How about considering these factors for lube oil change?

1) Goal based limits
Parameter: Caution to Critical
Cleanliness 14/11 16/13
Wtr content 0.3% 0.5%
TAN 0.2 0.4
Fuel 1.5% 5%
Glycol 200ppm 400ppm
Soot 2% 5%
Flash point Drop of 30o Drop of 50o

2) Ageing limits
Parameter: Caution to Critical
Viscosity +/- 5% +/- 10%
RBOT -30% -60%
FTIR-Ox 0.3 1.0
Zinc -15% -20%
Calcium -10% -20%
TBN -50% -75%

And change the oil when any of the factors gets out of its specific limit?

How much costs get an analysis of all those parameters? How often to be tested? vs How much costs the oil change?

Does it cost more to monitor than to the potential save in oil change?

This message has been edited. Last edited by: Eugene,

Hm.. that would make the Skoda cost the equivalent of a Rolls Royce if they had to build all these sensors in the carter pan.
Probably the would have to put a mini Foxboro DCS on the dashboard. Talking about rocket science in the automobile industry

Sorry, I posted those parameters for big machineries like diesel engine, turbines & compressors where the lube oil capacity ranges from several hundreds to several thousands litres. How do you decide lube oil change at your plants?

For small machines like cars, pumps ect, time or meter-based, whichever comes first without oil analysis.

Josh for the big machinery (2 drums or 400 liter and up)following the OEM instructions gives less headache, and probably there is some Tribology support available.
For a gearbox that takes 2 liters of SAE 90 every 6 months, taking monthly oil samples and sending to analyze for $12- $15 a sample (without calculating that somebody has to be paid to take the sample, ship it, administration etc.), lube oil analysis would be gross overkill.

Are those listed parameters far off from OEM's instructions? Can they become a guideline?

All good points. Now I re-read the e-mail Skoda sent me, I think they actually take the time it takes to cool down from full operating temperature, (presumably the heating time would be dependent on how late I was for work!)

Might be a useful test in small industrial gearboxes/lube tanks, as it would be pretty cheap to organise. Suppose though it would have be one that stopped reasonably often, and was fully warm before stopping.

Still, as all the posts above are alluding to, it's a horses-for-courses situation, and I could think of a few situations this would be useful......

I'm changing jobs in a few weeks, so my Skoda is going back, I'm going to miss the Czech Flyer

This message has been edited. Last edited by: tthew,

Has anyone ever used a simple comparative patch test to check if their motor oil needs changing?

For years I have used a very simple and low cost kit called "Circoil" by Herguth Labs to check if my oil needed a change. I found that each vehicle I owned had different conditions and the oil changes were required at certain intervals.

Wife's Olds Cutlass didn't need a change until 5000 mi. early in its life. Now it needs it at about 4000.

Toyota Tundra needs a change between 5000 and 5500 mi.

Toyota MR2 Turbo needs a change at 3500-4000 mi.

Old sportscar with twin weber carburetors needs oil changed at 3000 mi. Sooner if I run a track day and can smell fuel in the oil when I'm home.

Keep a clean air filter, crankcase breather. Change your oil on condition based on the vehicle needs and use.

The new conventional oils seem to work just as well as the synthetics, particularly on camshafts, lifters and cylinder bores (no ridge in the cylinder bores at 170K mi). I do not change oil on a longer interval if I am using synthetic. Soot and dirt don't know the difference.

Regards,
Dan

quote:

Originally posted by svanels:
Josh for the big machinery (2 drums or 400 liter and up)following the OEM instructions gives less headache, and probably there is some Tribology support available.
For a gearbox that takes 2 liters of SAE 90 every 6 months, taking monthly oil samples and sending to analyze for $12- $15 a sample (without calculating that somebody has to be paid to take the sample, ship it, administration etc.), lube oil analysis would be gross overkill.

Any cut off volume of lube oil above which oil analysis is necessary? Eg above 230 litres or 30 litres?

If the 30 liters are from a gearbox, that can stop the production line, and put all the phones in the plant hot and ringing, I would take a sample at least bi-weekly.
If I have to lose my job, than it must be for something important not because of a miserable $5 oil seal or a few liters of lubricating oil.

In maintenance we have to look at the consequences of a failure and adapt our strategy according to that.

Counting failures is good, preventing them is what will distinguish the professionals

Given the consequencies the order to replace the miserable $5 oil seal get top priority at any plant.

If you wait until you feel the grit and dirt that has built up before you change your oil, A lot of damage has been done by that very grit that you talk about. It all depends on what you expect out of your vehicle. How long do you want the vehicle to last? Me..I want mine to become a classid. I expect to keep my Super duty Econoline E350 with a 7.3 L diesel for the rest of my life. SO I outfitted it a bypass oil filtration system. and use oil analysis to tell me when my oil needs a change.

DAn What brand of oil were you using for your samples? you mentioned synthetics...WHat synthetic brand of oil have you used?

Oil is change not upon the number of miles the car had been running but by the number of contaminants the oil have. When oil gets contaminated it becomes acidic. Try to check your oils TAN and TBN and this would be a better option than changing oil on a time-dominated frequency