Compression Test VS Leakdown Test, Why Bother With Both???

Discussion in 'VW Mk3 Jetta, Passat TDI and other/older diesels' started by ftm1776, Oct 23, 2016.

  1. ftm1776

    ftm1776 New Member

    Joined:
    May 26, 2014
    Messages:
    21
    Car:
    1991 VW MK2 Jetta 1.6 Diesel, Engine code ME, Non-turbo, 5 speed AWY transmission, No AC
    Location:
    Vancouver,WA
    Mods:
    Coming up on rebuild time....
    Why bother with a compression test, unless you don't have a leak down tester???

    If there is say, 10% leakage, wouldn't the compression be right up there???

    Is it possible to have low leakage and still have bad compression numbers???

    Doesn't the leak down test tell it all??? Low leakage and, if not, where the leak is originating???
     
  2. xeno555

    xeno555 Well-Known Member

    Joined:
    Dec 12, 2011
    Messages:
    1,684
    Car:
    2012 TDI Tech Package 6mt
    Location:
    Mile High
    Mods:
    Malone Stage II. Rawtek 3" from Turbo to Tail. Slammed on Koni. TSW Nurmburg Rims. Whiteline Sway & Ends. Panzer Plate.
    Compression Check:

    Check if combustion can take place.
    AKA:
    Do the valves seal?
    Rings worn?

    Leak Down (Can it hold it?):
    AKA:
    Are we going to have problems with the above?
    Did my cooling system blow apart(head leak)?
    Is air escaping through head gasket?
    Did my PCV valve blow apart(compression in to crank case)?
     

Share This Page