vacuum leak -

[ahoier]

I had a thought the other day regarding Used oil analysis....I know some say they are garbage, others are all about them, etc...and well, I'm kind of curious; I see the "potential" they have. Something I've been thinking, if a vehicle has a "vacuum leak" - basically, the engine getting air into the engine that would not be filtered by the "air filter" - would that show up on a used oil analysis when taking the sample through the dip stick and/or as the oil is draining.

Obviously, taking the sample from the oil within the filter wouldn't quite work....cause there should be possible contaminants within the oil filter; since that's it's job.

I know I've read some UOAs where B-S noted "particulates" - likely due to clogged/dirty or perhaps even "NO" air filter present....which is why I had this thought.

Obviously the role of the oil is to suspend the "contaminants" that could make it through the vacuum leak.

Obviously though, if the "leak" is big enough the vehicle would not start....or will drive like "stuff" lol.

 

[Kestas]

Yes, particulate contaminant may get ingested by a vacuum leak, but the volume of air would be a miniscule percentage of the total volume of air going into the engine. It would have to be very dirty air for this to happen. If you look at an air filter after 30K, you'd see all the contaminants that were stopped in that time. Think of the small percentage of these contaminants and you'll appreciate the small amount of contaminants that could ever fine their way into the oil between oil changes.

And any particles that do end up in the oil (most go through the exhaust) will eventually be filtered out by the oil filter.

Given the tiny probabilities, I don't think any small vacuum leak would show up in a UOA.

 

[Volvo_ST1]

aholer, I believe a vacuum leak would result in higher than normal Si levels due to Si particle ingestion.