How hot is too hot? (Part 2)
- Thread starter Nick R
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I'm going to vote for "normalish".
Regular oil can take 260. It might be kinda thin but it'll go back to its normal self none the worse for wear. Ten years back the mobil one ads with the frying pan heated it up to 450+F, IIRC.
TL/DR, I had a mongrel Saturn with a cylinder head off a later year that didn't have provisions for a dash temp gauge. So I took my extra sender and jammed it in a threaded hole on the outside of the block that DOES NOT SEE COOLANT. The sender was calibrated to have coolant flowing over it.
Under
Above 50 MPH, though, the outside of the head got warmer and the gauge was nearly or completely pegged at "danger-red-hot", about 240'F.
I think you have the same thing going on. Best bet is to open the oil fill and stick a meat thermometer down into the oil. Even beaming an IR gun might not be accurate as it could pick up from the metal of the threads around the dipstick hole leading down into the sump.
However, cool story and pic.
Regular oil can take 260. It might be kinda thin but it'll go back to its normal self none the worse for wear. Ten years back the mobil one ads with the frying pan heated it up to 450+F, IIRC.
TL/DR, I had a mongrel Saturn with a cylinder head off a later year that didn't have provisions for a dash temp gauge. So I took my extra sender and jammed it in a threaded hole on the outside of the block that DOES NOT SEE COOLANT. The sender was calibrated to have coolant flowing over it.
Under
Above 50 MPH, though, the outside of the head got warmer and the gauge was nearly or completely pegged at "danger-red-hot", about 240'F.
I think you have the same thing going on. Best bet is to open the oil fill and stick a meat thermometer down into the oil. Even beaming an IR gun might not be accurate as it could pick up from the metal of the threads around the dipstick hole leading down into the sump.
However, cool story and pic.
JHZR2
Staff member
I'd vote normal. Newer cars with a lot of power see these temps. Air cooled outdoor equipment probably always has, thus the recommendations for straight oils and now syns.
I now on my MB diesels, which have viscosity-temp charts, sae30 can be used to much higher ambient temps than an sw-30, notionally because it holds up better.
The big question is if it matters (if the oil breaks down or sludges, will deposits form and cause issues in such a crude engine?) , and what the lowest temps you'll see. Do you have an hour meter?
I'd consider going to an sae 40 if you're doing this a lot in these temps. Of course it may require extended idle warm up times to run well in the colder conditions.
I now on my MB diesels, which have viscosity-temp charts, sae30 can be used to much higher ambient temps than an sw-30, notionally because it holds up better.
The big question is if it matters (if the oil breaks down or sludges, will deposits form and cause issues in such a crude engine?) , and what the lowest temps you'll see. Do you have an hour meter?
I'd consider going to an sae 40 if you're doing this a lot in these temps. Of course it may require extended idle warm up times to run well in the colder conditions.
Normal. Air cooled engines don't have the luxury of a regulated cooling system. Air-cooled motorcycles see the same. water always boiled "vigorously" when landing on my bike, or other mowers on a hot day, which is greater than 212.
Keep in mind that in normal automotive engines, oil splashes against +500F pistons, +350F rods, etc.. Plenty of studies show the different temps present within engines, all higher than the cooling medium.
Keep in mind that in normal automotive engines, oil splashes against +500F pistons, +350F rods, etc.. Plenty of studies show the different temps present within engines, all higher than the cooling medium.
Originally Posted By: JHZR2
I'd vote normal. Newer cars with a lot of power see these temps. Air cooled outdoor equipment probably always has, thus the recommendations for straight oils and now syns.
While I've not tested new car oil temps, I have owned many performance cars and driven a number of road race cars with oil temp gauges. In addition to operating air cooled aircraft with oil temp gauges. There is one commonality. Oil temps are never allowed to reach 260. That's well into the danger zone.
A common race car limit is 220 in the sump, 180 at oil cooler outlet. Absolute Redline of 240 AND 240 is to be avoided!
Also, one other common issue, oil temps over 220 generally result in loss of oil pressure.
I can't imagine today's cars with 5W-20 oils, high RPM capability and impressive output per displacement running anywhere near 260F in any mode of operation.
I'd vote normal. Newer cars with a lot of power see these temps. Air cooled outdoor equipment probably always has, thus the recommendations for straight oils and now syns.
While I've not tested new car oil temps, I have owned many performance cars and driven a number of road race cars with oil temp gauges. In addition to operating air cooled aircraft with oil temp gauges. There is one commonality. Oil temps are never allowed to reach 260. That's well into the danger zone.
A common race car limit is 220 in the sump, 180 at oil cooler outlet. Absolute Redline of 240 AND 240 is to be avoided!
