Synth oil... leaks or not (ONLY real experience vote)

Discussion in 'Technical Q&A' started by enjoythemusic, May 19, 2005.


Does synth oil leak?

  1. No leaks, just the usual 'Ferrari drops.'

  2. Used synth in my car, it leaked badly

  3. My friend's sister's boyfriend heard from a guy who knows this kid who said synth oil leaks.

Multiple votes are allowed.
Results are only viewable after voting.
  1. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
    Full Name:
    AM getting tired of hearing how synth oils leak. Provided your car's gaskets are in proper shape, i feel synth will not leak. Your vote/opinions?
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  3. BAD360

    BAD360 Formula Junior

    Sep 5, 2004
    Albany/Colonie NY
    Full Name:
    It has been my experience that this is a problem with older cars and older seals. Synthetic does not impregnate the seals as well as conventional and so they shrink causing a leak. With newer cars ( post 1980) I have never experienced increased leaking due to sythetics and that goes for tranny and diff fluid as well.
  4. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    Full Name:
    marrone 308 leaked with synth in it. 20w50 castrol and it stopped. i use regular castrol 20w50 in the 77 gtb and its both clean and dry.
  5. wcelliot

    wcelliot Formula Junior

    May 7, 2004
    Maryland, USA
    Full Name:
    I have changed many old cars with no leaks from Dino to synth with no leaks.

    I have changed a few old cars that had some minor leaks and experienced the same level of leaks.

    I have changed a couple of old cars with minor leaks and experienced MAJOR leaks. (Curiously, these have all been British).

    My '78 308 belongs to group 1.

  6. Dom

    Dom F1 Veteran
    Rossa Subscribed Owner

    Nov 5, 2002
    Southern California
    Full Name:
    Dom V.
    1975 308 GT4. Have used both dino oil and synthetic (Mobil 1 15w-15). No leaks (except when my drain plug was cracked).

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  8. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    Full Name:
    Hugh G. Rection
    Used synthetics in both my 308 and leaks...other than the leaky shifter shaft seal on the 308, which dripped regardless of oil type or brand.
  9. Ken

    Ken F1 World Champ

    Oct 19, 2001
    Arlington Heights IL
    Full Name:

    I use dino oil in my Lotus and I have a small oil leak at the front cover. I am not brave enough to go to synthetic at this point, but I may next time the engine is apart and this leak is fixed.

    My 'opinion' is that a properly assembled engine will not leak. Even a Ferrari won't leak if the seals are correctly done, etc. No, I cannot prove this but I *think* many mechanics don't know the correct techniques to avoid some of the common problem areas. I doubt any Ferrari was designed with leaks from the factory.

    Older cars may be more problematic with leaks and perhaps they cannot be solved without major component replacement. So we live with the leaks.

    Just my opinions and I'm not throwing stones at mechanics.

  10. carguy

    carguy F1 Rookie

    Oct 30, 2002
    Alabama (was Mich.)
    Full Name:
    When I bought my 87 TR a few years ago it had conventional oil in it. At that time there was a small leak at the front of the motor, but nothing to get upset about. When I switched to synthetic oil after about a week the leak increased until it was horrendous. I pulled the motor and replaced the seals and all was good for a few days. Then the minor leak returned that gradually increased enough for me to worry again. I lived with it, periodically checking the cambelts for any traces of oil. As long as they are dry I'll address the leak at the next service. But I recently changed the oil back to conventional stuff and guess what....the leak is slowly decreasing. It's about 1/4 as bad as it was. I don't have any I hear both sides of the story and don't know which to believe. This is simply my real world experience.
  11. Prova85

    Prova85 Formula 3

    Nov 13, 2003
    So. Shore MA.
    Full Name:
    Kenny K
    No leaks/drips from the Tr with synth. :)

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  13. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    North shore, MA
    Full Name:
    THE Birdman
    My '77 308 had no leaks with 10W-40 dino and currently has no leaks with 5W-50 Synth.

  14. jknight

    jknight F1 Veteran

    Oct 30, 2004
    Central Texas
    1989 Mondial t coupe. Changed to Mobil 1. No leaks before the change and none after. Not even "Ferrari drops".
  15. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
    Full Name:
    So far it seems if the seals are in good condition (or at least redone by a competent mechanic), synth does not leak... unless you bought an old British car (but odds are you have Lucas electronic problems worse than oil leaks!).

    Please keep voting and commenting :)
  16. jungathart

    jungathart Guest

    Jun 11, 2004
    NoVA, AmeriKa
    Full Name:
    Komrade Jung
    No leaks of ANY fluids [including Mobil 1 synthetic] on my MD.
    The only drip she has is her idiot driver...
  17. LSU348

    LSU348 Formula 3

    Dec 19, 2003
    Sugar Land
    Full Name:
    I agree completely. My 308 does leak a little and was full of dinosaur oil when I bought it. It leaks LESS with synthetic. I mostly think that has to due to the fact that my seals are probably happier now that I drive the car more then the previous owner.

  18. vlamgat

    vlamgat Formula Junior

    Jan 9, 2004
    Have m 1 0-40 in 8 cars with no leaks on any:
    512 tr; 456M; Audi sq; Audi A4 Speed, Audi A6 4.2, Cad SRX, Ford E250, Audi Urq. Not a drop !
  19. wcelliot

    wcelliot Formula Junior

    May 7, 2004
    Maryland, USA
    Full Name:
    Actually the British cars that experienced the leaks all were "as assembled" by the factory and the engines were not that old (15 years or so) and had low mileage. I'm thinking it was more likely a function of the materials used for the seals.

