engine oil temperature?

flash7210 · **Posted:** Fri Apr 14, 2017 3:56 pm

Anybody have a engine oil temp gauge?

Theres already been lots of discussions about coolant temperature.
But because the engine oil cooler is cooled by the engine coolant, I was wondering how much engine oil temp was effected by coolant temp.
Like, if you had a 195f thermostat, would your engine oil also be 195?
What is a good engine oil temperature?
Does engine oil temp really matter?

So I decided to do a simple test.
Conditions:
Engine fully warmed up after a 15 min drive home.
Ambient temp 81F.
Coolant temp 190f (as read with torquepro)
Vehicle parked in driveway, idling for about 5 minutes, while went in to find my temp probe.

I pressed my my temp probe up against the oil pan through a gap between the oil filter and pan.
Measured temp 185f

Ok, so maybe taking a measurement of the aluminum oil pan is not the best way to measure oil temp but its the best I could do with the tools I have.

What do you think?
Do these numbers make sense?

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

Proper regulation of engine oil temperature is just as critical as engine coolant temperature for long term reliability of the engine. Measuring engine oil temperature is a good way to monitor this. There is probably a spot somewhere on the engine block that has a plugged port to the oil gallery. That is where I would put a proper temperature sending unit, and have it hooked up to a high quality, accurate gauge that can give you a temperature reading in degrees.

Run an engine oil too hot, and you can get rapid breakdown of the oil's viscosity, burn-off of the additive package the oil contains and therefore severe impairment of the ability of the oil to properly to protect the engine.

Run an engine oil too cool, and you can get a build-up of acids and other contaminants from the pollution control system in the oil. This has been suspected as one of the reasons why the rocker arms in the CRD engine have prematurely worn in so many cases.

It is terrible that the CRD engine was saddled with such a bad pollution control system... running the engine cool to meet that ridiculous NOx standard we have here in North America makes all the bad things that happen to the CRD engine even worse because the engine has little opportunity to burn off any of that pollutant and acid build-up, both in the engine and in the oil. The colder the climate you live in, the worse the situation gets, because opportunities for the engine to get to a high enough operating temperature to do any good become few and far between.

With the advent of synthetic engine oils, overheating the oil is becoming less and less of a problem, because synthetic engine oils withstand higher operating temperatures reliably for a much longer period of time. The problem we have with the Liberty CRD engine is that the engine oil actually runs too cool most of the time. This is why, even for the standards of a normal diesel engine you see rapid build-up of contaminants in the CRD engine's oil, necessitating more frequent oil changes. It is for this reason I change my engine oil at least twice as often as recommended by the manufacturer, and I ALWAYS use synthetic engine oil in the proper weights, (0W-40 or 5W-40), that has an additive package that meets Chrysler's MS 10725 specification. This additive package no doubt has extra chemicals and detergents in it to help deal with the pollutants being pumped into the engine.

Because I do not have a Green Diesel Engineering tune in either of the family CRDs as of yet, I perform the following when I do an oil change...

1) Drain the old dirty oil out, but keep the oil filter in place.

2) Fill the oil sump with cheap DIESEL rated oil.

3) Operate the vehicle for about 100 miles.

4) Get the CRD back on ramps, and then add an engine flush. Run the flush with NO LOAD on the engine for the complete recommended time.

5) Drain out the engine oil again and then remove the oil filter as it has now been contaminated by the engine flush. Let everything drain for a while... go have a lunch, grab a beer and watch a little of the game; whatever.

6) Clean off the drain area and the filter port completely, re-install your drain plug, (or, close off the Fumoto Oil Valve you should already have on your oil pan), and install a fresh oil filter.

7) Fill with the recommended synthetic diesel rated oil that meets Chrysler's MS 10725 spec. For the record, AMSOIL has an oil that meets this spec, and is not too expensive.

If you want to extend your oil change intervals, do the following...

1) You need to either remove the pollution control systems, or install a GDE tune.

