L322 Paper test for Diesel in engine oil

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youmitegetian

youmitegetian

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So after having the injectors replaced it was suggested that my "tappy" tip end could be due to diesel getting into the engine oil causing it to run to thin.
I read up on a paper test to see if this is the case.
From what I can gather my results suggest the oil is ok but what do you guys think? The oil was changed around 1000 miles and 2-3 months ago
IMG_7597.JPG
 
Ah do you think that's diesel. I looked at test samples that suggested if it's got diesel in the oil it will have a transparent ring around the centre rather than black/grey
 
Tbh I'd never heard of this 'test' before so my comment is based on 2 minutes reading a few posts in a diesel forum.
You'll no doubt have read about soot load, paper type and oil temp.

I'd have guessed the ring would be definitive if diesel was present, just not convinced it would be totally clear but I'm certainly no expert.
Any experiment needs a control so any pics of clean sample would be a help as I haven't seen one.
 
Why not make a small sample of engine oil with a drop of diesel in it and replicate. Unfotunately I took my waste engine oil down the tip last week or I would do it out of interest.

Cheers
 
I've never heard of this paper test either but I would have thought you would be able to smell diesel in oil. A little diesel in the oil won't hurt anyway. Try adding a thicker grade if you are worried about it thinning out.

Col
 
Well I found some old engine oil and a little bit of diesel.

As expected, UEO is black on the paper.
approx 5% diesel leaves a very slight grey ring on the outside of a black ctr.
approx 25% diesel leaves slightly more of a light grey ring on the outside of a black ctr.

If I get chance later I will go do it again and take photos.

But from a very small sample of what was left in the waste oil container and the dregs in the bottom of the diesel container.

Cheers
 
Last edited:
I was thinking I'd do a sample test as suggested. I have some oil from a diesel Volvo that I can use. The oil doesn't raise but doesn't drop either and at 230000 miles I'd expect it to use some oil. It was only suggested that I might have diesel in the oil due to the engine being tappy and it needing replacement injectors due to misfire and smoke on cold start. I'd never heard of this test until an old school mechanic suggested it to me and then I did some reading up. Apparently the oil has to be warm for this to work
 
It was in case you had regen problems, but non dpf model should be a reasonable control test if it is running well.
Best surefire test is lab test of course, but think they are c. £60.
 
So I did a test sample tonight with used oil and oil with diesel mixed, samples were cold but the one with diesel had an obvious transparent ring around the outside whereas the other didn't. It was in the car a lot longer than my oil and gave a solid colour unlike mine but both samples were done with cold oil so may have been different if heated.
I would of taken photos but phone went flat. Will add them later if I think about it.
 
Last edited:
youmitegetian said:
So I did a test sample tonight if used oil and oil with fiesel mixed, samples were cold but the one with diesel had an obvious transparent ring around the outside whereas the other didn't. It was in the car a lot longer than my oil and gave a solid colour unlike mine but both samples were done with cold oil so may have been different if heated.
I would of taken photos but phone went flat. Will add them later if I think about it.
Click to expand...

Same as I found in post 9 then, only thing I found was after leaving it for a while the witness became harder to read. I think best results are visible after approx 1 minute. How much did you mix them ratio wise?

Cheers
 
Edited
I didn't measure to be honest just added a little to see, I didn't disbelieve your test just curious I guess.
I wonder why mine has the dark ring through it, does appear to be ok though,
Might steal the wife's BMW and test that oil just as another comparison
 
Well more of a darker centre really. If it's got nothing but oil surely the discoloured paper should be a solid colour and not lighter on the outside
 
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