Synthetic Engine Oil - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

Synthetic Engine Oil by dieselsmoke on 29 Apr, 2009 10:47
Is there a certain type and weight of synthetic engine oil that should be used for the 1.9 AAZ engines???
#1 by arb on 29 Apr, 2009 10:57
I'm partial to Mobil-1 in my diesels.

http://www.mobiloil.com/usa-english/motoroil/car_care/which_oil/WhichOilManualResults.aspx?option=1

this tool says you should use Mobil-1 SuperSyn 0w-40. The German automakers approve of it:
http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_0W-40.aspx

I like a little thicker - 15w-50
http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_15W-50_.aspx
#2 by arb on 29 Apr, 2009 11:26
Quote from: "libbybapa"
I typically use 10w-40 Mobil 1. DO NOT use synth oil during engine break-in.

I jumped the gun once. I punched the block myself to .030" over to true the bores. I used Quaker State dyno oil for the first 10,000 miles. Thought it was broken in. HA !! I then burned through maybe 5 gallons of oil over the next 20,000 miles until those rings really seated.

Now, I wait 30,000 miles for a rebuild. New cars are different. Many OEM's ship their engines with full synthetic because they get higher EPA mpg numbers to advertise. Their manufacturing processes have also improved to the point most engines are already "broken in" from the factory. The Ford Windsor Engines are a good example. After the block is honed to a mirror finish, each bore is precision measured for bore. Then, the computer matches the best fit piston from 8 different sizes - all 8 sizes are steps within the bore tolerance - maybe its 0.001" and each step is about 0.000125" apart. Each piston is similarly measured and indexed by size within spec. A robot does the indexing and sorting to hand the human the right piston for each bore. This results in a broken in engine that is sealed very good from the word go.
#3 by Vincent Waldon on 29 Apr, 2009 11:37
Any synthetic with a CG-4 or better is all good.. VW has a 505 standard they speced back in 1993+ but it is not something current oil manufacturers will ever reference in 2009.

Common synthetic oils that meet this spec include:
Note that the much-more-commonly-available Castrol Syntec is diesel rated but only has a CF level... technically good enough for 1.6s but not technically correct for AAZ and definately not enough for TDI engines by most folk's reckoning. There's also conflicting evidence as to whether it's a true synthetic in the way all other manufactures use the word.

I can't imagine why an oil that works in a 1.6 won't be fine in a 1.9... and it's probably just the fact that the ratings have changed over the years, but having just learned of this nuance I'll not be buying any more Castrol Syntec for my fleet... ok, maybe just for my gasser!
#4 by arb on 29 Apr, 2009 11:59
Quote from: "Vincent Waldon"
Common synthetic oils that meet this spec include:
Add to this list Mobil Delvac 1 full synthetic for diesels with oil change intervals of 60,000 miles or more !
http://www.superiorpetroleum.com/html/delvac_1.html
#5 by colectb on 29 Apr, 2009 14:50
Uh... My rebuilt audi 5k td is still in its break-in period, I probably have 10k miles on it.... and I put in Synthetic.... Is this bad, what did I mess up??? I noticed It is burning more oil and leaking from the oil cooler or turbo just recently (before there was only a drop from the turbo every once in awhile) , but can I get some more info please?? I hope I didn't mess anything up!!! The rings are the Total Seal gapless rings if that helps too.

Thanks
#6 by Dakotakid on 29 Apr, 2009 16:20
Watch them words, Pilgrim.
This 'ere is a family oriented forum. Plus, we gots a few feminists readin' this, too.

Yew don't want to gives them folks da idea-err that we's ain't purty well dun be edu-kat-ed up 'ere in the Dakotas!!!!!!!!! :roll:

Seriously, there is such a thing as draining it out now.
#7 by burn_your_money on 29 Apr, 2009 16:25
Sorry Dakotakid, I edited his post already
#8 by colectb on 29 Apr, 2009 16:25
Well I'm wondering what the effects are if I run it in the car? Does it just seep past the rings and burn off before they are seated, or can it cause actual damage? I just want a better explanation.

The above post kind of had me scared, but I won't put dino oil in until next oil change if I don't absolutely have to.

Oh, and sorry for the choice of words, I didn't catch it.. :shock:
#9 by Vincent Waldon on 29 Apr, 2009 16:46
Quote from: "colectb"
I just want a better explanation.

No problem.

The basic idea is that during the first 10K miles or more you car is trying to break in...the rings are seating, bearings are shedding any micro-impurities they trap, and while this is happening a little bit of friction is a good thing.

This is especially important for the rings.. they really need to do a bit of rubbing so that they seat properly against the walls of the cylinder. If they don't do this the cylinder walls develop a glaze and the rings never seat.

So... a little friction is good during break-in. The trouble with synthetic oils is that they are *too* good at what they do.. too slippery... and so they extend the break-in period or, worst case, prevent the rings from seating properly, period.

Best practice therefore seems to be to run conventional oil for the first 10K miles or so, until oil consumption has stabilized, any initial blue smoke is gone, and you're convinced that the rings have seated themselves. Some folks track compression as a way to measure this.. I mostly use oil consumption.

If you can stomach it, it'd be a good idea to get that slippery oil outta there as soon as practical and run some dino instead so that friction has a chance to do it's work.
#10 by arb on 29 Apr, 2009 18:23
You just switched at 10K and now see consumption and leaks ? You have 2 choices, assume you are broke-in but you chose think synthetic - you did NOT use a "Blend" - right ? It is snake oil. By law, they can call it a blend with less than 1% synthetic... So, maybe you have 0w-30 in it... you could switch to 15w-50 and see if it stops (means you were broke-in), or switch back to dyno for another 5K or 10K.... the seals have nothing to do with brake-in. Your journals might not be full height (it was turned ?) or grooved. Thick oil should solve this....

If you just switched, you didn't harm anything if it has not been broke-in yet...
#11 by clbanman on 30 Apr, 2009 09:38
Just for a bit of reference on how much difference the oil can make, a friend used to race go-karts. Honda 5 hp engines. Using dino oil, 2-3 rebuilds per racing season in Ontario. Switched to Mobil 1 synthetic, and ran a rebuilt engine for the entire season without taking it apart once. Tore it down after the racing season ended, and he said you could still clearly see the crosshatch pattern on the cylinder walls from the honing. He said with dino, the cylinder walls would have been like a mirror each time he did a rebuild.
#12 by colectb on 30 Apr, 2009 11:38
Ok, thank everyone for the explanations. I am running full synthetic Rotella 5w40. I never had a drop of consumption before, and now its almost a quart every 1000 miles. So yeah, I guess I'll throw some dino oil back in. Thanks guys!
#13 by jtanguay on 30 Apr, 2009 13:42
Quote from: "colectb"
Ok, thank everyone for the explanations. I am running full synthetic Rotella 5w40. I never had a drop of consumption before, and now its almost a quart every 1000 miles. So yeah, I guess I'll throw some dino oil back in. Thanks guys!

do that, and then you need to drive the car fairly hard. high rpm's, and 5th gear pulls from 50 km/h to 100km/h. only do this when the car is up to temperature though!!!