Hi Folks

Could anyone help me with this first analysis at 55400KM - 3800km on the oil including a few track days.

Reason I ask is that I had a lot of gritty friable carbon deposits in the oil filter and I am having reduced oil pressure levels at idle when hot and hotter oil temps on track, up to 248F lately (at 50F ambient). The oil temps at successive track days have been getting hotter and hotter for some reason.

I'm wondering if the oil cooler is partially blocked with carbon deposits, giving the hotter temps and the carbon deposits in the filter (which I didn't see at the last oil change). I might put a flush through next time? Servicing looks like it's been done properly in the past, But I suspect only at the factory intervals which are way way too high. Oil is Castrol Edge with Titanium 0W-40. The report didn't flag anything as a problem.

Manual car without 3rd rad and normal thermostat.
oil analysis.jpg

 

Can't comment on your OA results, but I had similar symptoms which persisted until I sorted out the fuel system. Fuel dilution (which doesn't always show up on an OA report) causes varnish which plates out on the inside of the oil cooler, causing high temps.

I have always run Mobil 1 5W50 and my hot idle oil pressure went from 2-2.5 bar to a rock solid 3.5 bar once I sorted out the fuel system. Also, my noisy hydraulic tappets shut up as well - another indicator that varnish was forming but has now been removed.

Now I'm running the new Mobil 1 10W60 "extended life" brew, and my hot idle oil pressure has progressively (!) risen to 4.3-4.5 bar.

Changing the oil filter more often helps prevent varnish buildup - the varnish is adsorbed onto the cellulose.

Have a read here: http://www.cjc.dk/fileadmin/user_upl...on_Varnish.pdf

Hope this helps!

Cheers,
Mike

 

what was wrong with your fuel system? Did you do any flushes? How did you remove the varnish?

 

FPR had failed high, and the injectors were unbalanced (flow) meaning that some cyls were running slightly lean and others slightly rich = fuel dilution of the oil. I replaced the FPR and used some Techron injector cleaner.
Caltex Techron fuel injector cleaner is great stuff - as recommended by Porsche. (theres a Porsche technical service bulletin about using it). $23/bottle at my local Caltex station.

No flushes required, just change oil and filter more often. Clean oil will dissolve varnish, and a clean filter will adsorb the varnish from the oil before it can plate out again. This assumes that the CAUSE of the varnish has been addressed!

Flushes can be a bit aggressive and loosen a lot of crap that can cause damage before it can be filtered out. I prefer to let the oil do the work.

Cheers,
Mike

 

HI Kiwi,
I can’t see anything alarming in your UOA.
Slightly elevated Fe = 15
and (not sure what it says) = 20 - can you clarify

The problems I can see are as follows:
Carbon deposits in oil filter – possibly causing reduced oil pressure. Would you quantify reduced oil prssures.
For example my 2005 C2S with 60,000 kms will peg at 5 bar at about 2700 RPMs fully warmed up to 200*F (~95*C) and I get 2 bars of pressure at idle speed.

High oil temperature in relatively low ambient (50*F = 10*C). Oil exchanges heat with coolant in a heat exchanger mounted over cylinder bank #2 (cyl. 4, 5 and 6). You indicate increasing oil temperatures with track days. That would indicate a problem with cooling system. The usual suspects: Water pump, T-Stat, dirty or leaking radiators, leaks in cooling system in general that cause possible overheating. This overheating is not significant yet to register as increased coolant temperature mostly because the gauge is not accurate enough. Data logging with Durametric would shed more light.
In other words cool ambients (10*C) don't cool enough your coolant which subsequently does not cool enough your oil causing increased oil temps.

It is hard to diagnose complex machinery over the internet.
My suggestion would be to take care of cooling system first. A 160*F T-stat, 3-rd rad, new water pump, fresh coolant with water wetter as a good start.

Then look at your carbon deposits in oil. Fill engine with high detergent oil and fresh filter.
An ACEA A3/B4 oil with high Ca and Mg that is full SAPS ( a more conservative oil with proven UOA’s from M97 engine) and run it for a short period (2-3 T km). Then drain it, inspect filter and see how your deposits are trending.
It would definitely help to have a good mechanic oversee the above.

Edit:
The following note added:

At 250*F your Castrol Edge 0W-40 Titanium is at about 8.8 cSt = XW-20 grade lubricant @ 100*C.

