Oil Temperature Discussion

[flint54]

If given that higher oil temperatures equate to less viscosity, and possibly greater wear rates, it seems

that having some grip on actual oil temp could be helpful. Is anyone here actual measuring oil temp with

an added gauge? If yes, what do you nominally read? I understand that the API ratings take into account

the service temperatures, and understand that there's a tradeoff if oil temps are too low (cannot deal with

moisture), but also know that a number of vehicles do measure oil temps. In a hard working engine (like

pulling a heavy load), it seems there could be advantage in measuring and controlling oil temps. Comments?

[Jeep Driver]

I'm more concern with coolant temps.

 

New radiator and full-time electric fan.........temp never leaves 190 degrees no matter how hot the ambient temp is or how long at idle or interstate driving.

 

I'll let the oil take care of itself.

[Jeep Driver]

BTW I've moved to Havoline 20-50 in the 2.5 with Napa Gold filters. 2.5 has about 9K miles on it now and oil pressure at idle is never less than 40lbs and at 2000rpm is generally at 58lbs. I have found Havoline to be pretty stable between changes.

 

In the 4.0 I'm using Havoline 40w with Lucas treatment to maintain acceptable oil pressures. Most the 4.0s I encounter are high mileage.

[flint54]

Certainly coolant temps get all the glory and attention, and shouldn't be ignored,

but I continue to believe that oil temps could be a far more reliable indicator of

what is going on at the most critical and highest stress points inside, the rotating

and sliding surfaces where heat management is of the utmost importance, second

only to minimizing contamination. Anyways, I appreciate your reply. This topic

didn't generate the interest I had hoped for. Last call - any of you folks measuring

your oil temperature? Somebody has got to step up to the plate and help me

justify yet another add-on for this truck: http://www.hesco.us/shop.asp?action=det ... catId=7936

Please?

[mvusse]

I have never owned a driven a vehicle with an oil temp gauge. Closest was a transmission temp gauge on a 4wd K30 I drove for a summer. Don't know of any that came from the factory with one either.

 

A lot of heavy duty vehicles set up for towing (pickup trucks, large SUVs, some vans) have a factory oil cooler either inside the radiator, separate from the radiator, or both. My Suburban for example used to have one in front of the A/C condenser, followed by one inside the radiator. I believe the thinking behind running it through the radiator after the primary cooler was to prevent the oil from getting too cold in the winter -> higher viscosity/higher fuel consumption.

[Garvin]

Didn't think I was going to see a thread this deep on CC. :clapping:

 

While oil temp is important to the wear and tear on the inside of the engine, most manufacturers (hoping all at this point) take that into account with the recommended oil for the vehicle. Engine oil has a lot of wiggle room with temperature, unlike transmission fluid, which is why the heavier trucks have the transmission temp gauge. The engine oil is supposed to stay within spec to work while the engine is within the normal operating temperature. For the 4.0's, between 190 and 210 in the coolant is where the optimum temp is for the oil to be most effective. I have seen many external oil coolers (many of which are on turbo'd vehicles) but very rarely see one that's inside the radiator. Usually the radiator one is dedicated for the transmission fluid as that needs to be regulated a lot more.

 

The "warmer" aspect of that Hesco setup is kinda of pointless, atleast the way I see it. The coolant and oil warm up about the same, if not the oil warming up faster due to all of the oil being gone through (coolant only swaps out on startup when the engine gets up to temp, then cold coolant comes in, oil gets warmed up at the same speed to temp but all of it gets warm at the same time). Unless you really plan on doing a lot of towing, I wouldn't worry about the cooling aspect. I wheeled my old Cherokee hard (first on stock 3.55's and 36's then went up to 4.56's with the same 36's) and never had an oil cooler. Never once did I have oil issues.

 

The key aspect to all of this is to make sure your coolant system is running correctly and optimally. The coolant regulates the engine, which in turn, regulates the oil to the correct temperature. Also make sure that your oil is filled as the oil in the sump also cools down the returning oil some helping to keep it regulated better.

[flint54]

"Don't know of any that came from the factory with one either."

 

Granted there aren't many, but some: GT40, 911S, M3, CTS-V, and other mundane cars...

 

I'll let this one go as just another momentary automotive infatuation. They pass quickly.

 

Now back to your regular programming..........

;)

[mvusse]

"Don't know of any that came from the factory with one either."

 

Granted there aren't many, but some: GT40, 911S, M3, CTS-V, and other mundane cars...

 

I'll let this one go as just another momentary automotive infatuation. They pass quickly.

 

Now back to your regular programming..........

;)

 

:doh:

 

I did know about the M3 having an oil temp gauge.. Just didn't remember it.

[jimoshel]

Oil temp gauge on passenger cars and light duty trucks impress the tourists but are unnecessary to the operation of the vehicle. Just watch the coolant temp. When operating a aircraft I won't even start the take off roll until the oil temp gauge reads at least half way but that is a different situation.

