What is Severe Usage?

[lovcom]

I've been reading and learning alot on this great site. I've read the good Doctor's Oil White Papers (what's his name?), and found lots of good information there.

From what I gather so far, sitting in bumper to bumper traffic on a 100F day is not necessarily severe usage since the coolant temperature is probably 212F or lower (189F in my Yaris), and since the coolant is fairly constant more or less, I would imagine the oil temperature to correlate fairly closely with the ups and dows of the collant temp.

It seems that my idea of "severe" is based more on traditional thinking then in fact. It seems that severe driving is short trips around town, with frequent starting of the engine, and usage were the oil never really gets to it's optimum operational temperature.

Anyone care to comment on this, and help me learn about what is truly severe and what isn't?

The thing that confuses me is that if one drives in 110F heat, or if one drives in 32F cold, the coolant and oil are perhaps the same regardless, or at least very close, or so it seems....hmmm.....

 

[Gary Allan]

In the context of your conditions ..fuel usage is the key. You don't have the warm up issues that you're aware of ..but you can probably see where there is a "time" component that can be more easily seen in terms of fuel usage. Idling ..etc. will evidence itself in consumption. This will shorten or elongate the mileage in a self regulating manner. Since it's cumbersome to integrate a consumer level fuel tracking method of determining oil change intervals ...a blanket number has been pulled out of some (many) engineers' behind(s) and the 3k/3m figure was made a panacea for all insults. OLM was the answer to this problem.

Your oil may or may not track your coolant temp. Under load, it (generically) is based on combustion cycles per minute. It very much mimics a kinetic like action after it reaches thermal saturation (the engine parts). Essentially, the oil reads the thermal "back pressure" that the exhaust and coolant jackets don't process. You may achieve even higher idling oil temps just due to lower oil/coolant flows ..but under no load they're not much of a issue.

 

[Laminar Lou]

I would add that your coolant temp gauge is (most likely) not a true indication of coolant temp. I have a scangauge that is plugged into my ODBII port and I noticed on my Honda that temps from 175-210F don't move the needle on the dash at all. Same goes for the Toyota I own. It hits the normal range at about 155F and stays there. It doesn't move at all from 155F to 190F.

 

[glenncof]

L.Lou,

I don't understand. Isn't the guage and scanguage reading the same sensor ?

The dash guage is probably slow and perhaps non-linear relative to the scan. The temp is set by thermostat unless you're running out of cooling capacity. I could imagine thermal transients as thermostat is slow responding.

 

[glenncof]

"Severe" is usually defined by the manufacture. But you got the idea...most manufactures don't define a mom with school-age children shuttling them around as "severe".

 

[SubLGT]

Subaru has recently declared that all their turbocharged vehicles fall under the severe usage description, regardless of how they are actually used.

 

[Quattro Pete]

Quote:

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L.Lou,

I don't understand. Isn't the guage and scanguage reading the same sensor ?

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Yes, but there is a computer between the sensor and the gauge, and the computer is telling the gauge not to budge within a certain range of operating temps, like the ones Lou mentioned. This is done in order to not alarm the driver that there is something going on by not having him see a fluctuating needle. Basically, the gauge is programmed to have a dead range. Many car manufacturers do this nowadays. VW, Audi, BMW, to name a few. It's basically a dummy gauge that is supposed to move only if the coolant temp moves very far away from normal.

 

[Laminar Lou]

Quote:

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L.Lou,

I don't understand. Isn't the guage and scanguage reading the same sensor ?

The dash guage is probably slow and perhaps non-linear relative to the scan. The temp is set by thermostat unless you're running out of cooling capacity. I could imagine thermal transients as thermostat is slow responding.

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Yes they are using the same data, but there is some logic controlling the needle and there is usually a "damper" on it so as not to freak out the driver. Ford is known for this in their oil pressure gauges. Google "ford fake oil gauge". I've talked to others and this seems to be common for many OEM coolant gauges as well.

