With and without UOA's

[gfh77665]

Hypothetically, consider two average vehicles, driven in the exact same manner. One has regular UOA's, and maintenance is done exactly by the UOA directives. The other never gets a UOA, but follows the general consensus of OC's with conventionals at 5000, syn blends at 7500 or full syns at 10K.

Would either last longer? Which would have the greater expenses over a long time period, like 10-15 years?

 

[BMWTurboDzl]

The presence of a UOA has no bearing on engine life. It simply boils down to how much $$ you want to spend on repairs/maintenance. A vehicle which has a history of UOAs may give you notice of a potential problem which if addressed sooner rather than later may save you $$.


UOA on passenger cars is somewhat silly because the cost of an oil change is so low and engine failure is rarely the reason for someone dumping a car.

 

[Wilhelm_D]

Originally Posted By: gfh77665
Hypothetically, consider two average vehicles, driven in the exact same manner. One has regular UOA's, and maintenance is done exactly by the UOA directives. The other never gets a UOA, but follows the general consensus of OC's with conventionals at 5000, syn blends at 7500 or full syns at 10K.

Would either last longer? Which would have the greater expenses over a long time period, like 10-15 years?


That is really dependent on the vehicle, driving conditions, and other circumstances.

Assumption 1:

Vehicle is driven under severely adverse conditions - the guestimate schedule will be too low and the vehicle will have accelerated wear following it.

Assumption 2:

Vehicle is driven under optimum conditions - the guestimate schedule will be too strict and money will be wasted on unnecessary maintenance.

Assumption 3:

Vehicle is driven under average conditions, but a mechancial problem which would have been detected by oil analysis is unchecked. This leads to premature failure.

In other words, it all depends.

 

[gfh77665]

Thats why I stressed "average" vehicles & conditions.

 

[HTSS_TR]

My 1994 LS400 with more than 350k miles has these OCI's without any UOA: 6-8k/6mo with conventional oil and low to mid-price oil filter 12 mo, 12-16k/12mo with synthetic oil and the same oil filter.

The engine is running well without oil related problems, but other parts of the car are falling apart.

 

[gregk24]

UOA is a good tool to see how the engine oil is holding up, as well as seeing how much fuel or water is present in the oil. They can give some indication of wear as well, but you sure do save a lot of $$ by not doing them all together. You could use that $$ on an extra oil change for peace of mind. I have done two UOA before, both on different 5w20 synthetics. I may do one more just to make sure the TGMO 0w20 is doing a good job at protecting the Accord from all the short tripping it sees. If it comes back good then I wont be doing any UOA anytime soon.

 

[bigjl]

Never had a UOA done on a vehicle in my life

Don't know anybody that has

In the UK the only time they are done by dealers is when an engine was to seize when under warranty and they wanted to make sure it had oil in the sump at the time and wasn't topped up after the seizure

From what I have seen there a three main kinds of owner in the UK

The one who thinks the annual MOT is all a car needs and a service is topping up the oil just before the annual MOT

Those who buy a vehicle and service it pretty much to the schedule


And those who service to the schedule and also do an interim change at half way to ensure long engine life

At certain points of my driving career I have fitted in each category

UOA are likely fairly common in heavy haulage fleets

I am interested in how different oils deals with different usage though and I have several samples to send off to Blackstone

One thing I don't think is that any vehicle that I have looked after properly has been negatively affected due to a lack of UOA

But then I have mostly used either semi or full synth over the past 15/16 yrs with one two occasions using synth blend (10w40 Maxlife Diesel)

I don't remember ever using mineral/dino oil except in my 1966 Austin A40 back in '88 when I was in Uni.

Never had any kind of engine failure yet, even though I was a courier/private hire driver for 5/6 yrs back in the '90s prior to joining the Ambulance Service.

