Mazda 3 1.6 DV6C UOA Low TBN Qeustion

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Jul 10, 2019
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Location
Ireland
Hi all

The engine is 1.6 turbo diesel which make about 109 to 112 hp depending who your talking to.

Just got my UOA back, The oil was in the engine for 5000km(3000miles).
The recommend OCI is about 20,000km/12 month but like most people here I question that using UOA like this.
The car is new to me after 235,000km(150000miles), sound good and drives well. The previous owner OCI was 18-25,000km(11.25-15,625miles)
Thinking of running a "flush oil" with or with a oil cleaning additive as these early version (DV6A and DV6) of these engine are known for blowing turbo via a clogged mesh filter on the turbo oil feed pipe. Any advice regarding this would be greatly appreciated.

The main question is how is the TBN so low after this distance. also point out anything else that's wrong with it but I don't think its that bad.

[Linked Image]
 
That's a huge drop. Isn't the TBN of virgin Castrol 5w-30 around 11?
What I don't see on your report is TAN number which has an influence on TBN.
As TAN increases the TBN goes down.
 
I think the previous owner did too long oil change intervals. Maybe forgot an oil change or two.
Sludged turbo engines and bio-diesel (EU diesel) can kill TBN quick. Also high sulfur diesel(East European suppliers do produce such, for farm use and such) can do the same.
Using an oil flush is riskier than running a few short 3-5k km OCI's.
Do another check after that, to confirm things are coming back to normal with normal use - fuel and OCI.
 
Hi all,

Yea sorry forgot to say I don't know if it was castrol edge. But I did know it a 5w-30 just don't know what one. previous owner forgot the brand.
well long changes yea, but forget I don't think so was washed every week and wax once a month and the paint shows it.

our diesel is 7% bio diesel here. don't know if that anuf first diesel car still learning.

but would the OCI show any built up carbon or is the only way taking the valve cover off and having a look?
 
7% is the maximum, there can be as little as no bio diesel in the fuel. Infineum has a download page where they tested european diesel including for FAME content. The link to their page was posted elsewhere on the forum, I will look for it and link here.

You won't find any carbon buildup under the valve cover, the places to find it are the turbo feed pipe and the oil pick up mesh.

What is the oil capacity in reality for your engine? the PSA engines got a shorter dispstick as a modification, which increased oil capacity to 4.2 litres but the official capacity remained 3.75l. This was done to reduce the carbon content. Also the air filter change interval was reduced.

The oil analysis can show soot content, but yours seems low-ish at 0.7%. Does the oil smell sooty or do you feel any grit?

Don't forget c3 oils can have a starting TBN as low as 6.0 if it's an older stash so you have over 25% remaining in that case. I also wonder what the repeatability of the test is.

We used to run these engines with full saps oils up to 2008 at least, the dpfs didnt mind back then...

In any event, change the oil now so you know what you are running at least.
 
Thanks for the response Jetronic.
Read thought that there. It a nice read for anyone look to see how you diesel stack up to the worlds.

I will change the Oil as soon as i get a chance. I will see if I get to have a look at in the sump and inspect it.

If it is clean il just run a short oil change and get back to around 7-8km OCI and test again.
If it is someone dirty then il run the flush then drop that oil and repept if clean.
If it is very dirty then il run short OCI for two or three 3-5km and then repeat if somewhat dirty.

If anyone can poke some holes in that logic please do so.

The oil I will use untill the 7-8km OCI will be is Castorl Magnetic C3 cause I have a lot of it. Then il swap to Mobli 1 ESP as that has the best spec If you think I should use somthing else please post here[1]

Thanks again for the responses.

[1]https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5446959/2
 
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If you are going to run very short OCI, any cheap oil will do that has a diesel certification. The castrol magnatec should be good enough so you can use it when it's time to go longer oci again. For now oil from lidl or aldi will do (15w-40 or 10w-40).

Checking the oil pickup mesh in the sump is definitely the way to go on a new to you vehicle with a DV6. Get a new pickup tube one if you can't get it spotless. Removing the oil feed to the turbo for inspection should be easy aswell.
 
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The oil might have been longer in there than 5000 km . The low TBN and 0.7soot point to that . 0.7weight % soot seems high for 5000km in a common rail engine.I'd expect this number for a mechanically governed diesel at that interval)...if the lab is right of course.

I would not use flush at all.

Change oil and sample again at the same interval (with TBN and TAN)

There is nothing in this engine that mandates (viscosity-wise) the use of energy-conserving HT/HS 10 mgKOH/g...SA around 1wt.%)


Rimula R6 LME 5w-30

https://www.mobil.com/en-AT/Commercial-Vehicle-Lube/pds/EU-XX-Mobil-Delvac-1-LE-5W30
...TBN 13mgKOH/g(!)...they've either reformulated it again or it is a typo...

