oil - how dirty?

[prkaye]

How dirty should my oil be when I change it? Newly overhauled engine (new cylinders) using mineral oil. I did a change at 10 hours and again at 35 hours. Both times the old oil came out quite dark.

[Geico266]

Are you running 100LL?

Are you running the engine rich for break in?

Cute baby in the pic!

[prkaye]

yes 100LL. Ran it full rich for the first 10 hours or so. But after the first oil change was leaning during cruise, oil still came out dirty.
Thanks, Arya sure is a cutey (she's 2 this month). She was out at the airport with my wife on Sun and watched me takeoff. She apparently got really really excited, jumping up and down... "DADDY PLANE! IN THE SKY!! GOOOOO!"

[Russ McCutcheon]

It?s always going to look dark in the drain pan/jug. Look at the dip stick before you drain it, it will be tan to dark brown depending on the hours, never black like graphite/charcoal. If you?ve seen the oil drained from a diesel then you have seen black oil, if it?s dark brown then your fine, if it?s truly black then there could be a problem.

[rocketbob]

No worries. This is the dispersants in your oil at work. Diesel engines turn oil black within a few minutes of starting them after an oil change.

[DakotaHawk]

You've probably seen these testing kits available from various sources. I use Lab One testing kits. Lab One Testing Kit
A small jar, a mailing tube, and instructions are included in the purchase price of the kit. When you change your oil, simply fill the small jar with used oil, fill out the form indicating type of oil, hours of service, and type of engine. Three postage stamps on the mailing tube and drop the sample in the mail. Within a few days you'll have an analysis of the wear products in your oil via email and followed up with a hard copy letter.

The first sample will terrify you because it will say that everything is out of spec! But then the second sample done 50 hours later will have a baseline to work with and you'll have good info to work with.



This is how the report comes back from Lab One. Note that it has the first report highlighted in yellow and the new report in green because there is a good trend.

edit: When I place an order with Aircraft Spruce, I'll order enough oil filters to do a couple of oil changes, and purchase the same number of oil sample kits. The sample kits are pre-paid and never expire. Just draw the sample and drop the tube in the mail. No need to send any money.

[steve91t]

Originally Posted by rocketbob

No worries. This is the dispersants in your oil at work. Diesel engines turn oil black within a few minutes of starting them after an oil change.

Not mine! 7.3 Powerstroke just over 200,000 miles. Amazing engine.

I 2nd the oil analysis. I actually do this with my Powerstroke, just to see how it's doing. They give you a full report and keep track of the previous reports so you can see the trend.

It's very easy, cheap, and they are quick to respond. I use Blackstone.

Steve

[prkaye]

Thansk guys! I've just done an oil change and my old oil has been sitting out in an open plastic pan for a couple of weeks now, so it's probably too late to get that oil tested. But next oil change i'll send in a sample.

[allbee]

Originally Posted by prkaye

Thansk guys! I've just done an oil change and my old oil has been sitting out in an open plastic pan for a couple of weeks now, so it's probably too late to get that oil tested. But next oil change i'll send in a sample.

Why? I bet the oil sat in the engine a couple weeks as well. I would take a sample and send it in.

[prkaye]

I just assumed that being exposed to open air, dust etc would contaminate it, but if that's no problem, I can pull a sample from the pan.
Although, the oil i just drained is mineral oil and i just switched to Aeroshell 15W50. Perhaps it's better to do my first analysis with the Aeroshell that i will be using regularly, to provide a more consistent baseline for comparison?