 oil and see what temps it'll run. If nothing else just for comparison. Thanks everyone for your inputs. Griz95
 
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Washington St.
Quote:
If 10w30 works fine in a 15L engine pulling 80,000 lb in desert and mountain passes, not sure why it would not work fine for what you are doing.
But those engines are made and tested for the 10W-30. Griz has modified his engine. His mods put more stress on the pistons to main bearing parts when he's running hard. This is why I suggested a higher viscosity oil with higher film strength. A 777 jet engine puts out 90,000 hp with 5 wt oil. A very large diesel engine puts out 100,000 hp with 30 wt. crankcase oil. Those do not relate to Griz's specific situation. The psi of the bearings is important. Not the psi of the oil supply, but the pounds of force of the piston pushing down on the square inches of bearing surface. The oil film must handle the force without failing. Griz has increased the force due to his engine mods. He can't increase the size of the bearings, so he might benefit from a stronger oil film. Other things remaining equal, higher viscosity oil has a higher film strength. The oil temperatures he shows aren't high enough to cause oil breakdown, but they thin the oil which causes a reduction of film strength. And, we don't know the actual temperature in each bearing--only an instrumented engine in the test lab has all that--but the bearing temps are higher than the sump temp.
 

Griz95

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Bremerton, WA
Originally Posted By: Ken2
Quote:
If 10w30 works fine in a 15L engine pulling 80,000 lb in desert and mountain passes, not sure why it would not work fine for what you are doing.
But those engines are made and tested for the 10W-30. Griz has modified his engine. His mods put more stress on the pistons to main bearing parts when he's running hard. This is why I suggested a higher viscosity oil with higher film strength. A 777 jet engine puts out 90,000 hp with 5 wt oil. A very large diesel engine puts out 100,000 hp with 30 wt. crankcase oil. Those do not relate to Griz's specific situation. The psi of the bearings is important. Not the psi of the oil supply, but the pounds of force of the piston pushing down on the square inches of bearing surface. The oil film must handle the force without failing. Griz has increased the force due to his engine mods. He can't increase the size of the bearings, so he might benefit from a stronger oil film. Other things remaining equal, higher viscosity oil has a higher film strength. The oil temperatures he shows aren't high enough to cause oil breakdown, but they thin the oil which causes a reduction of film strength. And, we don't know the actual temperature in each bearing--only an instrumented engine in the test lab has all that--but the bearing temps are higher than the sump temp.
Ken2...I hear you and I am switching to 5W-40 oil. Is there a 5W-40 oil you would recommend for my situation? Griz95
 
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Quote:
I hear you and I am switching to 5W-40 oil. Is there a 5W-40 oil you would recommend for my situation?
I've used the Schaeffer line of oils for years with excellent results. My gasoline Volvo turbo engine at 200,000 miles not only had the turbo running like new, but some of the factory machining marks on the cam lobs were still visible. I used Schaeffer #9000 5W-40 in this engine. http://www.schaefferoil.com/documents/244-9000-td.pdf I got the oil from Scott Birdsall ([email protected]) in Sequim. Ray Summerlin in Kent ([email protected]) is the next closest. Next down my list, and easily available, would be the Mobil Delvac 1 diesel engine oils. Amsoil Premium 5W-40 is probably very good, but pricey (I think Amsoil makes good stuff, but I don't buy into their hype). Then, any of the top brand oils. Shell's Rotella oils are perfectly OK--nothing wrong with them and nothing special about them.
 

dnewton3

Staff member
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To return to the main question, "no", that range of temps is not too hot for the oil you use. That is perfectly acceptable. Feel free to switch to a different oil, but you'll not get a substantially different result. Just for a point of reference, and not that I completely endorse the entire study, but the infamous GM filter study from 1988 ran the diesel engines at 250F oil temps, for the entire test period. OH - the Horror! crzy What we all perceive as "hot", and what is really unsafe to an engine or lube, are two totally different things. You can thank many years of marketing bombardment and brain-washing for this effect. If you really want to KNOW how things are going, then get a UOA, and quit guessing and relying on hearsay. thumbsup
 
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Griz95

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[quote=dnewton3]To return to the main question, "no", that range of temps is not too hot for the oil you use. That is perfectly acceptable. dnewton3...just for future reference what is considered 'To Hot' for engine oil? I am sending in an oil sample for a UOA soon. Thanks, Griz95
 
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I had this same question a few months back. You can check that thread out. Same engine, different year. Mine got to 235* while towing on a hot day. It was fine. What I have heard form guys that race and use their diesels in heavy use situations, 265*-280* is getting too hot, but you should never see close to those temps. I was using Rotella 10w-30 and changed it to 15w-40 on the trip where I saw mine climb. It did bring my temps down about 5*, but nothing major. I wouldn't even worry about it....just keep on going. I am not even sure I would spend the money on a UOA unless you just want peace of mind at this point. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3327348/1 There is the other thread from back in March.
 
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Sunny Florida
Wildly platform dependent but I once emailed Mobil about a track day where my car exceeded 300 degrees. They said that was no problem. Engine is still going strong 8 years later...
 

Griz95

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162
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Bremerton, WA
Originally Posted By: cowhorse01
I had this same question a few months back. You can check that thread out. Same engine, different year. Mine got to 235* while towing on a hot day. It was fine. What I have heard form guys that race and use their diesels in heavy use situations, 265*-280* is getting too hot, but you should never see close to those temps. I was using Rotella 10w-30 and changed it to 15w-40 on the trip where I saw mine climb. It did bring my temps down about 5*, but nothing major. I wouldn't even worry about it....just keep on going. I am not even sure I would spend the money on a UOA unless you just want peace of mind at this point. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3327348/1 There is the other thread from back in March.
Thanks for the info Cowhorse01...interesting reading. One time during the trip the outside temps were 105 degrees and I was pulling the trailer up into the Siskiyous. Not an idea situation for towing. The EOT readed 225 at one point until the clutch fan kicked in and it brought it down a few degrees. I think I feel more comfortable now knowing what was said in your thread. Griz95
 
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The 7.3 was originally speced for 30 wt., you're not doing any damage running 10w-30 with the temps you've reported. Personally I use 10w-30 in my 7.3 and 6.0, with outstanding UOA results, but if running a heavier oil makes you feel better go fro it, your 7.3 won't care.
 

Griz95

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162
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Bremerton, WA
Originally Posted By: roadrunner1
The 7.3 was originally speced for 30 wt., you're not doing any damage running 10w-30 with the temps you've reported. Personally I use 10w-30 in my 7.3 and 6.0, with outstanding UOA results, but if running a heavier oil makes you feel better go fro it, your 7.3 won't care.
I think I am going to send in an oil sample and see what the results tell me and go from there. Griz95
 
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