What was the oil consumption for these 5000km.? What are the exact names of the Castrol and Mobil C3 oils that you plan to use?
 
sorry for the late response all.

Yea I get yea I'll see if I can get a cheaper oil just for now. i don't think its a picky engine either.

Bought a new oil pick up since its plastic I didn't want to clean as I thought the a cleaner could have made it weaker. and it was only 20 euro thank god its not a Mazda engine as part for Mazda's own engine are a lot more expensive but are probably metal.
Yea it might have been in longer then 5000km, have the sump off and will upload picture later to show how fecking clean it was, I was shocked.

I am a bit weary of using a heavy diesel motor oil as they have to have different makeup to withstand different operating conditions.

I will run this engine oil for the

There was no oil consumption that i could read, i.e. no movement on the dip stick. the names are. Castrol magntic c3 5w-30[1], and mobil 1 esp 5w-30 [2] I was looking at buying the mobil 1 here [3]

[1] https://www.castrol.com/en_gb/unite...ol-magnatec-stop-start.html#tab_5w-30-c3
[2] https://www.mobil.co.uk/en-gb/product/mobil-1-esp-5w-30/
[3] https://www.autodoc.co.uk/mobil/9022445
 
Originally Posted by Jetronic

The oil analysis can show soot content, but yours seems low-ish at 0.7%. Does the oil smell sooty or do you feel any grit?


The sumps oil did feel a small bit grity but using the the dip stick it felt fine. The sump is all cleaned out now.
 
Originally Posted by Jetronic

What is the oil capacity in reality for your engine? the PSA engines got a shorter dispstick as a modification, which increased oil capacity to 4.2 litres but the official capacity remained 3.75l. This was done to reduce the carbon content. Also the air filter change interval was reduced.


yep your right here a source for proof[1] with a different car but same engine.

[1] http://mmc-manuals.ru/manuals/asx/online/Service_Manual/2019/12/html/M112100040370000ENG.HTM
 
Originally Posted by Jetronic
Checking the oil pickup mesh in the sump is definitely the way to go on a new to you vehicle with a DV6. Get a new pickup tube one if you can't get it spotless. Removing the oil feed to the turbo for inspection should be easy aswell.

Thank you for the heads up I forgot to clean that I will clean that before I got today.
 
Originally Posted by mossietheno1
Originally Posted by Jetronic
The psa versions used to have a metal pick up for the oil.


not sure if that true as i bought the Peugeot/Citroen part (psa).
here a link to a workshop manual [1] (section 3.1) that states all dv line (not including the dv8) have plastic pickup strainer.

[1] http://mmc-manuals.ru/manuals/asx/online/Service_Manual/2018/11/ENG/1CMJ/B1BB015UP0.html


Could be, it's been over 10 years since I changed them. I would have thought I'd remember them being plastic, but apparently not.
 
Originally Posted by mossietheno1
Originally Posted by Jetronic

What is the oil capacity in reality for your engine? the PSA engines got a shorter dispstick as a modification, which increased oil capacity to 4.2 litres but the official capacity remained 3.75l. This was done to reduce the carbon content. Also the air filter change interval was reduced.


yep your right here a source for proof[1] with a different car but same engine.

[1] http://mmc-manuals.ru/manuals/asx/online/Service_Manual/2019/12/html/M112100040370000ENG.HTM


that link is for the wrong engine, but i put in 5 litres of engine oil in my car after taking off my sump and it is 3/4 full now. There was a less then half a liter wasted from taking off the sump. so its not 3.7 anyways.
 
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[Linked Image]

[Linked Image]

This picture has the new oil strainer on.
[Linked Image]


Here is the pictures of the engine, the sump had no chucks in it or anything i just poured what was left in it through a tissue and there was nothing.
Do you think there was a something else the previous owner did, like a flush at the end of the OCI?

Thanks again for everyone help.
 
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all I can think of is you have a bigger sump...

Did an oil change on a recent mitsubishi ASX with a 1.6 dv engine last week and it took 3.9 litres.
 
Originally Posted by Jetronic
all I can think of is you have a bigger sump...

Did an oil change on a recent mitsubishi ASX with a 1.6 dv engine last week and it took 3.9 litres.


Was that older then 2010?
I'm thinking the same as yourself with the dipstick, the last car i drove a Toyota avensis 3zz-fe got its dipstick changed to stop a the piston rings getting stuck.
I think your right 3.9 or 4L and another 1/3 liter to half a liter because the sump was taken off and not drained The sump plug is also flush with sump bottom which I don't like, keep a lot of oil in the sump.
 
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