It's funny, I've known about the Ford oil pressure gauge for some time but never realized that the OEMs might be doing the same thing for the coolant temp gauge too. Then I got the scangauge and I realized I have been lied to all my life

That's why I mention it.

 

[psudaytona]

Lou, I noticed this with the 98 crown vic I just picked up. Its temp normally sits at about 1/3 the way up and does not seem to swing even in traffic with the AC on. I just passed it off as due to the police colling package it had.

If I bought a cheap scangauge, would I be able to see the real temp and oil pressure? Also, of the ford, can a scangauge see engine RPM? Mine has no tach.

 

[Lonnie]

Gauges are often "stabalized", that is they read in one position for a wide range of actual temps. The ScanGauge reads the temperature and reports its actual value.

 

[lovcom]

So back to my original question, at least one of them: If the oil is up to operational temperature and I'm stuck in stop & go traffic on the freeway, and the outside ambient temperature is 105F, is my car being used in severe conditions? Since the coolant temp is fine, the oil temp is probably fine, oil is flowing bathing the internal engine parts, what is so severe about that?

 

[lazaro]

Quote:

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So back to my original question, at least one of them: If the oil is up to operational temperature and I'm stuck in stop & go traffic on the freeway, and the outside ambient temperature is 105F, is my car being used in severe conditions? Since the coolant temp is fine, the oil temp is probably fine, oil is flowing bathing the internal engine parts, what is so severe about that?

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what type of vehicle is this?

 

[AEHaas]

Oil takes up to 30 minutes to get up to operating temperature. If you do short trips that are less than 30 minutes duration then this is severe conditions for your oil as it does not get hot enough, long enough to burn off fuel and water dilution.

It is important to note that your water temperature gauge is not related to oil temperature. People do not believe this unless they have both gauges to view. Water heats up in a few minutes, oil takes up to 30 minutes to get up to operating temperature. It needs to be run longer than this to Help the oil last longer. Running engines too cool or too hot are both bad. Short trips are bad for oil because the oil does not get enough use at normal operating temperatures.

aehaas

 

[Curious Kid]

Just because you're sitting in traffic doesn't seem to me like it's stressing the oil all that much, at least that's what I'm thinking. Took a trip yesterday and noted the oil temp hovering around the 220 degree f. mark while traveling steadily around 65mph. Having taken the off ramp and now waiting at a light, the oil temp began dropping. Around town it hovers just over 200 degrees f. The Aux cooling fan for the coolant radiator was off the entire time on the interstate w/ac, but would cycle in town. Throw in various flow rates of coolant and oil, heat exchange rates and capacities and load...it all kind of presents as Gary mentioned.

What makes an acceptable lubricant (base oil and any additives), go bad? Go from there...gallons of gas, CFM's of air, fuel quality, mechanical state of repair/tune, sump volume, air exposure, crankcase ventilation ability, fuel/coolant/condensate/other contamination and said duration even though remains will exist after boil-off, mechanical surface area for which operates in mixed film/boundary regimens leading to such additive uptake (thinking revolutions with a piston-in-cylinder, or cycles otherwise), etc. I'm no engineer by any means, and even so I don't know all the specifics involved with the engine in the vehicle(s) I use...so unless used oil analysis are utilized than I will take the information provided to me by the manufacturer as necessary. One could deviate a little with some understand and modifications in behavior of use, but that's only as good as it is fact...

As for the dummy gauge - my mother's volvo 240dl had the compensation circuit go which was mounted on the back of the instrument panel. Simply removed and installed a bypass/jumper wire as I discovered from IPD. Though the gauge is slow to respond (In viewing I think it's somehow thermally actuated rather than via electromagnet), it's now more true in representation.

 

[Curious Kid]

Just because you're sitting in traffic doesn't seem to me like it's stressing the oil all that much, at least that's what I'm thinking. Took a trip yesterday and noted the oil temp hovering around the 220 degree f. mark while traveling steadily around 65mph. Having taken the off ramp and now waiting at a light, the oil temp began dropping. Around town it hovers just over 200 degrees f. The Aux cooling fan for the coolant radiator was off the entire time on the interstate w/ac, but would cycle in town. Throw in various flow rates of coolant and oil, heat exchange rates and capacities and load...it all kind of presents as Gary mentioned.