Cheers,
=L=

 

I think your increased oil temp is normal for track driving. I have an 06 manual and I can get up to 225 sitting in traffic. On the track on a warm day I've gotten up to about 250 but then during the cooling lap the temps dropped back down. You could install the third radiator kit if you're concerned but I don't think that oil temp is to be unexpected.

 

HI Kiwi,
I can’t see anything alarming in your UOA.
Slightly elevated Fe = 15
and (not sure what it says) = 20 - can you clarify Yes it is Cu

The problems I can see are as follows:
Carbon deposits in oil filter – possibly causing reduced oil pressure. Would you quantify reduced oil prssures. Well I used to get 2-3 bar at hot idle, now more like 1-2 Bar. Car doesn't use any oil.
For example my 2005 C2S with 60,000 kms will peg at 5 bar at about 2700 RPMs fully warmed up to 200*F (~95*C) and I get 2 bars of pressure at idle speed. I get full pressure at 3-4Krpm.

High oil temperature in relatively low ambient (50*F = 10*C). Oil exchanges heat with coolant in a heat exchanger mounted over cylinder bank #2 (cyl. 4, 5 and 6). You indicate increasing oil temperatures with track days. That would indicate a problem with cooling system. The usual suspects: Water pump, T-Stat, dirty or leaking radiators, leaks in cooling system in general that cause possible overheating. This overheating is not significant yet to register as increased coolant temperature mostly because the gauge is not accurate enough. Data logging with Durametric would shed more light.
In other words cool ambients (10*C) don't cool enough your coolant which subsequently does not cool enough your oil causing increased oil temps. Radiators are all in very good condition - no corrosion and no debris in them. Water pump? Maybe I wouldn't know. I don't have a durametric unfortunately!

It is hard to diagnose complex machinery over the internet.
My suggestion would be to take care of cooling system first. A 160*F T-stat, 3-rd rad, new water pump, fresh coolant with water wetter as a good start.

Then look at your carbon deposits in oil. Fill engine with high detergent oil and fresh filter. I have always done this, but maybe my harder driving is removing the varnish from previous owners lazy driving?
An ACEA A3/B4 oil with high Ca and Mg that is full SAPS ( a more conservative oil with proven UOA’s from M97 engine) and run it for a short period (2-3 T km). Then drain it, inspect filter and see how your deposits are trending.
It would definitely help to have a good mechanic oversee the above.

Edit:
The following note added:

At 250*F your Castrol Edge 0W-40 Titanium is at about 8.8 cSt = XW-20 grade lubricant @ 100*C. Not sure where you get this from - the viscosity of 68.6 is at 40DegC.

Cheers,

 

I retrieved Castrol 0W-40 T data sheet from the internet and plotted KV 40 & 100 here:

http://www.widman.biz/English/Calculators/Graph.html

And adjusted temperature range to show 250*F = 120*C. (approx.)
Which gave me KV (120*C) = 8.8 cSt.
What concerns me is that at very low ambient (10*C) your engine oil temp. sits in relatively hot range.
If that were my car, I would modify my cooling system (which I did on my car, even though I don't track my car) as per my previous post and consider oil that would stay within 40 grade viscosity at my operating temparature.

The link above will help you to determine what viscosity that would be, but most likely you are into XW-50 range if your temps. on track remain elevated.
Hope it all makes sense.
I personally use Millers CFS 5W-40 NT for fast road use which reduced and stabilised my oil temps. even further to the point that on a hot day (29*C, please don't laugh, that's all we get here!) my oil temp. after a hard run up a long hill would not exceed (ever) ~210*F and quickly drop back to 200F even when car is standing still at traffic lights. I would S**T my pants if I saw 225F and likely die to a heart attack upon 250F.
Again, cooling and lubrication are two most critical aspects of reliability in M96/97 engines and closely tied with each other. These engines are NOT Mezger engines, keep that in mind.
That's my personal experience. I also sell Millers products where I live so please take that into account.
Let me know if I can help with anything else.
Cheers,
=L=

 

The car still runs around 90-100 degC oil when on normal road driving, just when on the track lately are the oil temps getting a bit higher. Why would this be happening? Where are the carbonocaceous (?) compounds in the filter coming from?

This oil is all I have used in the car and first few track days I would only see 110-115 max. I will however be going to Mobil 1 5w-50 next.
Temps drop off fairly fast when I slow down for cool down lap.