2) Install a bypass oil filter system, (AMSOIL and another manufacturer has these as well), and get your engine oil tested every 5000 miles.

joe_ · **Posted:** Fri Apr 14, 2017 8:34 pm

TURBO-DIESEL-FREAK wrote:

Measuring engine oil temperature is a good way to monitor this. There is probably a spot somewhere on the engine block that has a plugged port to the oil gallery. That is where I would put a proper temperature sending unit, and have it hooked up to a high quality, accurate gauge that can give you a temperature reading in degrees.

Conveniently, there are three ports like that on the engine block, below the exhaust manifold. (Actually there are four, but one is used as the turbo oil supply. The other three are plugged.)

Three of the ports (two of the plugged ones plus the turbo oil supply) are visible here, in the 9th image down: http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=98&t=74594 [[Edit: or just look at WWDiesel's post below]]

I've wanted to find a combined oil pressure/oil temperature gauge (sort of like this), but after searching around I'm convinced that doesn't exist.

WWDiesel · **Posted:** Fri Apr 14, 2017 8:47 pm

Installing a Week's Elbow Kit and / or an EGR Block Off Plate along with a DIY tune will accomplish the same results!

As to reading oil temperature, if you can put the thermal gun's dot on the oil cooler's outlet, it might be a more accurate reading.
There are also three plugs (see picture, hex plugs) on the passenger side of the block under the exhaust manifold on the main oil galley where a temperature probe for a gauge could be installed provided you can find the correct threaded adaptor...
Same oil galley as where the turbo gets its bearing lubrication from!

flash7210 · **Posted:** Fri Apr 14, 2017 8:50 pm

Quote:

The problem we have with the Liberty CRD engine is that the engine oil actually runs too cool most of the time.

But, how do you know this?
How does anybody know this?
Without some sort of a gauge, its really just an assumption.

Given that its a turbocharged engine and the oil is used to cool the pistons, I would expect oil temps to be quite high.

flash7210 · **Posted:** Fri Apr 14, 2017 8:55 pm

joe_ wrote:

TURBO-DIESEL-FREAK wrote:

Measuring engine oil temperature is a good way to monitor this. There is probably a spot somewhere on the engine block that has a plugged port to the oil gallery. That is where I would put a proper temperature sending unit, and have it hooked up to a high quality, accurate gauge that can give you a temperature reading in degrees.

There are three such ports on the engine block, below the exhaust manifold. (Actually there are four, but one is used as the turbo oil supply. The other three are plugged.)

Three of the ports (two of the plugged ones plus the turbo oil supply) are visible here, in the 9th image down: http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=98&t=74594

I've wanted to find a combined oil pressure/oil temperature gauge (sort of like this), but after searching around I'm convinced that doesn't exist.

Technically, all those ports are post-cooler.
Wouldnt it be better to monitor pre-cooler temps to know if the oil is reaching breakdown temperature?

WWDiesel · **Posted:** Fri Apr 14, 2017 11:26 pm

flash7210 wrote:

Quote:

The problem we have with the Liberty CRD engine is that the engine oil actually runs too cool most of the time.

But, how do you know this?
How does anybody know this?
Without some sort of a gauge, its really just an assumption.

Given that its a turbocharged engine and the oil is used to cool the pistons, I would expect oil temps to be quite high.

And the oil is lubricating and cooling the turbo bearing! You know it is picking up some heat there as well....

flash7210 wrote:

Technically, all those ports are post-cooler.
Wouldnt it be better to monitor pre-cooler temps to know if the oil is reaching breakdown temperature?

I would more interested in what the oil temperature is that is going to the bearings and the piston sprayers and that is oil AFTER it has left or been through the oil cooler, not before.
Pre-cooler oil temperature would be the same as the oil in the oil pan where the oil pump gets it suction...
You probably could drill and tap and install a temp probe in the oil pan if you wanted to know that temperature? I personally do not think it is relevant.

GordnadoCRD · **Posted:** Sat Apr 15, 2017 2:50 am

WWDiesel wrote:

And the oil is lubricating and cooling the turbo bearing! You know it is picking up some heat there as well....

True, and not just inside the turbo bearing housing.
If you follow the un-insulated steel line, it passes several inches of it's length within 1/4" of exhaust manifold and turbine housing, which is commonly 600+ degrees. That's a LOT of heat soak for the oil that passes through it, even before it gets to the bearing housing.