I have no qualms running an oil up to 10k without UOA within a year, though I have only very rarely left oil in for more than 12 months and it would normally be changed pretty soon after the year was up anyway

 

[bigjl]

Originally Posted By: HTSS_TR
My 1994 LS400 with more than 350k miles has these OCI's without any UOA: 6-8k/6mo with conventional oil and low to mid-price oil filter 12 mo, 12-16k/12mo with synthetic oil and the same oil filter.

The engine is running well without oil related problems, but other parts of the car are falling apart.


Is it even possible to break the engine in an LS400?

One of the most over engineered cars ever that one

Electrical gremlins will kill it years before the engine gives issues

The only reason they didn't sell well in the UK is simply fuel price related

 

[DuckRyder]

I think the question is basically impossible to answer as asked...

And my brain keeps saying "what is the real question" - I think the real question is "are UOA's worth it"...

To attempt an answer the original question my opinion is "probably a wash"...

But what exactly are we talking about, are we considering sampling mid OCI to determine interval? Will sampling continue even when a reasonable pattern has been determined and a more fixed OCI could be set...? What exactly do we mean by "UOA directives"?

I'm sure I'm not about to make any friends here (assuming I have any left) but I just don't think the average consumer UOA on a passenger car has much value past entertainment value... There are at least a couple of UOA's here on blown up motors that look OK...But if one does catch something, then you might be ahead of the game.

For stuff with huge sumps or fleets of similar vehicles/usage (and probably bulk UOA pricing) it makes more sense to me.

IMO/YMMV and all that...flame suit on...

 

[KCJeep]

A UOA on a passenger vehicle can be useful. Detecting coolant contamination early if it occurs can definitely have an effect on the longevity of the vehicle.

In the case of my Jeep a UOA every once in a while doesn't hurt as previous years had real troubles with piston skirts, sky high aluminum would be a good warning to do something BEFORE the engine grenades.

However in the absence of any major detectable problems I doubt longevity between your two hypothetical vehicles would vary at all.

 

[gfh77665]

Originally Posted By: DuckRyder

But what exactly are we talking about, are we considering sampling mid OCI to determine interval? Will sampling continue even when a reasonable pattern has been determined and a more fixed OCI could be set...? What exactly do we mean by "UOA directives"?


I dunno if "directives" is the correct word there, but usually they say things like "Run another 2500 miles and resample" or "this oil could go out to 9500 miles", etc. Maybe the word is "advisements".

I didn't mean to get bogged down in semantics here.

 

[DuckRyder]

OK.

 

[Quattro Pete]

Originally Posted By: DuckRyder
I think the question is basically impossible to answer as asked...

+1

 

[Kuato]

Originally Posted By: gfh77665
Hypothetically, consider two average vehicles, driven in the exact same manner. One has regular UOA's, and maintenance is done exactly by the UOA directives. The other never gets a UOA, but follows the general consensus of OC's with conventionals at 5000, syn blends at 7500 or full syns at 10K.

Would either last longer? Which would have the greater expenses over a long time period, like 10-15 years?


Short answer:
The non UOA vehicle would have somewhat higher expenses, due to not taking the oil to the maximum OCI, and possible depletion of additives resulting in more rapid wear, if the oil was taken beyond its capability.


Long answer:

Assuming that the same oil is used in both cases (to avoid any argument about one oil protecting better than another), I have to agree with Wilhelm_D. Taking an oil to its maximum distance would minimize cost, and wear would only increase if the oil was run too far and depleted of additives.

You can also throw in the discussion of too-frequent oil changes, which by some indicators increases wear.

All in all, a UOA is a great tool to indicate how far you can safely go with your vehicle/engine, driving style, and oil choice, in order to maximize your OCI. It can also give warning of issues with an engine prior to a catastrophic problem, which is why oil testing is performed on many commercial aircraft.

Usually the manufacturer's OCI takes everything into account so the average motorist (who doesn't have the tendencies of a BITOGer) won't have to worry about oil related failures; I would speculate the manufacturer also allows for lesser oils, which is why many can safely go beyond the OCI in the owner's manual with a UOA.