Oil/Coolant Separation Test

[Spooner65]

Recently, on another forum, some questions were raised about oils and coolants mixing if a head gasket or oil cooler failed. So I put some to the test, and thought I would post the results here as well.

From left to right they are Shell Rotella T6, Shell Rotella T, Mobil Delvac, Amsoil DME, and a control to show color, transparency, and amount of coolant in each bottle.

Immediately after mixing:

12 hours later:

24 hours later

48 hours later:

 

[Jim Allen]

Very interesting. Not a topic discussed here much. Please tell us more about the coolant used (type and mix w/water) and the control (which I assume to be the bottle on the right). Best separation from the Amsoil and T6. Worst with the Delvac.

 

[justinf89]

Wow a cool test indeed. Thank you for taking the time. I wonder if different types of coolants would make any difference?

 

[The motor guy]

interesting how the amsoil one doesn't look any different.

 

[Spooner65]

The coolant used was a CAT-1 rated ELC "Chevron DELO", a common coolant for diesel users, especially the 7.3L from Ford.

It was a 50/50 ratio of concentrate coolant and distilled water, exactly what you would find in a typical cooling system.

The bottle on the far right is indeed the control. It show the amount, color, and transparency of the coolant present in each bottle so you can compare separation levels. Look how close the Amsoil is to the control.

The reason this is important is because if you have a head gasket or oil cooler failure and you get the "milkshake" it can be incredibly hard to get out of your system. An oil that separates well allows you to drain off most coolant then flush the system. It's only one small characteristic of the oil, but an important one if things go south.

 

[Spooner65]

http://www.youtube.com/watch?v=1-IhRTZit0E

This is a video of the first 10 minutes of the test. What is interesting is both the Rotella T and Amsoil IMMEDIATELY separate either water or coolant. You can see a distinct line form at the exact level that served as the 1/2 mark for the 50/50 solution. So either all of the water or all of the coolant separated right away.

 

[Jim Allen]

Wow. I gotta get a life. Sitting here watching videos of oil and coolant separating ( : < )

Thanks for posting. Not sure what any of this means. Interesting to note that both the syn oils (one PAO and one Gp III) separated the most completely in 48 hours. My anecdotal experience is that eventually even emulsified oil will separate but I never timed the event. Days, certainly. If there is a big difference in this performance, it would have to be regarded as a very minor plus or minus point when evaluating an oil for use in an engine. Well, unless you owned a 6.0L ( : < )!

 

[Garak]

Yes, Jim, that's what I'm trying to get my head around. Obviously, things will separate eventually, but from a lubrication perspective, is it better for a rapid or a slow separation? Each have their points, obviously. If I had a rather high volume of coolant dump into my sump, I wouldn't want it separating rapidly. I don't think it would be good to be pumping a bunch of relatively pure coolant/water. On the other hand, if it were a tiny amount and it stayed in the bottom of the pan, great.

 

[Spooner65]

Originally Posted By: Garak
Yes, Jim, that's what I'm trying to get my head around. Obviously, things will separate eventually, but from a lubrication perspective, is it better for a rapid or a slow separation? Each have their points, obviously. If I had a rather high volume of coolant dump into my sump, I wouldn't want it separating rapidly. I don't think it would be good to be pumping a bunch of relatively pure coolant/water. On the other hand, if it were a tiny amount and it stayed in the bottom of the pan, great.


As long as the engine is on, it will not separate. It will continually circulate and mix.

As mentioned, this is a VERY small characteristic of any oil, but a nice one if one should find them with a milk shake.

 

[Garak]

Originally Posted By: Spooner65
As long as the engine is on, it will not separate. It will continually circulate and mix.


I agree. I was thinking about starting an engine after there was coolant intrusion and someone foolishly didn't change the oil beforehand.

 

[Silk]

I've doing a similar test with the oil out of the compressor at work. The oil in it is always completely emulsified, and I change it every 3 months. I've never seen a compressor do this before, and I used to work on them for a living.

After a week there is a thin line of oil at the top....I reckon months to separate.

 

[Spooner65]

Is the compressor water cooled?

 

[skyship]

Great test and clip, BUT the engine would have been toast in bearing damage terms regardless of oil type.
Next time can you do a few more oils like Castrol Edge and Mobil 1 ??, also if you heat them up to near boiling point and then use a blender for a while to better simulate a real engine. You might have to borrow a few stoves and blenders, so don't tell your friends what you are doing with them!

 

[Shannow]

Oils are made to either keep emulsions, or break them.

An R and O 32 turbine oil is constantly pelted with steam, heated to 80-100C, and then cooled to low-mid 40s C.

It drops water amazingly.

Other lubes are made to hold water.