# 06 Jetta 2.0T



## guy688i (Sep 3, 2007)

Disclaimer: I am clueless when it comes to car/mechanical issues.

I went to check my oil while filling up with gas this afternoon, and noticed that the oil was barely on the min line on the dipstick. I carry a quart of Mobil 1 0W-40 with me to be safe. I opened the oil cap and noticed the "mud" like substance on the top, however the dipstick came out clean. After doing some research on here, it seems to be the sign of a blown head gasket or condensation. I also noticed the coolant level was below were it normally was, but well above the min range. I live in WY and the temperatures have varied from -9 to in the mid 50s in the last 2 weeks. I also drive short distances at a time.

Before adding the oil, I opened the coolant reservoir and heard a popping sound from breaking the vacuum that had formed inside. I then reattached the lid. I drove the car hard to increase the temp to burn off the "mud" from the condensation as suggested by several posters. When I got back from the 30 min drive, the mud was gone (I wiped off the mud on the cap before driving, but not the mud inside the fill area) and the coolant level was much higher than earlier.

Any ideas on what happened here? Was it as simple as condensation on the cap from temp swings? Did releasing pressure from the coolant reservoir do anything? Is it safe to rule out a blown head gasket?

Thanks.


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## saaber2 (Jul 15, 2008)

All is likely normal. Condensation on cap. Coolant level change due to temp/pressure change. The simplest way to check for a headgasket is to look at the dipstick when the engine is warm. If the oil is milky then you have coolant intrusion. Have to check warm due to oil and water separating when cold/no mixing.

Also I personally wouldn't use M1 0w40 in this engine. It thins very rapidly. Viscosity loss rates are 18-25% on the 2.0FSI in around 3k-5k miles. Typical manufacturer condemnation limits are 10% viscosity loss (Kv100). We have 24 M1 0w40 used oil analyses for the 2.0 FSI and 23 of those thinned out of grade. The only one in grade had a kv100 of 12.53 and the limit for a 40 weight oil is 12.5 so it made it by only 0.03 Also Terry Dyson the oil expert form Dyson Analysis has been quoted as saying wear control using M1 0w40 on the BMW direct injection engines is only good enough for about 1000 miles or so. I understand this is due to the fuel dilution these direct injection engines dish out. I'm not saying M1 0W40 is a bad oil. All the data we have and Dyson say this oil is a poor fit for DI engines. Also it seems that nearly all the PAO-based VW 502 oils all perform similarly poorly (again based on UOAs and Dyson analysis). This makes sense because they are all built down to the same specification. These oils are tested in Europe where the cars run in lean burn mode which produces less fuel dilution than our cars here in the U.S.

Also FYI I was using it recently on a short run just to test my car after returning pcv system back to stock and it lays down deposits on the valves extremely quickly. We are talking about deposits in tens of miles not 100's or 1000's. Intake valve deposits are the silent killer on direct injection engines. This vortex poster used M1 0w40 changed every 10k according to the manual and here is what his valves looked like:










I would recommend a stout, ester-based 5w40. Shear rates can be as low as 10-15% with those oils in around 5k miles, depending on what oil you are using. These oils are the only ones that can take the punishment of these engines IMO. Also you may see your condensation issue go away using an ester-based oil. Personally I have never seen the condensation under the cap in 42k miles on my car which has lived on ester-based oils. But that could be due to individual engine differences or because I had my pcv bypass in for a long time so it may not be due to the oil. You'd have to switch and see if the condensation issue goes away to find out for sure.


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## gmikel (Nov 10, 2010)

:thumbup::thumbup:


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## guy688i (Sep 3, 2007)

saaber2 said:


> ...I would recommend a stout, ester-based 5w40...


Thanks for all the info! I think I understood 80% of what you said. When you say stout, ester-based; does this mean full synth or something different? Can you recommend a brand?

Again, thanks for all the help.


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## gmikel (Nov 10, 2010)

*earl*

i can't argue with saber2 but personally have had luck with 502 oils. most of my driving is between 10 and 50 miles per trip though. i don't idle my engine very much and change the oil between 4-5k. until about 3500 miles i have 0 oil consumption, after that i use about 1/2 quart until the oil change, so something definately happens to the oil. gml


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