[flint54]

Depending on your confidence level, all gauges are unnecesasry to the operation of the vehicle.

[HOrnbrod]

Speaking vehicles, not aircraft (an entirely different ballgame), the two most important gauges I watch to avoid catastrophic failure are the the oil pressure and temp gauges. The tach and speedo you "feel" rather than watch, and I look at only when I suspect the law might be watching. :D The third gauge I monitor most is the A/F meter that gives the best statement of engine health. A high oil temp is normally immediately followed by a rise of the coolant temp gauge, so I think it's not really needed. I do have an two-pod "A" pillar pod where the A/F meter now resides. In it will soon be either a tranny fluid temp gauge, or a vacuum gauge. Since I don't do all that much towing and I have a tranny oil cooler that works well, I'm leaning toward an old school vacuum gauge. It will compliment the A/F meter nicely.

 

[Jeep Driver]

Years ago I lost an engine due to loss of oil pressure. Temp and oil pressure gauges are important.

 

I had a Dodge with a slant6 who's oil pressure sender broke and I lost all oil in about a 1/2 mile.........had I paid attention.......

 

 

 

Really has nothing to do with confidence.

 

 

Now that I have a 5 speed vs the 4.0 with auto I suspect the heat created in the auto-trans contributes to the 4.0s running hot. I noticed that the temp will rise during a long haul up grade on the mountains round here. My next 4.0 keeper will likely get a trans cooler........and maybe a temp gauge.

[jimoshel]

Ever notice that air cooled engines are more likely to have a oil temp gauge than a liquid cooled ones? Not really sure if they do or not but the discussion was slowing down so just stirring it up a little. :yes:

[zagscrawler]

IMHO having an oil temp gauge is a great idea... Me being a mechanic I allways pay attention to all the important temps, for example when i have spent tons of time and money (well my bosses money) rebuilding a high strung racing engine with oil clearances in the .002-.004 of an inch it is EXTREMLY important to warm up the oil to proper temps before you go sticking your foot in it. In my shop we have a few body guys that don't appreciate the importance of proper warm ups and just start it up and hit the rev limiter when they need to move the car around. The gauge allows anyone to get into the car and know when its ok to put the car into loaded environments, well atleast i always warn them to let it warm up a bit and know they can acctually see with there own eyes when it is safe. Also the way i see it is the water temp is no where near as consistant as oil temps and i think it to be in bad form to assume they will heat up the same. The water is mostly heated up from the water jackets surounding the bores and porting around the combustion chambers which generate TONS more heat than the frictions and viscositys of the oil and bearings. So to get back to the original question I wouldn't hesatate to install an aftermarket oil temp gauge in my jeep, cold starts (which is very difficult to avoid) and loading the engine before the oil warms up is the leading cause in bearing wear hands down.

[jeepcoma]

Certainly coolant temps get all the glory and attention, and shouldn't be ignored,

but I continue to believe that oil temps could be a far more reliable indicator of

what is going on at the most critical and highest stress points inside

 

I think you're right, but with oil it's more of a long term wear situation rather than a warped head or critical seizure like would happen with too high coolant temps. If oil overheats, sure it will wear out faster and accelerate engine wear, but your oil selection and change interval should be taking care of that before the oil wearing out (and by that I mean, all the additives are consumed). If you know you'll be operating in a severe manner, adjust your viscosity and change the oil more frequently to suit; essentially, pre-emptive maintenance.

 

I think also that oil pressure is a pretty good indirect indicator of both temperature and flow, that a separate temp gauge isn't needed for most vehicles. It's very easy to know what's going on with the oil by reading the pressure and knowing how it should be behaving and determining if you have an issue. When I cold start in the morning, I can tell when the oil starts to warm up by the idle pressure. When I'm cruising on the highway, I can see when everything is finally up to temp (which, by the way, I have noticed the oil takes FAR longer to reach final temps than coolant). When I'm stuck in traffic in the boiling heat I keep an eye on the pressure to see if it starts dropping too low. And of course if it ever suddenly just drops to 0, I've got a flow problem!

 

So while I may not know the exact temp, it's enough to know whether or not I'm in the danger zone. I think many (most?) new cars incorporate oil temperatures into the computer for the benefit of the "oil change interval" suggestion. With fancy 15k mile oil change intervals it's much more important to know the status of the oil, and the computer keeping track precisely of the temperatures can accurately measure when it's time to change. In lieu of calculating, the rule of thumb is just "change early, change often" which leads to increased cost and unnecessary waste (rather, it would be unnecessary if you knew a change wasn't required).

 

That's my take on it anyway. +1 on the vacuum gauge, it's the most informative gauge never used anymore. There's so much to learn from a vacuum gauge, but it seems like a lost art though. People rely so much on the computers they overlook the simple tools, but there's a ton of information to learn from vacuum. Coolant temp, oil pressure, and vacuum really tell you just about everything you'd want to know (well, maybe gas).