Since I hope to give the Sasquatch turbo every advantage I can to help it last, I pulled the supply line banjo bolt on the top end, and slid this stuff
https://www.amazon.com/Heatshield-Products-201012-Thermal-Sleeve/dp/B000QFQE2C/ref=sr_1_10_m?s=automotive&ie=UTF8&qid=1492237480&sr=1-10&keywords=heatshield%2Bproducts%2Bsleeve&th=1
around it all the way to the block fitting, cut to length, and put the bolt back in with 2 new copper washers.

I don't know how much radiant heat it will block, but it could be a few bucks well spent, or at worst, a few bucks wasted. Wouldn't be the first time that's happened though.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

flash7210 wrote:

Quote:

The problem we have with the Liberty CRD engine is that the engine oil actually runs too cool most of the time.

But, how do you know this?
How does anybody know this?
Without some sort of a gauge, its really just an assumption.

Given that its a turbocharged engine and the oil is used to cool the pistons, I would expect oil temps to be quite high.

Yes indeed, it is an assumption. But it is an assumption based on my experience with diesel engines and the very nature of the old school diesel engines verses these more modern diesel engines that have pollution control systems in them. I have a strong suspicion that the oil is below optimum temperature because running engine oils below optimum temperature contributes to contaminant build-up in the oil and of how quickly I have observed the engine oil gets dirty in a unmodified CRD engine.

An oil analysis of used CRD engine oil from a reputable laboratory would confirm this, as you would get different analysis results from oil run at different temperatures.

dh100m · **Posted:** Sat Apr 15, 2017 8:23 am

Most remote thermostatically controlled oil coolers fully open at 80c which is the normal operating temp of most modern oils

I am in the midst of fitting of fitting one in place of original cooler along with a few other mods
tony

flash7210 · **Posted:** Sat Apr 15, 2017 8:29 am

dh100m wrote:

Most remote thermostatically controlled oil coolers fully open at 80c which is the normal operating temp of most modern oils

I am in the midst of fitting of fitting one in place of original cooler along with a few other mods
tony

80c = 176f

I agree, most oil cooler thermostats are set to about 180f.
However, the oil cooler on the CRD engine does not have a thermostat.

One thing the coolant-to-oil cooler does is help the engine oil warm up quicker.
The coolant will warm up faster than the engine oil and some of that heat will get transferred to the oil.

WWDiesel · **Posted:** Sat Apr 15, 2017 11:48 am

Since the oil is being cooled by a liquid coolant heat exchanger, I suspect that you will find that the oil temperature is always going to be slightly higher than coolant temperature!
Liquid heat exchangers generally perform in the 80-90% efficiency range when new and degrade from there as tubes become fouled or coated and insulate the cooling surfaces.
The oil will never be at a lower temperature than the liquid medium cooling it!!!

Based on that, oil leaving the heat exchanger with a factory Mopar thermostat most likely will be ~190 degrees or slightly higher.
That is provided the oil cooler is working at peak efficiency and is fairly clean internally. [*(176 + 10%=193) (176 + 20%=211)]

If running a HDS unit with a higher (205) degree thermostat, the oil leaving the exchanger will most likely be up in the ~*225 or higher range.

But as some others have commented, only a temperature gauge would reveal the true data! :roll:

*based on oil heat exchanger efficiency factor!

:SOMBRERO:

Sergio del Castillo · **Posted:** Sat Apr 15, 2017 2:38 pm

The temperature of the engine oil should be at least 212F to boil away the water, cause of other contaminants, and not higher than 250F to avoid oil degradation.

Sorry about the misspells

lacabrera · **Posted:** Sat Apr 15, 2017 3:14 pm

I installed an oil temperature gauge some time ago. Under normal driving the gauge reads 76c under excessive hard driving/towing it can increase to 86c. Its nether run above the coolant temp.

joe_ · **Posted:** Sat Apr 15, 2017 3:41 pm

Interesting. Where did you install the probe for the temperature gauge?

