EP gear oil operating temperature

[julianf]

I did a multi hour drive yesterday, and, when I got back, held my hand on the transfer box (ep90) and the gearbox (mtf94).

I say "held" but the ep90 box invoked an involuntary reflex pull back.

The mtf94 box was too hot to hold a hand on, but not the same "jerk" response.


The ep90 box did not hiss my hand, so it's not like it was over 100c but certainly I'd estimate over 75.




My question (and the reason I'm asking here rather than car forums) -

What is considered the ideal temperature ranges for these sorts of oils?


You can fit cooling devices, but I don't know if that would make things better or worse.

Thank you.

 

[hotponyshoes]

I have no idea about the oil, but I'd think you were over estimating the temperature.

One 'standard' is that 60⁰c is safe to touch for 5 seconds. That will hurt but won't do damage.
Metal transfers heat into skin easily so feels hotter than it is.

Cheap cooking oil won't start smoking until 200⁰+ so I wouldn't be worried about gear oil if I was using the correct grade at the recommended service intervals.

If you use the vehicle outside of 'normal' operating conditions maybe a cooler would be good but I'd also want a thermostat as you'll do just as much damage running too cold.
Maybe start with finding a way of confirming the temp reading? Pull the filler plug and pop a probe into the oil?

 

[julianf]

I was comparing with touching the head, which is a known temp (84c)

The ep90 box was a similar pain level. The mtf94 box was less.

I think my calibration, although rough, is in the right ball park with regards to numbers.

 

[hotponyshoes]

I've got a bottle here that says maximum operation temperature is 150⁰c.
It also says store below 60c so maybe it starts to degrade above that (or maybe the container will melt)

 

[reb78]

I dont know the answer to the oil question but a load of folk on lr4x4 were running these (or similar) on their gearboxes - https://uk.rs-online.com/web/p/temperature-sensitive-labels/7799772

Might give a good idea of the temps you are seeing

Running temps seemed to be around 85C on the transfer boxes with a cooler for reference (although the one i found just now was behind a V8).

 

[E T]

I did a multi hour drive yesterday, and, when I got back, held my hand on the transfer box (ep90) and the gearbox (mtf94).

I say "held" but the ep90 box invoked an involuntary reflex pull back.

The mtf94 box was too hot to hold a hand on, but not the same "jerk" response.


The ep90 box did not hiss my hand, so it's not like it was over 100c but certainly I'd estimate over 75.




My question (and the reason I'm asking here rather than car forums) -

What is considered the ideal temperature ranges for these sorts of oils?


You can fit cooling devices, but I don't know if that would make things better or worse.

Thank you.

LandRover I presume?
I used to check the temps in the gearboxes very regularly with a temp gun and 70°+C was quite normal for the transferboxes. On very hot days even more.
The oil should have no problems handeling up 120°C if I recall correctly. Check the container, it should be on there. Or check google for the specs.

 

[OJCar]

From Castrol's EP90 Product Data Sheet
https://msdspds.castrol.com/bpglis/...2B8B3C7802579FA002E89AC/$File/BPXE-8U75DA.pdf

"Flash Point 190C"

From Morris's EP90 SDS
https://safety365.sevron.co.uk/substances/accessSDS/SDS-546-568cb5e179ca37.15400656

"Boiling Point >320C"

So an estimated 75C to 100C is not going to trouble the oil.

 

[Kayos]

I could always tell the Disco had flushed it's transfer oil, ready for a refill (great bit of automation by LR) when the tunnel was cooler after a long run

 

[hotponyshoes]

I could always tell the Disco had flushed it's transfer oil, ready for a refill (great bit of automation by LR) when the tunnel was cooler after a long run

I've changed the auto box oil on various land/Range rovers. The gearbox casing as to be at a certain temperature when you check the level. I don't remember what exactly but it was pretty low. Certainly nothing like the numbers mentioned above?

Maybe the temp for checking is not the same as the running temp though?

 

[Erie Fred]

The contactless "laser pointer" temp devices are very inexpensive,
and will put an end to "hot" "too hot" "Ouchy Hot" controversy.

 

[julianf]

The contactless "laser pointer" temp devices are very inexpensive,
and will put an end to "hot" "too hot" "Ouchy Hot" controversy.

They dont work well on silver surfaces though. Neither does my sharpie.

