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Yellow Mayonnaise gunk in oil filler cap

Jos-hawks Apr 6, 2017

  1. Jos-hawks

    Jos-hawks Registered User

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    :sign imnew:Hi, new to the forum so sorry if this is in the wrong place or something, but I recently had the yellow engine oil light come on. Check the oil level and it's absolutely fine and took my filler cap off to find lots of yellowish mayonnaise like gunk? I'm guessing the light is just the oil level sensor but anyone had this mayonnaise like stuff appear before?

    Thinking it could either be a blow head gasket or just condensation as I drive 3 miles every morning at 6am in the cold. Any help would be appreciated
     
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  3. Mario

    Mario Registered User

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    How bad is it? I have seen a little very thin / light coating on other engines due to condensation, but not on the Audi. Does it smoke on startup? May be worth draining your oil and see how it comes out. If it looks the same then it's water mixing with the oil via the head gasket or a cracked block (less likely). If it looks fine and you catch it in a clean container you can re-use it back in the engine, so won't cost you anything.

    If it looks ok I would still do a sniff test & compression test to confirm the head gasket is good. Both are cheap and easy. You can buy the kit for £70 to do both tests from Amazon or pay the garage 1 hours labour to check for you. If draining the oil and checking it, the sniff test and compression all come back good then nothing to worry about.

    As for the oil light, might just be a faulty sensor / bad connection??
     
  4. Rayner_1704

    Rayner_1704 DAN

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    Have you checked your water ? Sounds like head gasket to me
     
  5. LEE69

    LEE69 07 170 DSG

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    Yellow is oil level
     
  6. ab1702

    ab1702 Registered User

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    id probably clean the filler cap and around the top of the hole and then take it for a decent drive to get it up to temperature for a while and then when you get back leave it until the next day and then check it again. Sounds like condensation to me as if you're doing regular 3 mile journeys then the car and oil will not be up to temperature by the time you get there.
     
  7. Marek196c

    Marek196c Gilera Runner / A3 Sportback

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    I'm doing actually like 8months 1mile drive and nothing wrong, but mayo under your cap is definitely water mixed with oil, can be other the causes mentioned on top, also (depend of car) radiator (some of them are divided in 2 parts 1 for oil and other for liquid) or dpf (unlikely but worth to check it).
     
  8. Dannymoto

    Dannymoto Registered User

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    Potentially caused by a condensation build up if you're doing short journeys, take it for a long drive and see if it returns.
     
  9. Jos-hawks

    Jos-hawks Registered User

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    I've cleaned off all the mayo gunk and I'll take it for a long run tonight on my way to work to see if this helps.
     
    Dannymoto likes this.
  10. Essflee

    Essflee Registered User

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    As a couple of the other lads have said, sounds like condensation because of the short journeys.

    The old A3/S3 8L's do the same.
     
  11. Whodafunk

    Whodafunk Registered User

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    Check your dipstick. If there's gunk on that then it's water mixing with oil as condensation can't collect there.

    More thank likely with the winter and short journeys it's probably condensation though. Give it a good long run and hopefully it will clear as others have said
     
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  13. nluk100

    nluk100 Registered User

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    I'd replace your oil at a specialist and ask them to check for potential water in the oil. As above, it is probably just condensation build up.
     
  14. Stakeknife

    Stakeknife Registered User

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    Had this on every tfsi engine I've owned. As said, It's most likely just condensation with the colder weather and low miles, don't think the location of the oil cap helps.
    Now it's getting warmer the exhaust condensation will stop and the mayo build up. Peace of mind for 6months ha.
     
  15. SootySport

    SootySport Registered User

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    Hopefully just condensation due to short journeys. For peace of mind buy a HG test kit.
     
  16. Nessy

    Nessy VW + Audi mad

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    Any regular use of a vehicle where an engine doesn't get up to normal operating temperature for each journey is never going to be much good for any car tbh, if it has to be done I'd say make sure the drive is long enough every now and then to get the engine nice and hot.
    On air-cooled VW engines (which are as much cooled by the engine oil as anything else) it's very very common to have mayonnaise-like gunk under the oil filler cap if the car is used for short journeys and never brought up to full running temperature...
     

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