What is the value of a UOA?

[D189379]

Can you actually determine if one oil brand/grade causes more wear than another?

Or does it tell you which brand/grade keeps more wear metals/ contaminants in suspension?

Or which brand/grade cleans the engine better?

Or none of the above? Maybe they're just useless?

 

[Quattro Pete]

This question is being asked a lot lately. Rather than repeat myself, I'll just post links to a couple of my recent responses on the subject. Others may chime in and provide their own commentary...

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2336521#Post2336521

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2336543#Post2336543

 

[ahoier]

I like the idea particularly, of seeing if there's AF/Coolant/Water in the Oil....but even that can become "skewed" for example, if you use a high-sodium motor oil, such as Mobil Super 5000....

And obviously, being able to see how far you can take any particular motor oil, provided you pay the extra price for TAN/TBN.....but it's got it's pros and cons.

Go with a "good" dino oil, change out every 3k?

Or go with a synthetic motor oil, sample at 8k, and see how much further you can take the particular oil and/or "fill" of brand X synthetic....?

 

[GROUCHO MARX]

Tells more about the engine than the motor oil.

Unless you've run that oil well past the manufacturer's recommendations.

 

[D189379]

I personally think the benefit is finding coolant, fuel, or other major issues with the motor.

I just find it odd reading through the UOA sections, that most comments are about low wear or high wear.

 

[ARB1977]

I've never done one. The only time will be if i have a water leak some were that i cant find.

 

[09_GXP]

I've had 3 UOAs performed over the past year.

The first one was because I am an engineer and like to over analyze stuff.

The second one was on my father's car which was loosing small amounts of coolant. The UOA showed coolant in the oil which pointed to a leaky intake manifold gasket which I replaced and confirmed it was bad.

The third one was for my Solstice which sees only aggressive, autocross, driving. The purpose of it was to see if my OCI was correct for the aggressive conditions. The UOA showed my OCI was pretty much spot on so I know I can continue that OCI.

 

[tig1]

For the average engine, UOAs are not much value, with the exception of unexplained coolant loss or perhaps to see if fuel delution is high due to injector problems, etc. I can do an OC for the cost of a UOA. As for determining actual engine wear, forget it.

 

[PandaBear]

Assuming the lab you use is calibrated and in good quality, you can use it to determine how long should you run your oil.

Most of the low cost labs like BStone have so many mistakes that I'd only use it to check if I have coolant leaks.

 

[Spector]

Unless you suspect a coolant loss ( probably already know due to low coolant in tank) or another issue they are not worth the cost. Wear numbers are not realiable unless you have years worth of trends to look at and even then, dependent on your driving, climate etc and rarely if ever result in premature engine failure. So really, coolant loss or another issue that is suspect but for routine how is the engine doing, a waste of money. Primarily because there is so little one can do to correct wear issues not caused by a component failure. Well, you could change your oil every 500 miles but that does not correct any wear issues, just makes for great UOA.

 

[Gene K]

Lets see in my case....

$3,000 extra in services (to many oil changes) or a $60,000 engine that lives a suboptimal live span because of overextended changes or not spotting a head gasket starting to leak. Also the possibility that some things may be caught early like a cam going bad (high iron readings) that allows for saving thousands in unscheduled down time.