Oil heat punishment

Messages
11
Location
sweden
Simple(?) question: How much heat can a modern synthetic motoroil take, or are there no given guidelines? Previous I hade a BMW M3 -96 and the user manual said - "For short times you can let the oil get up to 130C (266F)." To me that is hot! But when is the oil "used up" of the heat-treatment? one 130C run, or two 130C runs, or hundred 130C runs? Does this show in a UOA? What oiltemps do you usually have during "normal" driving? I have one car with tempgauge (Corvette C5 -00) and it stops around 92C (198F) (I'm using M1 0w-40). Are there any data from the oilmanufacturer that can give a hint on this, or is it trail and error?
 

TC

Messages
1,644
Location
California
"How much heat can a modern synthetic motor oil take...?" I can't directly answer your question, but would suggest that a synthetic oil wouldn't be the weak link or component to worry about -- your engine, including head warpage and head gasket failure, might be the things to fail first. Your engine components would be the limiting factor, rather than the syn oil itself. If you're heating syn oil up so much that you're substantially decreasing the oil's lifespan, you'll probably experience some sort of engine damage soon anyway. The usual oil performance standards, such as base stock grouping, NOACK Volatility Test, Viscosity Index, TBN, etc., all play a role in high-temp oil performance. "What oil temps do you usually have during 'normal' driving?" One group of Ford enthusiasts claim this: "Oil works best over a narrow temperature range of 220 F to 260 F degrees." http://www.shoclub.com/lubrication-oil/lubrication-oilpart2.htm So long as your cooling system (including water/oil temp gauges) is functioning properly, and assuming you're NOT overly stressing your lube temperatures such as during track racing or heavy towing in summer, personally I wouldn't worry too much about oil temps or installing an oil cooler for that matter, and have faith in the the factory (water) cooling system. If you DO stress the engine over long periods, that's another story... [ July 02, 2004, 07:54 PM: Message edited by: TC ]
 
Messages
2,628
Location
MN
quote:
"Oil works best over a narrow temperature range of 220 F to 260 F degrees."
I don't think many of todays engines will get the oil that hot in normal operation. Race cars barely get this hot in an 800 HP engine.
 
Messages
12,385
Location
Northern CA
quote:
Originally posted by tmorris1:
quote:
"Oil works best over a narrow temperature range of 220 F to 260 F degrees."
I don't think many of todays engines will get the oil that hot in normal operation. Race cars barely get this hot in an 800 HP engine.

That temperature range is BS. It's about 30 degrees high. Dino oil ife starts to deteriorate above about 230-235 F. His comment that oil is too thick below those temperatures only means he was using the wrong viscosity oil for reasonable operating temperatures.
 

Al

Messages
19,256
Location
Elizabethtown, Pa
At wide open throttle engines can get to higher 200's F say 280F . That brings a normally 10 cSt oil (30 wt) at 210F to a 5 cSt oil at say at 280 F. Asynthetic can take these temperatures forever but a dino oil will have serious shortening of life. Running at these higher temps for long periods of time might require a 40 wt. oil (at least) But remember a heavier oil will on its own raise temperatures due to less flow. Synthetic oils will not "use up " at 266F. Conventionals oil will. A UOA will tell how the oil really did. Probably normal temps for oil on hotter days in normal driving are 240F or so-,maybe a little lower but could be hotter possibly.
 
Messages
300
Location
toronto
My oil temp is at 100C during 30 min Highway runs. More than that the temp goes up to 105 to 112 c. It is a VW and VW are known to run high oil temp. during race my oil temp gets up to 120C or past that point. I used AMSOIL 20W50 and oil analysis didnt show anything bad.
 
Messages
52
Location
Washington DC
quote:
vazzen: Simple(?) question: How much heat can a modern synthetic motoroil take, or are there no given guidelines? Previous I hade a BMW M3 -96 and the user manual said - "For short times you can let the oil get up to 130C (266F)." To me that is hot!
Somewhere over 300 F seals start melting. Somewhere over 400 F the oil burns. It's not only "how much" but "how long". Short higher temperature spikes and sustained high heat are two different things. In some applications (air-cooled V-twin motorcycles) at the boundaries (piston rings) I have a feeling temperatures go over 300 F, but the amount of oil there is very small and very little of it returns to the crankcase.
 
Messages
4,630
Location
Decatur AL USA
Some street cars can reach 300ºF Oil Temp on the track. LS1 Corvettes and the M3 comes to mind. I am not to worried with the oils that BMW usually calls for. I am a bit concerned about 5W-30 Mobil 1 under these conditions. On the street the place I would be concerned about oil temps if if you normally make a extreme conditions run. A example is the run up North Bound I-15 from Las Vegas NV to the I-70 junction. There is a 40 mi Stretch with a average upgrade of 3.5% in Southern Utah were temps can often be between 100 and 120ºF. Given most cars run this stretch between 75-90 mph you can see the potential is there to be very hard on a low vicosity dino oil. In a Diesel with a 10.5 gal Sump and Engine Coolant Cooled Oil Cooler I have often seen oil temps of 250ºF on this stretch. This also resulted in raising the coolant temp from 195ºF to 220ºF inspite of running the engine fan. Gene
 

tpi

Messages
200
Location
So. CA
quote:
Originally posted by Gene K: In a Diesel with a 10.5 gal Sump and Engine Coolant Cooled Oil Cooler I have often seen oil temps of 250ºF on this stretch. This also resulted in raising the coolant temp from 195ºF to 220ºF inspite of running the engine fan. Gene
A semi on topic rant: Dumbed down gauges in many newer vehicles. I just completed a trip to the lower Colorado river valley in my '04 Camry. Ambient temps were to 116 degrees F. Highway 40 moves about 80 MPH for car traffic, AC blasting numerous grades. Temp gauge never budged from "normal" position. Shut off car for 5 minute hot soak, this should bring up coolant temp at least 20 degree F. Still no movement of gauge. Have seen temps as high as 124 on this stretch. Drove my F250 diesel at the time, no movement of gauge but heard fan working hard. No movement during hot soak, no movement of oil pressure gauge at idle. Alternator on this truck recently failed with no movement of voltmeter from the normal position (the alternator wasn't charging at all). Why bother with these stupid semi inoperative or completely inoperative gauges? They give a false sense that everything is running cool when actually temps are at the top of the design range. I'm more concerned with the seals as the oil temps push 300 degrees. The oil can be easily changed. Perhaps the most important factor is how much time are the seals and oil exposed to the excessive temps.
 
