Testing Oil by Smell/Appearance

[mrutkaus]

No flames, oil burns!

I think I can tell bad/worn out oil from good/usable oil in an engine by smelling oil from the dipstick, looking at it, and feeling it between my fingers.

No scientific tests to confirm this, just want to know if anybody else claims some accuracy doing this.

Mike

 

[20 20]

Anytime I buy a used vehicle one of the 1st things I do is check the oil. Smell, site, and feel have not let me down so far. I've not tried the taste test yet though

 

[mrutkaus]

LOL taste test. Might work, though.

Mike

 

[cedarbend]

yeah and you will be able to smell a wore out engine after while too.

 

[bp fick]

Sight and smell are essential in "sight seeing" a vehicle. Especially easy to spot is burnt brown and smelly ATF. There is a smell to that burnt stuff that's hard to forget. Stinky, sweet, leaking, evaporating off anti-freeze is pretty easy to remember too!

 

[Cami]

For "sight seeing" how about a little amateur paper chromatography? I put a drop of warm oil on a scrap of plain cardstock and let it sit and soak in; it can take a while. If the paper is right, then the oil will spread out and give some indication any contamination that might be present.

Even if you don't want to trust it, do it in front of the seller and see if he gets nervous.


No taste tests over her, but would you believe that my pinky finger is a crackerjack continuity tester?

 

[Opti-Mist]

Yes, with some experience, especially with known samples. If you know what fresh oil smells like you can certainly discern an oil that has been overheated. Likewise any grittyness would raise suspicions of the presence of foreign matter. As noted above, good things to do in front of a seller.

 

[mrutkaus]

Hey I've done that "amateur paper chromatography" also.

Mike

 

[Barry Bowen]

Testing by sight and smell may be the only thing available when you are looking at a piece to buy, but if you already own it and really want to know what is going on you need to have an actual analysis run. They are not that expensive, 15-20 bucks and on diesels you cannot beat all the info you will receive. These test have even shown me that I needed an air filter due to certain dirts in the oil. Once you have a track record of them on a given engine you will actually know what kind of shape the engine is maintaining. However, I due use all synthetics (Amsoil) so my drain intervals are much longer and I need to keep a better eye on things.

 

[Cami]

For sure, engine oil analysis is a great tool for learning the condition of an engine; you can spot problems before the become catastrophic failures. Also, oil analysis is great to help determine if you can get away with longer change intervals.

I had one fleet job where we did sampling through the local Finning dealership. The engines cost tens of thousands to replace, downtime was not acceptable, and the sumps held ~36 quarts of oil; for them sampling and extending change intervals, if possible, made sense.

Working for another fleet, no analysis was done but we had conservative change intervals; it all comes down to what the maintenance supervisor/customer wants.

I'm small potatoes: My own two trucks have Chevy small blocks. These engines are cheap, only hold six quarts of oil as they're set up, and since I do the maintenance the labour bill is zero; sampling would be excessive for me. As for the issue of downtime while repairs are made, machine availability isn't so critical for me and since my trucks are nothing special and I could easily rent a replacement on short notice.

Horses for courses....