I dont even know why this is, as, i assume, they just receive IR - i know mylar sheets etc are used as insulation, but you wouldnt have thought that it would make that much difference at this level, but it does seem to.

 

[Erie Fred]

They dont work well on silver surfaces though. Neither does my sharpie.

I dont even know why this is, as, i assume, they just receive IR - i know mylar sheets etc are used as insulation, but you wouldnt have thought that it would make that much difference at this level, but it does seem to.

So temp's will be determined by feel alone........Pleaes carry on.

 

[julianf]

So temp's will be determined by feel alone........Pleaes carry on.

I have a laser thing. It does not work on silver objects.

In fact, i have two laser things. Neither work well on silver objects.


Remember, my question was on oil temperatures. Not on how to measure temperatures.

My question remains, irrespective of the method of temperature measurement.



Maybe we should have another thread on temperature measurement, and this one can be left to the original question?

 

[voipio]

They dont work well on silver surfaces though. Neither does my sharpie.

I dont even know why this is, as, i assume, they just receive IR - i know mylar sheets etc are used as insulation, but you wouldnt have thought that it would make that much difference at this level, but it does seem to.

The emissivity of non-oxidised metal surfaces is generally very low e.g. for polished aluminium the figure is ~0.095, and gold is 0.02, so well below the "normal" 0.95 emissivity value used for the calibration of the point and shoot type infrared thermometers. It is also the reason why arty installations of stainless steel spheres can actually get quite hot in bright sunlight, because the absorptivity of stainless steel is quite a bit higher than its emissivity. Looking at a clean metal surface with a thermal imaging camera reveals that it behaves like quite a good mirror for thermal radiation, tending to give readings for whatever is being reflected. The same is true for copper pipework, making it difficult to monitor copper plumbing temperatures. A piece of black insulating tape (other colours will work quite well, too), can be used as a good measurement surface to point an infrared thermometer at. Becaus of its thinness, the surface temperature of the insulating tape is near enough the same as the temperature of the object it's affixed to.

 

[badabec]

Hello, most data sheets have no information on maximum temperature. This company states theirs is good for 150 C

EP90 - Selso Lubricants

Selso EP90 Gear Oil is a mineral based extreme pressure (EP) automotive hypoid gear oil designed to heavy duty, severe service. EP90 gear oil provides superior resistance to high temperature breakdown. Maximum operation conditions approach 150 degree Celsius.

www.selso.com.my

 

[PhillipM]

From Castrol's EP90 Product Data Sheet
https://msdspds.castrol.com/bpglis/...2B8B3C7802579FA002E89AC/$File/BPXE-8U75DA.pdf

"Flash Point 190C"

From Morris's EP90 SDS
https://safety365.sevron.co.uk/substances/accessSDS/SDS-546-568cb5e179ca37.15400656

"Boiling Point >320C"

So an estimated 75C to 100C is not going to trouble the oil.

The oil will begin to break down under the shear loads well before then.

100-120c bulk temps is generally considered safe maximums, depending where you're measuring (temps in the bearings exceed the sump temps you're usually measuring considerably), also depends on the oil, I'd be on the lower end of that for a cheap mineral EP90.

 

[OJCar]

The oil will begin to break down under the shear loads well before then.

100-120c bulk temps is generally considered safe maximums, depending where you're measuring (temps in the bearings exceed the sump temps you're usually measuring considerably), also depends on the oil, I'd be on the lower end of that for a cheap mineral EP90.

So an estimated 75C to 100C is not going to trouble the oil.

I stand by what I wrote.

 

[PhillipM]

Maybe, but quoting the flash point and boiling point as if they were relevant is a bit misleading when it comes to gearbox and engine oils.

 

[bricol]

The contactless "laser pointer" temp devices are very inexpensive,
and will put an end to "hot" "too hot" "Ouchy Hot" controversy.

Just remember the red dot isn't necessarily where the temp sensor is "looking".

Measuring some bearings on a machine in Olympia, I was caught out by the dot being on the nice black bearing housing (good for decent temp measurement) but the actual sensor was telling me the temp of the mesh guard a foot in front of me.

 

[OJCar]

Maybe, but quoting the flash point and boiling point as if they were relevant is a bit misleading when it comes to gearbox and engine oils.

Could you produce some authoritative data of the working temperature range of EP90 ?

As apparently my estimate from available data is not good enough.