WWDiesel · **Posted:** Sat Apr 15, 2017 8:45 pm

lacabrera wrote:

I installed an oil temperature gauge some time ago. Under normal driving the gauge reads 76c under excessive hard driving/towing it can increase to 86c. Its nether run above the coolant temp.

Nether of those temperatures are high enough to be of any concern for high temperatures... :roll:

tjkj2002 · **Posted:** Sun Apr 16, 2017 11:24 am

WWDiesel wrote:

Since the oil is being cooled by a liquid coolant heat exchanger, I suspect that you will find that the oil temperature is always going to be slightly higher than coolant temperature!
Liquid heat exchangers generally perform in the 80-90% efficiency range when new and degrade from there as tubes become fouled or coated and insulate the cooling surfaces.
The oil will never be at a lower temperature than the liquid medium cooling it!!!

Based on that, oil leaving the heat exchanger with a factory Mopar thermostat most likely will be ~190 degrees or slightly higher.
That is provided the oil cooler is working at peak efficiency and is fairly clean internally. [*(176 + 10%=193) (176 + 20%=211)]

If running a HDS unit with a higher (205) degree thermostat, the oil leaving the exchanger will most likely be up in the ~*225 or higher range.

But as some others have commented, only a temperature gauge would reveal the true data! :roll:

*based on oil heat exchanger efficiency factor!

:SOMBRERO:

If they designed the system correctly(doubt it being Italian) the oil cooler should be on the return side(coolant returning to the engine from the radiator) thus up to 30-40 degrees cooler then what the temp gauge is saying. Also why all the vehicles with a in-radiator trans cooler have that cooler on the return side.

The return side of the radiator should be 30-40 degrees below the inlet side,if not you have a poor performing cooling system and needs to be addressed ASAP.

joe_ · **Posted:** Sun Apr 16, 2017 12:24 pm

It looks like the oil cooler gets its coolant directly from the water pump housing, which is on the return side.

WWDiesel · **Posted:** Sun Apr 16, 2017 1:13 pm

tjkj2002 wrote:

If they designed the system correctly(doubt it being Italian) the oil cooler should be on the return side(coolant returning to the engine from the radiator) thus up to 30-40 degrees cooler then what the temp gauge is saying. Also why all the vehicles with a in-radiator trans cooler have that cooler on the return side.
The return side of the radiator should be 30-40 degrees below the inlet side,if not you have a poor performing cooling system and needs to be addressed ASAP.

I agree!

Best I can tell, I went and crawled up under Jeep and looked; the coolant flow entering the engine oil cooler is via the discharge of the engine water pump. So this would be after the coolant has passed through the radiator. Water pump gets its suction from the outlet side of the radiator. (long hose coming from left hand bottom side)
The engine water pump discharges directly into the engine block, and then onto the head and various other items; the oil cooler is bolted to the side of the engine block where a small portion of coolant is directed directly through the oil cooler from the engine block.
A small amount of coolant passes through the cooler absorbing/removing heat from the oil and is then routed right back into the water pump's suction. :shock:

The oil cooler has only one external pipe/hose, the inlet is mated to a small port/passage on the side of the block.

So basicly the coolant passing through the oil cooler is always flowing in a small circle somewhat to some extent, but at the same time is always being mixed with the lower temperature coolant coming back from the radiator before it is discharged back into the block to make another cycle. :shock:

Design does seem a little odd to me, but it apparently works ok and I hope the engineers took this into account when designing it.
If I were designing it, I would have routed the oil cooler coolant discharge back to the radiator inlet, thermostat housing, or radiator inlet piping somehow...that way it would not be adding heat to the incoming coolant before it enters the block.. :wink:

lacabrera · **Posted:** Sun Apr 16, 2017 2:47 pm

joe_ wrote:

Interesting. Where did you install the probe for the temperature gauge?

I removed one of the plugs that enter the main oil gallery with a metric to 1/8th bush for the sender unit. It was over a year ago seem to remember there is 2 plugs I used one for the oil pressure sender and the other for temp. An interesting thing is when I was running 5w-30 oil the oil temp was about 10c higher switching back to 5w-40 lowered its temp and added a couple extra psi pressure on tick over.

engine oil temperature?

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