What makes an acceptable lubricant (base oil and any additives), go bad? Go from there...gallons of gas, CFM's of air, fuel quality, mechanical state of repair/tune, sump volume, air exposure, crankcase ventilation ability, fuel/coolant/condensate/other contamination and said duration even though remains will exist after boil-off, mechanical surface area for which operates in mixed film/boundary regimens leading to such additive uptake (thinking revolutions with a piston-in-cylinder, or cycles otherwise), etc. I'm no engineer by any means, and even so I don't know all the specifics involved with the engine in the vehicle(s) I use...so unless used oil analysis are utilized than I will take the information provided to me by the manufacturer as necessary. One could deviate a little with some understand and modifications in behavior of use, but that's only as good as it is fact...

As for the dummy gauge - my mother's volvo 240dl had the compensation circuit go which was mounted on the back of the instrument panel. Simply removed and installed a bypass/jumper wire as I discovered from IPD. Though the gauge is slow to respond (In viewing I think it's somehow thermally actuated rather than via electromagnet), it's now more true in representation.

Take care.

 

[Curious Kid]

*posting issue*

 

[gedcruise]

Well, as others have posted, you don't have a clue as to the actual oil or coolant temps.
If the car realy needs oil cooling, it will usually have an oil cooler (small radiator for the oil), which depends upon the flow of air, through movement of the vehicle, to cool the oil. Otherwise, the only cooling the oil gets is from the cooler parts of the engine, as well as its time in the sump, which is cooled by the flow o air induced by the movement of the vehicle.
What I am trying to say is that the oil might get dangerously hot, and you would never know it.
OLMs take this into account. Extremely hot running conditions reduce the allowable limits for oil life per the OLM.
For me, we are having our second week of 90 F+ heat in this part of the state, so I am happy to be running GC in one car, and PP in the others. The recently deceased Benz had GTX 20W-50, per MB's owners manual.

 

[Curious Kid]

Though ambient temperatures do have an effect on oil temperatures, what I believe is more critical is just how much is being asked of the engine, and thus of it's lubricant. Put a given amount of work over time and compare to how the differing heat uptake of the coolant and oil, and thermal transfer between the two through the engine block...to a degree they are shared systems, but not efficiently designed and layed out to be as such under the hood of a "typical" consumer vehicle. Install a fluid to fluid heat exchanger (oil to coolant), and the thermal relationship becomes closer. Such systems are more often the case for automatic transmissions (cooler integrated in the outflow side of the coolant radiator).

Moderator: Could you please delete my first and third post above - I tried the editing process to only discover that it would still create a new post. Thanks.

Take care.

 

[Curious Kid]

Quote:

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If the oil is up to operational temperature and I'm stuck in stop & go traffic on the freeway, and the outside ambient temperature is 105F, is my car being used in severe conditions? Since the coolant temp is fine, the oil temp is probably fine, oil is flowing bathing the internal engine parts, what is so severe about that?

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The only thing that is different here without taking cooling airflow into account as one has stated that oil temps are OK, is the flow rate of oil that's bathing the internals. Lower rpm's = lower flow rates of oil. I wouldn't think that hotspot are more likely to develop while at idle than at some higher steady state of operating, but thermal "ramping" could briefly occur as when one immediately comes to a stop after laboring the engine - things will momentarily heat-up as the higher heat levels continue to transfer through the engine structure, eventually to be handled by coolant, oil, and/or to the open air that would otherwise be flowing around the block. That aside, lower speeds of operation for areas that might spend little time in hydrodynamic regimens, could be experiencing an increase mode of operation in mixed film and/or boundary lubrication. This might increase the uptake of additives compared to other states of operation, or it might not. It all depends up the design and implementation of the engine and lubricant. That leaves me with...

Take care.