Oil Temp

[DinoOil]

I've browsed quite a few pages and didn't see this question raised. I'm fortunate enough to have a vehicle (2012 Dodge Charger) that has an EVIC(Electronic Vehicle Info Center) on the dash board. Among the nice info it displays is Oil Temperature.

When does conventional oil get too hot before it degrades/breaks down, and also for how long of an interval does the temp have to be too high? How about semi synth? And while we're at it, how about full synth too?

Sitting in hot summer traffic I believe I recall watching it climb as high as 225 deg F. I have noticed that usually, the difference between Coolant and Oil Temps have been typically at most 15 deg F. This type of question has never crossed my mind since all my cars in the past never gave such info.

 

[dparm]

225 is no problem. If the temps are holding above 250ish, then you're going to be pushing it pretty hard.

Modern dino oils are excellent, so I don't think you have anything to worry about it. Dodge would've spec'd synthetic if they thought the motor was hard on oil.

 

[RiceCake]

If your oil temperature gets hot enough to break down any oil, your engine is probably in big trouble.

Air cooled engine run on dino and get even roastier.

 

[toneydoc]

My air cooled Harley runs on dino oil most of the time and the usual operating temp is about 250 F. The rear cylinder can run even hotter. So your oil can withstand 225 with no problem. I do change my oil every 4-5k miles with a new filter. It is doing fine.

Have a beer on me

 

[Clevy]

Originally Posted By: toneydoc
My air cooled Harley runs on dino oil most of the time and the usual operating temp is about 250 F. The rear cylinder can run even hotter. So your oil can withstand 225 with no problem. I do change my oil every 4-5k miles with a new filter. It is doing fine.

Have a beer on me


Mine too.I've got a jagg 10 row oil cooler but it only dropped oil temps about 15 degrees.
Flashpoint would be the determining factor as far as what temp an oil can withstand,at what temp the oil starts degrading though is something i dont know.
At what temp does a particular oil start not doing its job as well,or starts leaving deposits?

 

[DinoOil]

Originally Posted By: Clevy



Flashpoint would be the determining factor as far as what temp an oil can withstand,at what temp the oil starts degrading though is something i dont know.
At what temp does a particular oil start not doing its job as well,or starts leaving deposits?


These are some of the things I'm interested in too.

 

[widman]

Any oil begins to oxidize over 70C. That is why engine oils are fortified with anti-oxidants and you have to change them periodically.

I presume that is the Pentastar engine. It has a nice cooling system. The water flows through the oil cooler after the radiator. You will find that the temperature of the water climbs quickly to 95C, with the oil slowly following it, but cruising more like 85 to 90C. Under a hard load or long slow climb it will get up to about 105 to 106C (the manual says to stop if it passes 116C). The oil temp will also reach 105-106 by then. As you go down the mountain or reduce power, the water temp will drop back to 100 and then the oil temp will drop to 98 or so.

I've had it full, cruising up the mountains around curves at 20-30 mph for two hours at 42C (108F) without any problems or without passing the 106C.

Chrysler says to change when the computer says or 6 months or 7500 miles.

 

[fdcg27]

I ran nothing but conventional oil in our air cooled Vanagon, which you pretty well drove flat out all the time on the interstates, and which would generate enough heat in warm weather that it was very uncomfortable to touch the rear bumper after a couple of hours driving.
When I tore the engine down after about 105K, it was spotless inside, not even any varnish.
This was on the oils available in the late 'eighties and early 'nineties.
What I'm trying to say here is that 225F on conventional oil should be no problem.

 

[DinoOil]

Originally Posted By: widman


I presume that is the Pentastar engine.

Chrysler says to change when the computer says or 6 months or 7500 miles.


Neh-ga-tory... It's the BIG BOY Hemi!

You say the Pentastar 6 cyl has an oil cooler. Does the Hemi 5.7 Ltr have one? I did the first oill change a few weeks ago and didn't notice an oil cooler. Anybody know if it does?
As far as oil change interval for this car, I'm going to go conservative and do 5000 mi oil changes.

 

[DinoOil]

Thanks for all the replies. Actually, I was never really concerned about oil temp in this car going sky hi crazy. Just because I have new info from the vehicle presented to me got me to thinking what would be the "red -zones" of oil operating at high temps.

I did a search of yahoo and google and I found surprisingly little to no answers for this question. I still would like to know how much better a semi-synth and a full synth would outperform plain-old conventional oil.

 

[bmwtechguy]

I would think that you would want the oil to get up to around 225 deg F on a regular basis to vaporize any water from the crankcase/sump and move it out through the crankcase ventilation system. Cold weather and short trips are harder on the oil's longevity than heat is for this reason. One of the biggest byproducts of combustion is water vapor, and some of it invariably ends up in the crankcase.

 

[SteveSRT8]

Note that you do not have to get anywhere near the boiling point of water to evaporate it out of your oil. 180 degrees is plenty hot if sustained for a few minutes. It's time versus temp and vapor pressure.

 

[SHOZ]

On my 2010 Hyundai 2L turbo you can't go into full boost until the oil is 140F. On the 2013s they raised this to 150F and added a water/oil heat exchanger. The people are complaining it takes forever for the oil to get to 150F so they can get their full boost.

 

[DinoOil]

Originally Posted By: SteveSRT8
Note that you do not have to get anywhere near the boiling point of water to evaporate it out of your oil. 180 degrees is plenty hot if sustained for a few minutes. It's time versus temp and vapor pressure.


I'll tend to agree with you, however the vaporization may not be significant at such a low temperature relative to 212 deg F at 1 atm. We've all watched a pot of water heating up on the stove and noticed the water barely beginning to steam below boiling. I'd say close to around 212 for a reasonable amount of time would clear up any condensation issues.

 

[mechtech2]

Originally Posted By: DinoOil
Originally Posted By: SteveSRT8
Note that you do not have to get anywhere near the boiling point of water to evaporate it out of your oil. 180 degrees is plenty hot if sustained for a few minutes. It's time versus temp and vapor pressure.


I'll tend to agree with you, however the vaporization may not be significant at such a low temperature relative to 212 deg F at 1 atm. We've all watched a pot of water heating up on the stove and noticed the water barely beginning to steam below boiling. I'd say close to around 212 for a reasonable amount of time would clear up any condensation issues.


You can't see steam. It is a gas. We CAN see condensed water vapor.

 

[DinoOil]

Diid you ever see gaseous Chlorine? How about Flourine? Gases with distinct colors and we can see them too.

We can see evidence of steam by its change of state back to liquid. However, what was the point in your little diversion?