Jump to content

White deposit on oil filler cap

Recommended Posts



I've been looking to purchase an XK8 and viewed one recently.


I unscrewed the Oil filler cap and found a pale white greasy substance on the underside.


The Oil on the dipstick is clean and clear and smells fine.


Suspecting it may signify a head gasket problem, I mentioned this to the seller, a Jag main dealer who said he would ask their head technician.


Took the car for a test drive, had a look again at the filler cap underside and it was completely clear.


Oil pressure was constant and good as was the temperature.


The mechanic arrived, had a look and said he suspected it was simply condensation as the car has barely been used other than ferrying it a short distance to and from the workshop for various jobs.


The car seems well looked after and comes with a two year guarantee on a forty five thousand mile car.


What do members think? Do you think this could be a head gasket problem on the make and would you go ahead with the purchase? Or could it be simply condensation or something else?


Your opinion would be appreciated.



Link to comment
Share on other sites

Hi David,


"Mayonnaise" on the Oil filler cap is something us older drivers have seen before.  I have had it before on a Viva HC which my wife used for short trips.


It is probably condensation build up, but if here is no Oil in the coolant I would not think it too dangerous.  It was in the VIVA for 8 years without a problem.





Link to comment
Share on other sites

Thank you, Jim for your words.


I too am thinking the mechanic probably had it right and as you say, if the dealer is prepared to stand a two years guarantee behind the car, it's probably not something to worry about.


Thank you Jim, I appreciate your taking time to respond.





Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Join The Club

    Join the Jaguar Owners Club and be part of the Community. It's FREE!

  • Topics

  • Our picks

    • Simply Jaguar - Beaulieu Motor Museum - 25th June 2023
      Jaguar Owners Club have a stand at this years Simply Jaguar event at the National Motor Museum at Beaulieu, Hampshire on Sunday 26th June 2023

      Tickets are available online here: https://www.beaulieu.co.uk/events/simply-jaguar/

      Participant prices are only valid if arriving in a Jaguar and taking part in the rally. They are not valid for those arriving on foot.

      Participants can make the most of our EARLY BIRD discount by booking before 28th February 2023.

      Children under 5 require a ticket, this can be booked online free of charge.

      Participant and visitor tickets will include entrance to the rest of the Beaulieu attraction, including the National Motor Museum, Palace House, Little Beaulieu, World of Top Gear, Beaulieu Abbey and its grounds and gardens.

      The best time for viewing the Simply rally is between 10am and 2pm.





      Participants – Early Bird*



      Participants – Standard & On The Day




      Normal admission applies.

      Normal admission applies

      *Early bird tickets are available until 28th February 2023

      Entry with your Jaguar is from 9am – 2pm. Please make sure you have your ticket printed or available on your phone, ready to be scanned on arrival.

      Please do not arrive early for our Simply rallies as no facilities will be open prior to 9:30am.

      Cars cannot leave and re-enter the grounds for the Simply rallies.



      We do ask for a final update on numbers 2 weeks prior to the event following which we will send out club labels to you via email for you to then distribute out to club members. Club members then need to print and display these in their windscreen on arrival. This helps us then park you all in your club area together.

      1. Trevor (admin)
      2.  Paj
      • 3 replies
    • F-TYPE marks 75 years of Jaguar sports cars and its final model year update
      The Jaguar F-TYPE is the definitive Jaguar sports car from a rich bloodline spanning 75 years and including some of the most iconic models ever built
    • Jaguar partners with Andersen EV for luxury, customisable home charging
      Owners of electrified Jaguar and Land Rover models will be able to charge their vehicles at home with unrivalled style thanks to a new agreement with fellow British company Andersen EV

      Owners of electrified Jaguar and Land Rover models will be able to charge their vehicles at home with unrivalled style thanks to a new agreement with fellow British company Andersen EV.
    • First production Jaguar C-Type Continuation ready for customer delivery on landmark anniversary
      Jaguar Classic has completed building the first C-type Continuation. The strictly limited production run is well underway at Jaguar’s Classic Works, Coventry, and the first vehicle has finished shakedown testing ready for delivery to an excited customer
    • Simply Jaguar - Beaulieu Motor Museum - 26th June 2022
      Jaguar Owners Club have a stand at this years Simply Jaguar event at the National Motor Museum at Beaulieu, Hampshire on Sunday 26th June 2022.
      • 11 replies

  • Create New...