    My Lucas issues have been pretty mild... with the exception of my Europa S2...and even then the problems were more Ducellier than Lucas... even my ratty XJS had fewer electrical issues than my nice SAAB 900.

    If synthetics caused significant oil leaks in most cars, then I'm sure my Corvairs (never know to retain oil well) would be at the top of the list. But I've never had a new leak start or an old leak get worse... ditto for my 83 or 85 ur-quattros, another car not known for oil retention..

  20. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    The Brickyard
    Full Name:
    The Bad Guy
    I voted no leaks. I have been using Mobile1 5w-30. The problem with Ferraris is that they aren't sealed properly. I used a CONSERVATIVE amount of Triple Bond Silicone sealer, and NO leaks. The only leaks I have now are coming from the gear box, but that is about to be torn down, so I'll take care of those leaks too. But as for oil leak, ZILCH!
  21. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Rossa Subscribed Owner

    May 4, 2001
    Birmingham, AL
    Full Name:
    Redline won't stay in mine. I use non-syn oils unless I am on the track. I have not had a drop on my driveway until I put in Redline for a track event in early March. I normally swap back after the event but I did not this time. The spots started again. First I've seen since last season.
  22. MARQ

    MARQ Formula 3

    Feb 9, 2002
    East Coast US
    Full Name:
    '88 328, changed from dino to Mobil 1 two years ago at the advice of the local Ferrari dealer. Was very skeptical due to my experience with British cars (TVRs), but to my pleasant surprise...NO LEAKS nor DROPS!!
  23. dm_n_stuff

    dm_n_stuff Global Moderator
    Global Moderator Lifetime Rossa Owner

    Dec 10, 2003
    Babcock Ranch, FL
    Full Name:
    I have redline in the gearbox.

    Once I fitted the studs with washers that have little rubber donuts in them, no leaky.

    At least not any more than before.

    And, seems to shift a little smoother.

    So, all in all, it woiks for me in the 1972 Dino.

  24. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    Full Name:
    I cant speak for the 308 yet, as its not yet running and I dont know what it had in it when I got it. I do know some people are still trying to run 25K on synthetic, and that could be part of the problem. Also, depending on the seals and gaskets and O-rings that were used in the assembly of the engine, that could be a factor as well. In the short time I have had my car I have seen both factory seals as well as aftermarket. This goes for any other car on the planet as well.

    I have never been a fan of synthetic, and I have to admit that the Mercedes Benz Club steered me away from it quite a ways, as well as a gentleman I knew who had engine failures on engines he ran Mobil 1 in. My only direct experience with synthetic is with my Ford F-350 with a 7.3 Diesel. I bought this truck used with 184K miles from Texas. It had a change sticker for M1, and some reciepts for M1 oil changes as well as some M1 oil jugs in the rear storage box.

    The motor was dripping oil all over my driveway, from the oil cooler, front cover, front seal, rear seal, and the rocker covers. If you have ever handled diesel drain oil you know the mess it makes on cement. I changed it with Dino oil and was amazed at how fast it slowed down leaking. Within a few days it was barely dripping at all, and all I had to do was tighten a few rocker cover bolts. It has not dripped a drop of oil since.

    Regarding the Mercedes Benz Club, at a tech event out in Colorado, one engineer was quoted to say that with the cars being capable of over 700,000 miles without engine work, they couldnt recommend the added cost of synthetic except in turbo cars in summer, and in the winter for diesels to aid starting.
  25. mattboyd

    mattboyd Karting

    Dec 14, 2003
    Fredericksburg, VA
    Full Name:
    Matt Boyd
    Bought my 1988 Rolls-Royce Silver Spur with 103k miles on it. It was running conventional fluid. Only after my first oil change to synthetic (Mobil 1 15w-50) did it start smoking on startup.

    Changed valve seals and seriously reduced smoking.


  26. philvecc

    philvecc Formula Junior

    Nov 3, 2003
    Longmeadow, MA
    Full Name:
    Philip Vecchiarelli
    I've had my '89 TR for almost 8 years and my '85 308 for 7 years. Both were changed over to Castrol Syn soon after I got them and there have been no leaks on either. Originally intended to use AGIP but it was easier finding Castrol. Both are driven regularly and have had oil changes yearly, and both have had majors. No complaints here!!!!
  27. 355F1UK

    355F1UK Rookie

    Feb 11, 2005
    Royal Leamington Spa
    Full Name:

    Glad to hear us brits are still unique :)
  28. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    The leaks some of you seem to have are likely caused by something other than the synthetic oil itself; such as bad seals/gaskets or loose engine assembly. A synthetic oil may be able to escape easier from bad seals gaskets or loose engine parts which would explain why you first noticed it when you used synthetic oil. But, that would still be caused by the bad seals/gaskets or loose assembly, not by the synthetic oil itself. ALL Ferraris came with either a synthetic/dino blend of full synthetic oil since the 308 I believe. FYI, Agip Sint 2000 is a synthetic blend. To just use dino oil when you notice a leak with synthetic oil would be like to stop excercising when you notice chest pain while excercising rather than having the chest pain checked out by a doctor.

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