Messages
6
Location
VA
Dummy gauges are for those owners who are not familiar with what should or should not be happening under the hood and get an itchy trigger finger to call the dealer for every seeming irregularity. "Oh my gosh! The car is getting hotter after I turned it off! Something must be wrong, I gotta call the dealer!" Or "The temperature is rising even though I have the AC on, better call the service department." I have two cars, an 86 and a 00. The 86 has real oil pressure and coolant temp gauges; the 00 has dummies. The 00's oil pressure gauge will stay at midrange as long as the psi is 6 or more; now that's what I call progress in automobile instrumentation. How about an I-am-not-an-idiot-and-want-real-gauges package for those buyers who can pass a competency test?
 
Messages
3,334
Location
Bolivia
I ran an UOA on Delo after a race where the radiator got clogged from a slower car that refused to move over. It was worse because a bolt losened in the transmission linkage and for the latter part of the race 3rd gear was max. (still took 3rd place). The oil temp at the end of the run was 315 F with a pyrometer on the filter (located between the fan and the block). Oxidation was 5%, visc 13.99 Only problems shown were from the K&N filters that let 63 ppm of dirt in for 62 ppm of iron wear. We ran aviation gas, so the 387 ppm of lead was expected. Race was only 10 laps on an 8 km winding dirt track. Oil was in for practice, two qualifiying races and the actual race. Total of about 200 km. The oil gets super hot for the moments it spends in the turbo. I've never tried to check that, but read an Exxon publication once that claimed it was at 280C / 536F in the turbo.
 
Messages
164
Location
USA
quote:
Originally posted by Gene K: A example is the run up North Bound I-15 from Las Vegas NV to the I-70 junction. There is a 40 mi Stretch with a average upgrade of 3.5% in Southern Utah were temps can often be between 100 and 120ºF. Given most cars run this stretch between 75-90 mph you can see the potential is there to be very hard on a low vicosity dino oil. Gene
Glad you mentioned that. I drive through there on my vegas trips and yep I've been through there when it's 112 to 115 in Vegas so it may even be more through there. That makes the point for me of why I won't run 5W-20 weight oil in my Honda's at least during summer time.
 
Messages
718
Location
Central Texas
I'm not sure if this will help. Here is a little more data. I've been running turbo oil outlet temperatures on my TDI. Mostly I wanted to know how long of a cool down cycle I needed. I'm confident the temps are reasonably accurate. The ambient temp on the thermocouple matches air temps after an overnight resting period. At full operating temp the turbo outlet ranges from 221* to 228*f. Ambient temps range from the 50s to the upper 90s and have had no effect on the outlet temp. or cool down rate at idle. Ambient temp does significantly effect how fast the oil gets up to operating temperature. For those that are curious at idle it takes one full minute to cool down to below the 200*f mark and four full minutes to cool down below 170*f.
 
Messages
23,591
Just the other day I read that oil temperatures of 275-300 degr, F (135 - 150 dear. C) do not lead to increased engine wear as long as the oil still has at least 4 cst. I read that on a Ferrari forum. There were lots of charts and graphs and talk about oil, but links to that forum are verboten. [Razz] Anyway, this doesn't answer yor question, which was about whether the oil holds up to repeated heating. All I can say is that I used to see my oil temp rise to 125 degree C in my VW Scirocco when driving Autobahn, and with no ill effect during an oil change interval of 15,000 km.
 

Patman

Staff member
Messages
22,012
Location
Guelph, Ontario
quote:
Originally posted by moribundman: Just the other day I read that oil temperatures of 275-300 degr, F (135 - 150 dear. C) do not lead to increased engine wear as long as the oil still has at least 4 cst. I read that on a Ferrari forum. There were lots of charts and graphs and talk about oil, but links to that forum are verboten. [Razz]
Not anymore! You can post links to other message boards on here, just don't post a link to a sales page unless it's one of our sponsors. So let's see that Ferrari link! [Smile]
 

TC

Messages
1,644
Location
California
Original post: "How much heat can a modern synthetic motoroil take, or are there no given guidelines?" This Shell website suggests that temps in the range of 370F-430F are "extremely high temps" that "synthetic and synthetic blend" oils will perform better than dino at. It also states, "But the highest temperature of oil-lubricated surfaces inside a properly functioning diesel engine won't exceed 290F." http://www.shell.com.cn/english/product/faqs.html This is making a very large leap from those comments, but knocking off a full 100F off those numbers, arriving at 270F-330F, might suggest that synthetic isn't heavily stressed at such temps...? The second comment indirectly suggests to me that syn can accomodate 290F on a routine basis without much problem.
 
Messages
857
Location
Ohio
The Redline website states: "...upper ring area will see temperatures in the range of 600F." "...cam and follower contacts can also reach temperatures of 500F." The oil in your sump won't reach those temps obviously, but lubricating those areas is one reason why you get oil consumption - more so with a conventional oil.
 
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