Also, one other common issue, oil temps over 220 generally result in loss of oil pressure.
I can't imagine today's cars with 5W-20 oils, high RPM capability and impressive output per displacement running anywhere near 260F in any mode of operation.
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The problem is a lot of people are comparing auto temperatures with air cooled equipment temperatures. That is hot, but that's not dangerously hot. Dangerously hot, you start hearing the bearings knocking and that's the oil breaking down. These air cooled engines can take the heat a lot better. Tell tale signs are black smoke from the exhaust, now things are getting hot and the knocking. I see it a lot on the Harley riders here in Daytona. It will get crazy and bikes will line up on the road for miles,waiting to get into the Cabbage Patch for Coleslaw wrestling. It will be super hot in Florida and the Harleys will start overheating(air cooled, no air flow) they will shut off, the owners, mostly doctors, lawyers, etc... not mechanically minded indiviuals, will start them up and rev the snot out of them, blowing black smoke, only to have it shut off again, because its so hot. I would use any 15w40 truck oil. Believe me, that is tough oil. Nothing you can do to that stuff in a lawnmower, is worse than the environment it was designed to go into in heavy trucks and equipment.
Originally Posted By: Cujet
While I've not tested new car oil temps, I have owned many performance cars and driven a number of road race cars with oil temp gauges. In addition to operating air cooled aircraft with oil temp gauges. There is one commonality. Oil temps are never allowed to reach 260. That's well into the danger zone.
A common race car limit is 220 in the sump, 180 at oil cooler outlet. Absolute Redline of 240 AND 240 is to be avoided!
Also, one other common issue, oil temps over 220 generally result in loss of oil pressure.
I can't imagine today's cars with 5W-20 oils, high RPM capability and impressive output per displacement running anywhere near 260F in any mode of operation.
The Chevrolet Power Manual I have gives a limit of 300F in the pan.
I have run the oil in my Corvette above 260F routinely during track days for about 15 years, and it hasn't been a problem.
I used to run 200 hour Hot Box endurance tests on engines at Cummins where the oil temperature was 280F. This was on Premium Blue conventional. Never had a problem.
While I've not tested new car oil temps, I have owned many performance cars and driven a number of road race cars with oil temp gauges. In addition to operating air cooled aircraft with oil temp gauges. There is one commonality. Oil temps are never allowed to reach 260. That's well into the danger zone.
A common race car limit is 220 in the sump, 180 at oil cooler outlet. Absolute Redline of 240 AND 240 is to be avoided!
Also, one other common issue, oil temps over 220 generally result in loss of oil pressure.
I can't imagine today's cars with 5W-20 oils, high RPM capability and impressive output per displacement running anywhere near 260F in any mode of operation.
The Chevrolet Power Manual I have gives a limit of 300F in the pan.
I have run the oil in my Corvette above 260F routinely during track days for about 15 years, and it hasn't been a problem.
I used to run 200 hour Hot Box endurance tests on engines at Cummins where the oil temperature was 280F. This was on Premium Blue conventional. Never had a problem.
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I have seen 300 degrees on my car at Homestead during track events, never missed a beat. I had lunch with senior SRT engineers at my first event and they said there were no problems with quality synthetics at those temps. My UOA's were all good for 3 different events at 260-300 degrees oil temp.
Note that we run 15w-50 in our mower, 3-4 hours in Fl heat with high grass is brutal on an old design like the Briggs pictured!
Note that we run 15w-50 in our mower, 3-4 hours in Fl heat with high grass is brutal on an old design like the Briggs pictured!
aircooled VWs would respond to overtemp by simply seizing. they'd cool, you'd restart, and be on your way. Being that they'd do this repeatedly without puking the bed, seems like the oil breakdown and cylinder damage was not a big issue.
???
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Originally Posted By: meep
aircooled VWs would respond to overtemp by simply seizing. they'd cool, you'd restart, and be on your way. Being that they'd do this repeatedly without puking the bed, seems like the oil breakdown and cylinder damage was not a big issue.
???
Haha, my father had a late 50's ish VW and said this would happen all the time pulling into a toll plaza and waiting on really hot days.
aircooled VWs would respond to overtemp by simply seizing. they'd cool, you'd restart, and be on your way. Being that they'd do this repeatedly without puking the bed, seems like the oil breakdown and cylinder damage was not a big issue.
???
Haha, my father had a late 50's ish VW and said this would happen all the time pulling into a toll plaza and waiting on really hot days.
Perfectly normal and fine. The OP never told us what oil he is using, and that is what the point of this sight is, isn't it?
Any SAE 30, 10W30 synthetic, or 15w40 will be fine for these conditions.
Any SAE 30, 10W30 synthetic, or 15w40 will be fine for these conditions.
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